1477 lines
53 KiB
Java
1477 lines
53 KiB
Java
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/*
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* Copyright (C) 2006 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.widget;
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import com.android.internal.R;
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import android.content.Context;
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import android.content.res.Resources;
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import android.content.res.TypedArray;
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import android.graphics.Canvas;
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import android.graphics.Rect;
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import android.graphics.drawable.Drawable;
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import android.util.AttributeSet;
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import android.view.FocusFinder;
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import android.view.KeyEvent;
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import android.view.MotionEvent;
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import android.view.VelocityTracker;
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import android.view.View;
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import android.view.ViewConfiguration;
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import android.view.ViewGroup;
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import android.view.ViewParent;
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import android.view.animation.AnimationUtils;
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import java.util.List;
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/**
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* Layout container for a view hierarchy that can be scrolled by the user,
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* allowing it to be larger than the physical display. A ScrollView
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* is a {@link FrameLayout}, meaning you should place one child in it
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* containing the entire contents to scroll; this child may itself be a layout
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* manager with a complex hierarchy of objects. A child that is often used
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* is a {@link LinearLayout} in a vertical orientation, presenting a vertical
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* array of top-level items that the user can scroll through.
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*
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* <p>The {@link TextView} class also
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* takes care of its own scrolling, so does not require a ScrollView, but
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* using the two together is possible to achieve the effect of a text view
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* within a larger container.
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*
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* <p>ScrollView only supports vertical scrolling.
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*/
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public class ScrollView extends FrameLayout {
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static final int ANIMATED_SCROLL_GAP = 250;
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static final float MAX_SCROLL_FACTOR = 0.5f;
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private long mLastScroll;
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private final Rect mTempRect = new Rect();
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private OverScroller mScroller;
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private EdgeGlow mEdgeGlowTop;
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private EdgeGlow mEdgeGlowBottom;
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/**
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* Flag to indicate that we are moving focus ourselves. This is so the
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* code that watches for focus changes initiated outside this ScrollView
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* knows that it does not have to do anything.
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*/
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private boolean mScrollViewMovedFocus;
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/**
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* Position of the last motion event.
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*/
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private float mLastMotionY;
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/**
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* True when the layout has changed but the traversal has not come through yet.
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* Ideally the view hierarchy would keep track of this for us.
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*/
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private boolean mIsLayoutDirty = true;
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/**
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* The child to give focus to in the event that a child has requested focus while the
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* layout is dirty. This prevents the scroll from being wrong if the child has not been
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* laid out before requesting focus.
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*/
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private View mChildToScrollTo = null;
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/**
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* True if the user is currently dragging this ScrollView around. This is
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* not the same as 'is being flinged', which can be checked by
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* mScroller.isFinished() (flinging begins when the user lifts his finger).
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*/
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private boolean mIsBeingDragged = false;
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/**
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* Determines speed during touch scrolling
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*/
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private VelocityTracker mVelocityTracker;
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/**
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* When set to true, the scroll view measure its child to make it fill the currently
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* visible area.
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*/
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private boolean mFillViewport;
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/**
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* Whether arrow scrolling is animated.
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*/
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private boolean mSmoothScrollingEnabled = true;
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private int mTouchSlop;
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private int mMinimumVelocity;
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private int mMaximumVelocity;
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private int mOverscrollDistance;
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private int mOverflingDistance;
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/**
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* ID of the active pointer. This is used to retain consistency during
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* drags/flings if multiple pointers are used.
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*/
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private int mActivePointerId = INVALID_POINTER;
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/**
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* Sentinel value for no current active pointer.
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* Used by {@link #mActivePointerId}.
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*/
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private static final int INVALID_POINTER = -1;
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public ScrollView(Context context) {
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this(context, null);
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}
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public ScrollView(Context context, AttributeSet attrs) {
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this(context, attrs, com.android.internal.R.attr.scrollViewStyle);
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}
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public ScrollView(Context context, AttributeSet attrs, int defStyle) {
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super(context, attrs, defStyle);
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initScrollView();
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TypedArray a =
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context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.ScrollView, defStyle, 0);
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setFillViewport(a.getBoolean(R.styleable.ScrollView_fillViewport, false));
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a.recycle();
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}
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@Override
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protected float getTopFadingEdgeStrength() {
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if (getChildCount() == 0) {
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return 0.0f;
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}
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final int length = getVerticalFadingEdgeLength();
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if (mScrollY < length) {
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return mScrollY / (float) length;
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}
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return 1.0f;
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}
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@Override
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protected float getBottomFadingEdgeStrength() {
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if (getChildCount() == 0) {
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return 0.0f;
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}
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final int length = getVerticalFadingEdgeLength();
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final int bottomEdge = getHeight() - mPaddingBottom;
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final int span = getChildAt(0).getBottom() - mScrollY - bottomEdge;
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if (span < length) {
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return span / (float) length;
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}
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return 1.0f;
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}
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/**
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* @return The maximum amount this scroll view will scroll in response to
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* an arrow event.
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*/
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public int getMaxScrollAmount() {
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return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop));
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}
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private void initScrollView() {
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mScroller = new OverScroller(getContext());
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setFocusable(true);
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setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
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setWillNotDraw(false);
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final ViewConfiguration configuration = ViewConfiguration.get(mContext);
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mTouchSlop = configuration.getScaledTouchSlop();
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mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
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mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
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mOverscrollDistance = configuration.getScaledOverscrollDistance();
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mOverflingDistance = configuration.getScaledOverflingDistance();
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}
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@Override
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public void addView(View child) {
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if (getChildCount() > 0) {
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throw new IllegalStateException("ScrollView can host only one direct child");
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}
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super.addView(child);
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}
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@Override
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public void addView(View child, int index) {
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if (getChildCount() > 0) {
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throw new IllegalStateException("ScrollView can host only one direct child");
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}
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super.addView(child, index);
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}
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@Override
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public void addView(View child, ViewGroup.LayoutParams params) {
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if (getChildCount() > 0) {
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throw new IllegalStateException("ScrollView can host only one direct child");
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}
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super.addView(child, params);
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}
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@Override
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public void addView(View child, int index, ViewGroup.LayoutParams params) {
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if (getChildCount() > 0) {
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throw new IllegalStateException("ScrollView can host only one direct child");
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}
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super.addView(child, index, params);
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}
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/**
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* @return Returns true this ScrollView can be scrolled
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*/
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private boolean canScroll() {
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View child = getChildAt(0);
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if (child != null) {
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int childHeight = child.getHeight();
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return getHeight() < childHeight + mPaddingTop + mPaddingBottom;
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}
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return false;
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}
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/**
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* Indicates whether this ScrollView's content is stretched to fill the viewport.
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*
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* @return True if the content fills the viewport, false otherwise.
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*/
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public boolean isFillViewport() {
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return mFillViewport;
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}
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/**
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* Indicates this ScrollView whether it should stretch its content height to fill
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* the viewport or not.
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*
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* @param fillViewport True to stretch the content's height to the viewport's
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* boundaries, false otherwise.
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*/
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public void setFillViewport(boolean fillViewport) {
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if (fillViewport != mFillViewport) {
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mFillViewport = fillViewport;
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requestLayout();
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}
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}
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/**
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* @return Whether arrow scrolling will animate its transition.
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*/
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public boolean isSmoothScrollingEnabled() {
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return mSmoothScrollingEnabled;
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}
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/**
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* Set whether arrow scrolling will animate its transition.
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* @param smoothScrollingEnabled whether arrow scrolling will animate its transition
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*/
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public void setSmoothScrollingEnabled(boolean smoothScrollingEnabled) {
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mSmoothScrollingEnabled = smoothScrollingEnabled;
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}
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@Override
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protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
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super.onMeasure(widthMeasureSpec, heightMeasureSpec);
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if (!mFillViewport) {
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return;
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}
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final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
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if (heightMode == MeasureSpec.UNSPECIFIED) {
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return;
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}
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if (getChildCount() > 0) {
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final View child = getChildAt(0);
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int height = getMeasuredHeight();
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if (child.getMeasuredHeight() < height) {
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final FrameLayout.LayoutParams lp = (LayoutParams) child.getLayoutParams();
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int childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec, mPaddingLeft
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+ mPaddingRight, lp.width);
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height -= mPaddingTop;
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height -= mPaddingBottom;
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int childHeightMeasureSpec =
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MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
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child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
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}
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}
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}
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@Override
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public boolean dispatchKeyEvent(KeyEvent event) {
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// Let the focused view and/or our descendants get the key first
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return super.dispatchKeyEvent(event) || executeKeyEvent(event);
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}
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/**
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* You can call this function yourself to have the scroll view perform
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* scrolling from a key event, just as if the event had been dispatched to
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* it by the view hierarchy.
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*
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* @param event The key event to execute.
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* @return Return true if the event was handled, else false.
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*/
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public boolean executeKeyEvent(KeyEvent event) {
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mTempRect.setEmpty();
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if (!canScroll()) {
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if (isFocused() && event.getKeyCode() != KeyEvent.KEYCODE_BACK) {
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View currentFocused = findFocus();
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if (currentFocused == this) currentFocused = null;
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View nextFocused = FocusFinder.getInstance().findNextFocus(this,
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currentFocused, View.FOCUS_DOWN);
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return nextFocused != null
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&& nextFocused != this
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&& nextFocused.requestFocus(View.FOCUS_DOWN);
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}
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return false;
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}
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boolean handled = false;
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if (event.getAction() == KeyEvent.ACTION_DOWN) {
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switch (event.getKeyCode()) {
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case KeyEvent.KEYCODE_DPAD_UP:
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if (!event.isAltPressed()) {
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handled = arrowScroll(View.FOCUS_UP);
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} else {
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handled = fullScroll(View.FOCUS_UP);
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}
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break;
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case KeyEvent.KEYCODE_DPAD_DOWN:
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if (!event.isAltPressed()) {
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handled = arrowScroll(View.FOCUS_DOWN);
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} else {
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handled = fullScroll(View.FOCUS_DOWN);
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}
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break;
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case KeyEvent.KEYCODE_SPACE:
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pageScroll(event.isShiftPressed() ? View.FOCUS_UP : View.FOCUS_DOWN);
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break;
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}
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}
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return handled;
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}
|
||
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private boolean inChild(int x, int y) {
|
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if (getChildCount() > 0) {
|
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final int scrollY = mScrollY;
|
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final View child = getChildAt(0);
|
||
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return !(y < child.getTop() - scrollY
|
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|| y >= child.getBottom() - scrollY
|
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|| x < child.getLeft()
|
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|| x >= child.getRight());
|
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}
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return false;
|
||
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}
|
||
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||
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@Override
|
||
|
|
public boolean onInterceptTouchEvent(MotionEvent ev) {
|
||
|
|
/*
|
||
|
|
* This method JUST determines whether we want to intercept the motion.
|
||
|
|
* If we return true, onMotionEvent will be called and we do the actual
|
||
|
|
* scrolling there.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Shortcut the most recurring case: the user is in the dragging
|
||
|
|
* state and he is moving his finger. We want to intercept this
|
||
|
|
* motion.
|
||
|
|
*/
|
||
|
|
final int action = ev.getAction();
|
||
|
|
if ((action == MotionEvent.ACTION_MOVE) && (mIsBeingDragged)) {
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
switch (action & MotionEvent.ACTION_MASK) {
|
||
|
|
case MotionEvent.ACTION_MOVE: {
|
||
|
|
/*
|
||
|
|
* mIsBeingDragged == false, otherwise the shortcut would have caught it. Check
|
||
|
|
* whether the user has moved far enough from his original down touch.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Locally do absolute value. mLastMotionY is set to the y value
|
||
|
|
* of the down event.
|
||
|
|
*/
|
||
|
|
final int activePointerId = mActivePointerId;
|
||
|
|
if (activePointerId == INVALID_POINTER) {
|
||
|
|
// If we don't have a valid id, the touch down wasn't on content.
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
final int pointerIndex = ev.findPointerIndex(activePointerId);
|
||
|
|
if (pointerIndex == -1) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
final float y = ev.getY(pointerIndex);
|
||
|
|
final int yDiff = (int) Math.abs(y - mLastMotionY);
|
||
|
|
if (yDiff > mTouchSlop) {
|
||
|
|
mIsBeingDragged = true;
|
||
|
|
mLastMotionY = y;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
case MotionEvent.ACTION_DOWN: {
|
||
|
|
final float y = ev.getY();
|
||
|
|
if (!inChild((int) ev.getX(), (int) y)) {
|
||
|
|
mIsBeingDragged = false;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Remember location of down touch.
|
||
|
|
* ACTION_DOWN always refers to pointer index 0.
|
||
|
|
*/
|
||
|
|
mLastMotionY = y;
|
||
|
|
mActivePointerId = ev.getPointerId(0);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If being flinged and user touches the screen, initiate drag;
|
||
|
|
* otherwise don't. mScroller.isFinished should be false when
|
||
|
|
* being flinged.
|
||
|
|
*/
|
||
|
|
mIsBeingDragged = !mScroller.isFinished();
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
case MotionEvent.ACTION_CANCEL:
|
||
|
|
case MotionEvent.ACTION_UP:
|
||
|
|
/* Release the drag */
|
||
|
|
mIsBeingDragged = false;
|
||
|
|
mActivePointerId = INVALID_POINTER;
|
||
|
|
if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange())) {
|
||
|
|
invalidate();
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case MotionEvent.ACTION_POINTER_UP:
|
||
|
|
onSecondaryPointerUp(ev);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The only time we want to intercept motion events is if we are in the
|
||
|
|
* drag mode.
|
||
|
|
*/
|
||
|
|
return mIsBeingDragged;
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public boolean onTouchEvent(MotionEvent ev) {
|
||
|
|
|
||
|
|
if (ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) {
|
||
|
|
// Don't handle edge touches immediately -- they may actually belong to one of our
|
||
|
|
// descendants.
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (mVelocityTracker == null) {
|
||
|
|
mVelocityTracker = VelocityTracker.obtain();
|
||
|
|
}
|
||
|
|
mVelocityTracker.addMovement(ev);
|
||
|
|
|
||
|
|
final int action = ev.getAction();
|
||
|
|
|
||
|
|
switch (action & MotionEvent.ACTION_MASK) {
|
||
|
|
case MotionEvent.ACTION_DOWN: {
|
||
|
|
mIsBeingDragged = getChildCount() != 0;
|
||
|
|
if (!mIsBeingDragged) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If being flinged and user touches, stop the fling. isFinished
|
||
|
|
* will be false if being flinged.
|
||
|
|
*/
|
||
|
|
if (!mScroller.isFinished()) {
|
||
|
|
mScroller.abortAnimation();
|
||
|
|
}
|
||
|
|
|
||
|
|
// Remember where the motion event started
|
||
|
|
mLastMotionY = ev.getY();
|
||
|
|
mActivePointerId = ev.getPointerId(0);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
case MotionEvent.ACTION_MOVE:
|
||
|
|
if (mIsBeingDragged) {
|
||
|
|
// Scroll to follow the motion event
|
||
|
|
final int activePointerIndex = ev.findPointerIndex(mActivePointerId);
|
||
|
|
if (activePointerIndex == -1) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
final float y = ev.getY(activePointerIndex);
|
||
|
|
final int deltaY = (int) (mLastMotionY - y);
|
||
|
|
mLastMotionY = y;
|
||
|
|
|
||
|
|
final int oldX = mScrollX;
|
||
|
|
final int oldY = mScrollY;
|
||
|
|
final int range = getScrollRange();
|
||
|
|
if (overScrollBy(0, deltaY, 0, mScrollY, 0, range,
|
||
|
|
0, mOverscrollDistance, true)) {
|
||
|
|
// Break our velocity if we hit a scroll barrier.
|
||
|
|
mVelocityTracker.clear();
|
||
|
|
}
|
||
|
|
onScrollChanged(mScrollX, mScrollY, oldX, oldY);
|
||
|
|
|
||
|
|
final int overscrollMode = getOverScrollMode();
|
||
|
|
if (overscrollMode == OVER_SCROLL_ALWAYS ||
|
||
|
|
(overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0)) {
|
||
|
|
final int pulledToY = oldY + deltaY;
|
||
|
|
if (pulledToY < 0) {
|
||
|
|
mEdgeGlowTop.onPull((float) deltaY / getHeight());
|
||
|
|
if (!mEdgeGlowBottom.isFinished()) {
|
||
|
|
mEdgeGlowBottom.onRelease();
|
||
|
|
}
|
||
|
|
} else if (pulledToY > range) {
|
||
|
|
mEdgeGlowBottom.onPull((float) deltaY / getHeight());
|
||
|
|
if (!mEdgeGlowTop.isFinished()) {
|
||
|
|
mEdgeGlowTop.onRelease();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (mEdgeGlowTop != null
|
||
|
|
&& (!mEdgeGlowTop.isFinished() || !mEdgeGlowBottom.isFinished())) {
|
||
|
|
invalidate();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case MotionEvent.ACTION_UP:
|
||
|
|
if (mIsBeingDragged) {
|
||
|
|
final VelocityTracker velocityTracker = mVelocityTracker;
|
||
|
|
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
|
||
|
|
int initialVelocity = (int) velocityTracker.getYVelocity(mActivePointerId);
|
||
|
|
|
||
|
|
if (getChildCount() > 0) {
|
||
|
|
if ((Math.abs(initialVelocity) > mMinimumVelocity)) {
|
||
|
|
fling(-initialVelocity);
|
||
|
|
} else {
|
||
|
|
final int bottom = getScrollRange();
|
||
|
|
if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, bottom)) {
|
||
|
|
invalidate();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
mActivePointerId = INVALID_POINTER;
|
||
|
|
mIsBeingDragged = false;
|
||
|
|
|
||
|
|
if (mVelocityTracker != null) {
|
||
|
|
mVelocityTracker.recycle();
|
||
|
|
mVelocityTracker = null;
|
||
|
|
}
|
||
|
|
if (mEdgeGlowTop != null) {
|
||
|
|
mEdgeGlowTop.onRelease();
|
||
|
|
mEdgeGlowBottom.onRelease();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case MotionEvent.ACTION_CANCEL:
|
||
|
|
if (mIsBeingDragged && getChildCount() > 0) {
|
||
|
|
if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange())) {
|
||
|
|
invalidate();
|
||
|
|
}
|
||
|
|
mActivePointerId = INVALID_POINTER;
|
||
|
|
mIsBeingDragged = false;
|
||
|
|
if (mVelocityTracker != null) {
|
||
|
|
mVelocityTracker.recycle();
|
||
|
|
mVelocityTracker = null;
|
||
|
|
}
|
||
|
|
if (mEdgeGlowTop != null) {
|
||
|
|
mEdgeGlowTop.onRelease();
|
||
|
|
mEdgeGlowBottom.onRelease();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
case MotionEvent.ACTION_POINTER_UP:
|
||
|
|
onSecondaryPointerUp(ev);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
private void onSecondaryPointerUp(MotionEvent ev) {
|
||
|
|
final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >>
|
||
|
|
MotionEvent.ACTION_POINTER_INDEX_SHIFT;
|
||
|
|
final int pointerId = ev.getPointerId(pointerIndex);
|
||
|
|
if (pointerId == mActivePointerId) {
|
||
|
|
// This was our active pointer going up. Choose a new
|
||
|
|
// active pointer and adjust accordingly.
|
||
|
|
// TODO: Make this decision more intelligent.
|
||
|
|
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
|
||
|
|
mLastMotionY = ev.getY(newPointerIndex);
|
||
|
|
mActivePointerId = ev.getPointerId(newPointerIndex);
|
||
|
|
if (mVelocityTracker != null) {
|
||
|
|
mVelocityTracker.clear();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
protected void onOverScrolled(int scrollX, int scrollY,
|
||
|
|
boolean clampedX, boolean clampedY) {
|
||
|
|
// Treat animating scrolls differently; see #computeScroll() for why.
|
||
|
|
if (!mScroller.isFinished()) {
|
||
|
|
mScrollX = scrollX;
|
||
|
|
mScrollY = scrollY;
|
||
|
|
if (clampedY) {
|
||
|
|
mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange());
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
super.scrollTo(scrollX, scrollY);
|
||
|
|
}
|
||
|
|
awakenScrollBars();
|
||
|
|
}
|
||
|
|
|
||
|
|
private int getScrollRange() {
|
||
|
|
int scrollRange = 0;
|
||
|
|
if (getChildCount() > 0) {
|
||
|
|
View child = getChildAt(0);
|
||
|
|
scrollRange = Math.max(0,
|
||
|
|
child.getHeight() - (getHeight() - mPaddingBottom - mPaddingTop));
|
||
|
|
}
|
||
|
|
return scrollRange;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* <p>
|
||
|
|
* Finds the next focusable component that fits in this View's bounds
|
||
|
|
* (excluding fading edges) pretending that this View's top is located at
|
||
|
|
* the parameter top.
|
||
|
|
* </p>
|
||
|
|
*
|
||
|
|
* @param topFocus look for a candidate is the one at the top of the bounds
|
||
|
|
* if topFocus is true, or at the bottom of the bounds if topFocus is
|
||
|
|
* false
|
||
|
|
* @param top the top offset of the bounds in which a focusable must be
|
||
|
|
* found (the fading edge is assumed to start at this position)
|
||
|
|
* @param preferredFocusable the View that has highest priority and will be
|
||
|
|
* returned if it is within my bounds (null is valid)
|
||
|
|
* @return the next focusable component in the bounds or null if none can be
|
||
|
|
* found
|
||
|
|
*/
|
||
|
|
private View findFocusableViewInMyBounds(final boolean topFocus,
|
||
|
|
final int top, View preferredFocusable) {
|
||
|
|
/*
|
||
|
|
* The fading edge's transparent side should be considered for focus
|
||
|
|
* since it's mostly visible, so we divide the actual fading edge length
|
||
|
|
* by 2.
|
||
|
|
*/
|
||
|
|
final int fadingEdgeLength = getVerticalFadingEdgeLength() / 2;
|
||
|
|
final int topWithoutFadingEdge = top + fadingEdgeLength;
|
||
|
|
final int bottomWithoutFadingEdge = top + getHeight() - fadingEdgeLength;
|
||
|
|
|
||
|
|
if ((preferredFocusable != null)
|
||
|
|
&& (preferredFocusable.getTop() < bottomWithoutFadingEdge)
|
||
|
|
&& (preferredFocusable.getBottom() > topWithoutFadingEdge)) {
|
||
|
|
return preferredFocusable;
|
||
|
|
}
|
||
|
|
|
||
|
|
return findFocusableViewInBounds(topFocus, topWithoutFadingEdge,
|
||
|
|
bottomWithoutFadingEdge);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* <p>
|
||
|
|
* Finds the next focusable component that fits in the specified bounds.
|
||
|
|
* </p>
|
||
|
|
*
|
||
|
|
* @param topFocus look for a candidate is the one at the top of the bounds
|
||
|
|
* if topFocus is true, or at the bottom of the bounds if topFocus is
|
||
|
|
* false
|
||
|
|
* @param top the top offset of the bounds in which a focusable must be
|
||
|
|
* found
|
||
|
|
* @param bottom the bottom offset of the bounds in which a focusable must
|
||
|
|
* be found
|
||
|
|
* @return the next focusable component in the bounds or null if none can
|
||
|
|
* be found
|
||
|
|
*/
|
||
|
|
private View findFocusableViewInBounds(boolean topFocus, int top, int bottom) {
|
||
|
|
|
||
|
|
List<View> focusables = getFocusables(View.FOCUS_FORWARD);
|
||
|
|
View focusCandidate = null;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* A fully contained focusable is one where its top is below the bound's
|
||
|
|
* top, and its bottom is above the bound's bottom. A partially
|
||
|
|
* contained focusable is one where some part of it is within the
|
||
|
|
* bounds, but it also has some part that is not within bounds. A fully contained
|
||
|
|
* focusable is preferred to a partially contained focusable.
|
||
|
|
*/
|
||
|
|
boolean foundFullyContainedFocusable = false;
|
||
|
|
|
||
|
|
int count = focusables.size();
|
||
|
|
for (int i = 0; i < count; i++) {
|
||
|
|
View view = focusables.get(i);
|
||
|
|
int viewTop = view.getTop();
|
||
|
|
int viewBottom = view.getBottom();
|
||
|
|
|
||
|
|
if (top < viewBottom && viewTop < bottom) {
|
||
|
|
/*
|
||
|
|
* the focusable is in the target area, it is a candidate for
|
||
|
|
* focusing
|
||
|
|
*/
|
||
|
|
|
||
|
|
final boolean viewIsFullyContained = (top < viewTop) &&
|
||
|
|
(viewBottom < bottom);
|
||
|
|
|
||
|
|
if (focusCandidate == null) {
|
||
|
|
/* No candidate, take this one */
|
||
|
|
focusCandidate = view;
|
||
|
|
foundFullyContainedFocusable = viewIsFullyContained;
|
||
|
|
} else {
|
||
|
|
final boolean viewIsCloserToBoundary =
|
||
|
|
(topFocus && viewTop < focusCandidate.getTop()) ||
|
||
|
|
(!topFocus && viewBottom > focusCandidate
|
||
|
|
.getBottom());
|
||
|
|
|
||
|
|
if (foundFullyContainedFocusable) {
|
||
|
|
if (viewIsFullyContained && viewIsCloserToBoundary) {
|
||
|
|
/*
|
||
|
|
* We're dealing with only fully contained views, so
|
||
|
|
* it has to be closer to the boundary to beat our
|
||
|
|
* candidate
|
||
|
|
*/
|
||
|
|
focusCandidate = view;
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
if (viewIsFullyContained) {
|
||
|
|
/* Any fully contained view beats a partially contained view */
|
||
|
|
focusCandidate = view;
|
||
|
|
foundFullyContainedFocusable = true;
|
||
|
|
} else if (viewIsCloserToBoundary) {
|
||
|
|
/*
|
||
|
|
* Partially contained view beats another partially
|
||
|
|
* contained view if it's closer
|
||
|
|
*/
|
||
|
|
focusCandidate = view;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return focusCandidate;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* <p>Handles scrolling in response to a "page up/down" shortcut press. This
|
||
|
|
* method will scroll the view by one page up or down and give the focus
|
||
|
|
* to the topmost/bottommost component in the new visible area. If no
|
||
|
|
* component is a good candidate for focus, this scrollview reclaims the
|
||
|
|
* focus.</p>
|
||
|
|
*
|
||
|
|
* @param direction the scroll direction: {@link android.view.View#FOCUS_UP}
|
||
|
|
* to go one page up or
|
||
|
|
* {@link android.view.View#FOCUS_DOWN} to go one page down
|
||
|
|
* @return true if the key event is consumed by this method, false otherwise
|
||
|
|
*/
|
||
|
|
public boolean pageScroll(int direction) {
|
||
|
|
boolean down = direction == View.FOCUS_DOWN;
|
||
|
|
int height = getHeight();
|
||
|
|
|
||
|
|
if (down) {
|
||
|
|
mTempRect.top = getScrollY() + height;
|
||
|
|
int count = getChildCount();
|
||
|
|
if (count > 0) {
|
||
|
|
View view = getChildAt(count - 1);
|
||
|
|
if (mTempRect.top + height > view.getBottom()) {
|
||
|
|
mTempRect.top = view.getBottom() - height;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
mTempRect.top = getScrollY() - height;
|
||
|
|
if (mTempRect.top < 0) {
|
||
|
|
mTempRect.top = 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
mTempRect.bottom = mTempRect.top + height;
|
||
|
|
|
||
|
|
return scrollAndFocus(direction, mTempRect.top, mTempRect.bottom);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* <p>Handles scrolling in response to a "home/end" shortcut press. This
|
||
|
|
* method will scroll the view to the top or bottom and give the focus
|
||
|
|
* to the topmost/bottommost component in the new visible area. If no
|
||
|
|
* component is a good candidate for focus, this scrollview reclaims the
|
||
|
|
* focus.</p>
|
||
|
|
*
|
||
|
|
* @param direction the scroll direction: {@link android.view.View#FOCUS_UP}
|
||
|
|
* to go the top of the view or
|
||
|
|
* {@link android.view.View#FOCUS_DOWN} to go the bottom
|
||
|
|
* @return true if the key event is consumed by this method, false otherwise
|
||
|
|
*/
|
||
|
|
public boolean fullScroll(int direction) {
|
||
|
|
boolean down = direction == View.FOCUS_DOWN;
|
||
|
|
int height = getHeight();
|
||
|
|
|
||
|
|
mTempRect.top = 0;
|
||
|
|
mTempRect.bottom = height;
|
||
|
|
|
||
|
|
if (down) {
|
||
|
|
int count = getChildCount();
|
||
|
|
if (count > 0) {
|
||
|
|
View view = getChildAt(count - 1);
|
||
|
|
mTempRect.bottom = view.getBottom();
|
||
|
|
mTempRect.top = mTempRect.bottom - height;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return scrollAndFocus(direction, mTempRect.top, mTempRect.bottom);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* <p>Scrolls the view to make the area defined by <code>top</code> and
|
||
|
|
* <code>bottom</code> visible. This method attempts to give the focus
|
||
|
|
* to a component visible in this area. If no component can be focused in
|
||
|
|
* the new visible area, the focus is reclaimed by this scrollview.</p>
|
||
|
|
*
|
||
|
|
* @param direction the scroll direction: {@link android.view.View#FOCUS_UP}
|
||
|
|
* to go upward
|
||
|
|
* {@link android.view.View#FOCUS_DOWN} to downward
|
||
|
|
* @param top the top offset of the new area to be made visible
|
||
|
|
* @param bottom the bottom offset of the new area to be made visible
|
||
|
|
* @return true if the key event is consumed by this method, false otherwise
|
||
|
|
*/
|
||
|
|
private boolean scrollAndFocus(int direction, int top, int bottom) {
|
||
|
|
boolean handled = true;
|
||
|
|
|
||
|
|
int height = getHeight();
|
||
|
|
int containerTop = getScrollY();
|
||
|
|
int containerBottom = containerTop + height;
|
||
|
|
boolean up = direction == View.FOCUS_UP;
|
||
|
|
|
||
|
|
View newFocused = findFocusableViewInBounds(up, top, bottom);
|
||
|
|
if (newFocused == null) {
|
||
|
|
newFocused = this;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (top >= containerTop && bottom <= containerBottom) {
|
||
|
|
handled = false;
|
||
|
|
} else {
|
||
|
|
int delta = up ? (top - containerTop) : (bottom - containerBottom);
|
||
|
|
doScrollY(delta);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (newFocused != findFocus() && newFocused.requestFocus(direction)) {
|
||
|
|
mScrollViewMovedFocus = true;
|
||
|
|
mScrollViewMovedFocus = false;
|
||
|
|
}
|
||
|
|
|
||
|
|
return handled;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Handle scrolling in response to an up or down arrow click.
|
||
|
|
*
|
||
|
|
* @param direction The direction corresponding to the arrow key that was
|
||
|
|
* pressed
|
||
|
|
* @return True if we consumed the event, false otherwise
|
||
|
|
*/
|
||
|
|
public boolean arrowScroll(int direction) {
|
||
|
|
|
||
|
|
View currentFocused = findFocus();
|
||
|
|
if (currentFocused == this) currentFocused = null;
|
||
|
|
|
||
|
|
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction);
|
||
|
|
|
||
|
|
final int maxJump = getMaxScrollAmount();
|
||
|
|
|
||
|
|
if (nextFocused != null && isWithinDeltaOfScreen(nextFocused, maxJump, getHeight())) {
|
||
|
|
nextFocused.getDrawingRect(mTempRect);
|
||
|
|
offsetDescendantRectToMyCoords(nextFocused, mTempRect);
|
||
|
|
int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect);
|
||
|
|
doScrollY(scrollDelta);
|
||
|
|
nextFocused.requestFocus(direction);
|
||
|
|
} else {
|
||
|
|
// no new focus
|
||
|
|
int scrollDelta = maxJump;
|
||
|
|
|
||
|
|
if (direction == View.FOCUS_UP && getScrollY() < scrollDelta) {
|
||
|
|
scrollDelta = getScrollY();
|
||
|
|
} else if (direction == View.FOCUS_DOWN) {
|
||
|
|
if (getChildCount() > 0) {
|
||
|
|
int daBottom = getChildAt(0).getBottom();
|
||
|
|
|
||
|
|
int screenBottom = getScrollY() + getHeight();
|
||
|
|
|
||
|
|
if (daBottom - screenBottom < maxJump) {
|
||
|
|
scrollDelta = daBottom - screenBottom;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (scrollDelta == 0) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
doScrollY(direction == View.FOCUS_DOWN ? scrollDelta : -scrollDelta);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (currentFocused != null && currentFocused.isFocused()
|
||
|
|
&& isOffScreen(currentFocused)) {
|
||
|
|
// previously focused item still has focus and is off screen, give
|
||
|
|
// it up (take it back to ourselves)
|
||
|
|
// (also, need to temporarily force FOCUS_BEFORE_DESCENDANTS so we are
|
||
|
|
// sure to
|
||
|
|
// get it)
|
||
|
|
final int descendantFocusability = getDescendantFocusability(); // save
|
||
|
|
setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);
|
||
|
|
requestFocus();
|
||
|
|
setDescendantFocusability(descendantFocusability); // restore
|
||
|
|
}
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @return whether the descendant of this scroll view is scrolled off
|
||
|
|
* screen.
|
||
|
|
*/
|
||
|
|
private boolean isOffScreen(View descendant) {
|
||
|
|
return !isWithinDeltaOfScreen(descendant, 0, getHeight());
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @return whether the descendant of this scroll view is within delta
|
||
|
|
* pixels of being on the screen.
|
||
|
|
*/
|
||
|
|
private boolean isWithinDeltaOfScreen(View descendant, int delta, int height) {
|
||
|
|
descendant.getDrawingRect(mTempRect);
|
||
|
|
offsetDescendantRectToMyCoords(descendant, mTempRect);
|
||
|
|
|
||
|
|
return (mTempRect.bottom + delta) >= getScrollY()
|
||
|
|
&& (mTempRect.top - delta) <= (getScrollY() + height);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Smooth scroll by a Y delta
|
||
|
|
*
|
||
|
|
* @param delta the number of pixels to scroll by on the Y axis
|
||
|
|
*/
|
||
|
|
private void doScrollY(int delta) {
|
||
|
|
if (delta != 0) {
|
||
|
|
if (mSmoothScrollingEnabled) {
|
||
|
|
smoothScrollBy(0, delta);
|
||
|
|
} else {
|
||
|
|
scrollBy(0, delta);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Like {@link View#scrollBy}, but scroll smoothly instead of immediately.
|
||
|
|
*
|
||
|
|
* @param dx the number of pixels to scroll by on the X axis
|
||
|
|
* @param dy the number of pixels to scroll by on the Y axis
|
||
|
|
*/
|
||
|
|
public final void smoothScrollBy(int dx, int dy) {
|
||
|
|
if (getChildCount() == 0) {
|
||
|
|
// Nothing to do.
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
long duration = AnimationUtils.currentAnimationTimeMillis() - mLastScroll;
|
||
|
|
if (duration > ANIMATED_SCROLL_GAP) {
|
||
|
|
final int height = getHeight() - mPaddingBottom - mPaddingTop;
|
||
|
|
final int bottom = getChildAt(0).getHeight();
|
||
|
|
final int maxY = Math.max(0, bottom - height);
|
||
|
|
final int scrollY = mScrollY;
|
||
|
|
dy = Math.max(0, Math.min(scrollY + dy, maxY)) - scrollY;
|
||
|
|
|
||
|
|
mScroller.startScroll(mScrollX, scrollY, 0, dy);
|
||
|
|
invalidate();
|
||
|
|
} else {
|
||
|
|
if (!mScroller.isFinished()) {
|
||
|
|
mScroller.abortAnimation();
|
||
|
|
}
|
||
|
|
scrollBy(dx, dy);
|
||
|
|
}
|
||
|
|
mLastScroll = AnimationUtils.currentAnimationTimeMillis();
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Like {@link #scrollTo}, but scroll smoothly instead of immediately.
|
||
|
|
*
|
||
|
|
* @param x the position where to scroll on the X axis
|
||
|
|
* @param y the position where to scroll on the Y axis
|
||
|
|
*/
|
||
|
|
public final void smoothScrollTo(int x, int y) {
|
||
|
|
smoothScrollBy(x - mScrollX, y - mScrollY);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* <p>The scroll range of a scroll view is the overall height of all of its
|
||
|
|
* children.</p>
|
||
|
|
*/
|
||
|
|
@Override
|
||
|
|
protected int computeVerticalScrollRange() {
|
||
|
|
final int count = getChildCount();
|
||
|
|
final int contentHeight = getHeight() - mPaddingBottom - mPaddingTop;
|
||
|
|
if (count == 0) {
|
||
|
|
return contentHeight;
|
||
|
|
}
|
||
|
|
|
||
|
|
int scrollRange = getChildAt(0).getBottom();
|
||
|
|
final int scrollY = mScrollY;
|
||
|
|
final int overscrollBottom = Math.max(0, scrollRange - contentHeight);
|
||
|
|
if (scrollY < 0) {
|
||
|
|
scrollRange -= scrollY;
|
||
|
|
} else if (scrollY > overscrollBottom) {
|
||
|
|
scrollRange += scrollY - overscrollBottom;
|
||
|
|
}
|
||
|
|
|
||
|
|
return scrollRange;
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
protected int computeVerticalScrollOffset() {
|
||
|
|
return Math.max(0, super.computeVerticalScrollOffset());
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
protected void measureChild(View child, int parentWidthMeasureSpec, int parentHeightMeasureSpec) {
|
||
|
|
ViewGroup.LayoutParams lp = child.getLayoutParams();
|
||
|
|
|
||
|
|
int childWidthMeasureSpec;
|
||
|
|
int childHeightMeasureSpec;
|
||
|
|
|
||
|
|
childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec, mPaddingLeft
|
||
|
|
+ mPaddingRight, lp.width);
|
||
|
|
|
||
|
|
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
|
||
|
|
|
||
|
|
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
protected void measureChildWithMargins(View child, int parentWidthMeasureSpec, int widthUsed,
|
||
|
|
int parentHeightMeasureSpec, int heightUsed) {
|
||
|
|
final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
|
||
|
|
|
||
|
|
final int childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec,
|
||
|
|
mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin
|
||
|
|
+ widthUsed, lp.width);
|
||
|
|
final int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
|
||
|
|
lp.topMargin + lp.bottomMargin, MeasureSpec.UNSPECIFIED);
|
||
|
|
|
||
|
|
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public void computeScroll() {
|
||
|
|
if (mScroller.computeScrollOffset()) {
|
||
|
|
// This is called at drawing time by ViewGroup. We don't want to
|
||
|
|
// re-show the scrollbars at this point, which scrollTo will do,
|
||
|
|
// so we replicate most of scrollTo here.
|
||
|
|
//
|
||
|
|
// It's a little odd to call onScrollChanged from inside the drawing.
|
||
|
|
//
|
||
|
|
// It is, except when you remember that computeScroll() is used to
|
||
|
|
// animate scrolling. So unless we want to defer the onScrollChanged()
|
||
|
|
// until the end of the animated scrolling, we don't really have a
|
||
|
|
// choice here.
|
||
|
|
//
|
||
|
|
// I agree. The alternative, which I think would be worse, is to post
|
||
|
|
// something and tell the subclasses later. This is bad because there
|
||
|
|
// will be a window where mScrollX/Y is different from what the app
|
||
|
|
// thinks it is.
|
||
|
|
//
|
||
|
|
int oldX = mScrollX;
|
||
|
|
int oldY = mScrollY;
|
||
|
|
int x = mScroller.getCurrX();
|
||
|
|
int y = mScroller.getCurrY();
|
||
|
|
|
||
|
|
if (oldX != x || oldY != y) {
|
||
|
|
overScrollBy(x - oldX, y - oldY, oldX, oldY, 0, getScrollRange(),
|
||
|
|
0, mOverflingDistance, false);
|
||
|
|
onScrollChanged(mScrollX, mScrollY, oldX, oldY);
|
||
|
|
|
||
|
|
final int range = getScrollRange();
|
||
|
|
final int overscrollMode = getOverScrollMode();
|
||
|
|
if (overscrollMode == OVER_SCROLL_ALWAYS ||
|
||
|
|
(overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0)) {
|
||
|
|
if (y < 0 && oldY >= 0) {
|
||
|
|
mEdgeGlowTop.onAbsorb((int) mScroller.getCurrVelocity());
|
||
|
|
} else if (y > range && oldY <= range) {
|
||
|
|
mEdgeGlowBottom.onAbsorb((int) mScroller.getCurrVelocity());
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
awakenScrollBars();
|
||
|
|
|
||
|
|
// Keep on drawing until the animation has finished.
|
||
|
|
postInvalidate();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Scrolls the view to the given child.
|
||
|
|
*
|
||
|
|
* @param child the View to scroll to
|
||
|
|
*/
|
||
|
|
private void scrollToChild(View child) {
|
||
|
|
child.getDrawingRect(mTempRect);
|
||
|
|
|
||
|
|
/* Offset from child's local coordinates to ScrollView coordinates */
|
||
|
|
offsetDescendantRectToMyCoords(child, mTempRect);
|
||
|
|
|
||
|
|
int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect);
|
||
|
|
|
||
|
|
if (scrollDelta != 0) {
|
||
|
|
scrollBy(0, scrollDelta);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* If rect is off screen, scroll just enough to get it (or at least the
|
||
|
|
* first screen size chunk of it) on screen.
|
||
|
|
*
|
||
|
|
* @param rect The rectangle.
|
||
|
|
* @param immediate True to scroll immediately without animation
|
||
|
|
* @return true if scrolling was performed
|
||
|
|
*/
|
||
|
|
private boolean scrollToChildRect(Rect rect, boolean immediate) {
|
||
|
|
final int delta = computeScrollDeltaToGetChildRectOnScreen(rect);
|
||
|
|
final boolean scroll = delta != 0;
|
||
|
|
if (scroll) {
|
||
|
|
if (immediate) {
|
||
|
|
scrollBy(0, delta);
|
||
|
|
} else {
|
||
|
|
smoothScrollBy(0, delta);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return scroll;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Compute the amount to scroll in the Y direction in order to get
|
||
|
|
* a rectangle completely on the screen (or, if taller than the screen,
|
||
|
|
* at least the first screen size chunk of it).
|
||
|
|
*
|
||
|
|
* @param rect The rect.
|
||
|
|
* @return The scroll delta.
|
||
|
|
*/
|
||
|
|
protected int computeScrollDeltaToGetChildRectOnScreen(Rect rect) {
|
||
|
|
if (getChildCount() == 0) return 0;
|
||
|
|
|
||
|
|
int height = getHeight();
|
||
|
|
int screenTop = getScrollY();
|
||
|
|
int screenBottom = screenTop + height;
|
||
|
|
|
||
|
|
int fadingEdge = getVerticalFadingEdgeLength();
|
||
|
|
|
||
|
|
// leave room for top fading edge as long as rect isn't at very top
|
||
|
|
if (rect.top > 0) {
|
||
|
|
screenTop += fadingEdge;
|
||
|
|
}
|
||
|
|
|
||
|
|
// leave room for bottom fading edge as long as rect isn't at very bottom
|
||
|
|
if (rect.bottom < getChildAt(0).getHeight()) {
|
||
|
|
screenBottom -= fadingEdge;
|
||
|
|
}
|
||
|
|
|
||
|
|
int scrollYDelta = 0;
|
||
|
|
|
||
|
|
if (rect.bottom > screenBottom && rect.top > screenTop) {
|
||
|
|
// need to move down to get it in view: move down just enough so
|
||
|
|
// that the entire rectangle is in view (or at least the first
|
||
|
|
// screen size chunk).
|
||
|
|
|
||
|
|
if (rect.height() > height) {
|
||
|
|
// just enough to get screen size chunk on
|
||
|
|
scrollYDelta += (rect.top - screenTop);
|
||
|
|
} else {
|
||
|
|
// get entire rect at bottom of screen
|
||
|
|
scrollYDelta += (rect.bottom - screenBottom);
|
||
|
|
}
|
||
|
|
|
||
|
|
// make sure we aren't scrolling beyond the end of our content
|
||
|
|
int bottom = getChildAt(0).getBottom();
|
||
|
|
int distanceToBottom = bottom - screenBottom;
|
||
|
|
scrollYDelta = Math.min(scrollYDelta, distanceToBottom);
|
||
|
|
|
||
|
|
} else if (rect.top < screenTop && rect.bottom < screenBottom) {
|
||
|
|
// need to move up to get it in view: move up just enough so that
|
||
|
|
// entire rectangle is in view (or at least the first screen
|
||
|
|
// size chunk of it).
|
||
|
|
|
||
|
|
if (rect.height() > height) {
|
||
|
|
// screen size chunk
|
||
|
|
scrollYDelta -= (screenBottom - rect.bottom);
|
||
|
|
} else {
|
||
|
|
// entire rect at top
|
||
|
|
scrollYDelta -= (screenTop - rect.top);
|
||
|
|
}
|
||
|
|
|
||
|
|
// make sure we aren't scrolling any further than the top our content
|
||
|
|
scrollYDelta = Math.max(scrollYDelta, -getScrollY());
|
||
|
|
}
|
||
|
|
return scrollYDelta;
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public void requestChildFocus(View child, View focused) {
|
||
|
|
if (!mScrollViewMovedFocus) {
|
||
|
|
if (!mIsLayoutDirty) {
|
||
|
|
scrollToChild(focused);
|
||
|
|
} else {
|
||
|
|
// The child may not be laid out yet, we can't compute the scroll yet
|
||
|
|
mChildToScrollTo = focused;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
super.requestChildFocus(child, focused);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/**
|
||
|
|
* When looking for focus in children of a scroll view, need to be a little
|
||
|
|
* more careful not to give focus to something that is scrolled off screen.
|
||
|
|
*
|
||
|
|
* This is more expensive than the default {@link android.view.ViewGroup}
|
||
|
|
* implementation, otherwise this behavior might have been made the default.
|
||
|
|
*/
|
||
|
|
@Override
|
||
|
|
protected boolean onRequestFocusInDescendants(int direction,
|
||
|
|
Rect previouslyFocusedRect) {
|
||
|
|
|
||
|
|
// convert from forward / backward notation to up / down / left / right
|
||
|
|
// (ugh).
|
||
|
|
if (direction == View.FOCUS_FORWARD) {
|
||
|
|
direction = View.FOCUS_DOWN;
|
||
|
|
} else if (direction == View.FOCUS_BACKWARD) {
|
||
|
|
direction = View.FOCUS_UP;
|
||
|
|
}
|
||
|
|
|
||
|
|
final View nextFocus = previouslyFocusedRect == null ?
|
||
|
|
FocusFinder.getInstance().findNextFocus(this, null, direction) :
|
||
|
|
FocusFinder.getInstance().findNextFocusFromRect(this,
|
||
|
|
previouslyFocusedRect, direction);
|
||
|
|
|
||
|
|
if (nextFocus == null) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (isOffScreen(nextFocus)) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
return nextFocus.requestFocus(direction, previouslyFocusedRect);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public boolean requestChildRectangleOnScreen(View child, Rect rectangle,
|
||
|
|
boolean immediate) {
|
||
|
|
// offset into coordinate space of this scroll view
|
||
|
|
rectangle.offset(child.getLeft() - child.getScrollX(),
|
||
|
|
child.getTop() - child.getScrollY());
|
||
|
|
|
||
|
|
return scrollToChildRect(rectangle, immediate);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public void requestLayout() {
|
||
|
|
mIsLayoutDirty = true;
|
||
|
|
super.requestLayout();
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
protected void onLayout(boolean changed, int l, int t, int r, int b) {
|
||
|
|
super.onLayout(changed, l, t, r, b);
|
||
|
|
mIsLayoutDirty = false;
|
||
|
|
// Give a child focus if it needs it
|
||
|
|
if (mChildToScrollTo != null && isViewDescendantOf(mChildToScrollTo, this)) {
|
||
|
|
scrollToChild(mChildToScrollTo);
|
||
|
|
}
|
||
|
|
mChildToScrollTo = null;
|
||
|
|
|
||
|
|
// Calling this with the present values causes it to re-clam them
|
||
|
|
scrollTo(mScrollX, mScrollY);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
|
||
|
|
super.onSizeChanged(w, h, oldw, oldh);
|
||
|
|
|
||
|
|
View currentFocused = findFocus();
|
||
|
|
if (null == currentFocused || this == currentFocused)
|
||
|
|
return;
|
||
|
|
|
||
|
|
// If the currently-focused view was visible on the screen when the
|
||
|
|
// screen was at the old height, then scroll the screen to make that
|
||
|
|
// view visible with the new screen height.
|
||
|
|
if (isWithinDeltaOfScreen(currentFocused, 0, oldh)) {
|
||
|
|
currentFocused.getDrawingRect(mTempRect);
|
||
|
|
offsetDescendantRectToMyCoords(currentFocused, mTempRect);
|
||
|
|
int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect);
|
||
|
|
doScrollY(scrollDelta);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Return true if child is an descendant of parent, (or equal to the parent).
|
||
|
|
*/
|
||
|
|
private boolean isViewDescendantOf(View child, View parent) {
|
||
|
|
if (child == parent) {
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
final ViewParent theParent = child.getParent();
|
||
|
|
return (theParent instanceof ViewGroup) && isViewDescendantOf((View) theParent, parent);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Fling the scroll view
|
||
|
|
*
|
||
|
|
* @param velocityY The initial velocity in the Y direction. Positive
|
||
|
|
* numbers mean that the finger/cursor is moving down the screen,
|
||
|
|
* which means we want to scroll towards the top.
|
||
|
|
*/
|
||
|
|
public void fling(int velocityY) {
|
||
|
|
if (getChildCount() > 0) {
|
||
|
|
int height = getHeight() - mPaddingBottom - mPaddingTop;
|
||
|
|
int bottom = getChildAt(0).getHeight();
|
||
|
|
|
||
|
|
mScroller.fling(mScrollX, mScrollY, 0, velocityY, 0, 0, 0,
|
||
|
|
Math.max(0, bottom - height), 0, height/2);
|
||
|
|
|
||
|
|
final boolean movingDown = velocityY > 0;
|
||
|
|
|
||
|
|
View newFocused =
|
||
|
|
findFocusableViewInMyBounds(movingDown, mScroller.getFinalY(), findFocus());
|
||
|
|
if (newFocused == null) {
|
||
|
|
newFocused = this;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (newFocused != findFocus()
|
||
|
|
&& newFocused.requestFocus(movingDown ? View.FOCUS_DOWN : View.FOCUS_UP)) {
|
||
|
|
mScrollViewMovedFocus = true;
|
||
|
|
mScrollViewMovedFocus = false;
|
||
|
|
}
|
||
|
|
|
||
|
|
invalidate();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* {@inheritDoc}
|
||
|
|
*
|
||
|
|
* <p>This version also clamps the scrolling to the bounds of our child.
|
||
|
|
*/
|
||
|
|
@Override
|
||
|
|
public void scrollTo(int x, int y) {
|
||
|
|
// we rely on the fact the View.scrollBy calls scrollTo.
|
||
|
|
if (getChildCount() > 0) {
|
||
|
|
View child = getChildAt(0);
|
||
|
|
x = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth());
|
||
|
|
y = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight());
|
||
|
|
if (x != mScrollX || y != mScrollY) {
|
||
|
|
super.scrollTo(x, y);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public void setOverScrollMode(int mode) {
|
||
|
|
if (mode != OVER_SCROLL_NEVER) {
|
||
|
|
if (mEdgeGlowTop == null) {
|
||
|
|
final Resources res = getContext().getResources();
|
||
|
|
final Drawable edge = res.getDrawable(R.drawable.overscroll_edge);
|
||
|
|
final Drawable glow = res.getDrawable(R.drawable.overscroll_glow);
|
||
|
|
mEdgeGlowTop = new EdgeGlow(edge, glow);
|
||
|
|
mEdgeGlowBottom = new EdgeGlow(edge, glow);
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
mEdgeGlowTop = null;
|
||
|
|
mEdgeGlowBottom = null;
|
||
|
|
}
|
||
|
|
super.setOverScrollMode(mode);
|
||
|
|
}
|
||
|
|
|
||
|
|
@Override
|
||
|
|
public void draw(Canvas canvas) {
|
||
|
|
super.draw(canvas);
|
||
|
|
if (mEdgeGlowTop != null) {
|
||
|
|
final int scrollY = mScrollY;
|
||
|
|
if (!mEdgeGlowTop.isFinished()) {
|
||
|
|
final int restoreCount = canvas.save();
|
||
|
|
final int width = getWidth();
|
||
|
|
|
||
|
|
canvas.translate(-width / 2, Math.min(0, scrollY));
|
||
|
|
mEdgeGlowTop.setSize(width * 2, getHeight());
|
||
|
|
if (mEdgeGlowTop.draw(canvas)) {
|
||
|
|
invalidate();
|
||
|
|
}
|
||
|
|
canvas.restoreToCount(restoreCount);
|
||
|
|
}
|
||
|
|
if (!mEdgeGlowBottom.isFinished()) {
|
||
|
|
final int restoreCount = canvas.save();
|
||
|
|
final int width = getWidth();
|
||
|
|
final int height = getHeight();
|
||
|
|
|
||
|
|
canvas.translate(-width / 2, Math.max(getScrollRange(), scrollY) + height);
|
||
|
|
canvas.rotate(180, width, 0);
|
||
|
|
mEdgeGlowBottom.setSize(width * 2, height);
|
||
|
|
if (mEdgeGlowBottom.draw(canvas)) {
|
||
|
|
invalidate();
|
||
|
|
}
|
||
|
|
canvas.restoreToCount(restoreCount);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private int clamp(int n, int my, int child) {
|
||
|
|
if (my >= child || n < 0) {
|
||
|
|
/* my >= child is this case:
|
||
|
|
* |--------------- me ---------------|
|
||
|
|
* |------ child ------|
|
||
|
|
* or
|
||
|
|
* |--------------- me ---------------|
|
||
|
|
* |------ child ------|
|
||
|
|
* or
|
||
|
|
* |--------------- me ---------------|
|
||
|
|
* |------ child ------|
|
||
|
|
*
|
||
|
|
* n < 0 is this case:
|
||
|
|
* |------ me ------|
|
||
|
|
* |-------- child --------|
|
||
|
|
* |-- mScrollX --|
|
||
|
|
*/
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
if ((my+n) > child) {
|
||
|
|
/* this case:
|
||
|
|
* |------ me ------|
|
||
|
|
* |------ child ------|
|
||
|
|
* |-- mScrollX --|
|
||
|
|
*/
|
||
|
|
return child-my;
|
||
|
|
}
|
||
|
|
return n;
|
||
|
|
}
|
||
|
|
}
|