850 lines
30 KiB
Java
850 lines
30 KiB
Java
/*
|
|
* Copyright (C) 2010 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
package android.widget;
|
|
|
|
import android.content.Context;
|
|
import android.hardware.SensorManager;
|
|
import android.util.FloatMath;
|
|
import android.view.ViewConfiguration;
|
|
import android.view.animation.AnimationUtils;
|
|
import android.view.animation.Interpolator;
|
|
|
|
/**
|
|
* This class encapsulates scrolling with the ability to overshoot the bounds
|
|
* of a scrolling operation. This class is a drop-in replacement for
|
|
* {@link android.widget.Scroller} in most cases.
|
|
*/
|
|
public class OverScroller {
|
|
private int mMode;
|
|
|
|
private MagneticOverScroller mScrollerX;
|
|
private MagneticOverScroller mScrollerY;
|
|
|
|
private final Interpolator mInterpolator;
|
|
|
|
private static final int DEFAULT_DURATION = 250;
|
|
private static final int SCROLL_MODE = 0;
|
|
private static final int FLING_MODE = 1;
|
|
|
|
/**
|
|
* Creates an OverScroller with a viscous fluid scroll interpolator.
|
|
* @param context
|
|
*/
|
|
public OverScroller(Context context) {
|
|
this(context, null);
|
|
}
|
|
|
|
/**
|
|
* Creates an OverScroller with default edge bounce coefficients.
|
|
* @param context The context of this application.
|
|
* @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will
|
|
* be used.
|
|
*/
|
|
public OverScroller(Context context, Interpolator interpolator) {
|
|
this(context, interpolator, MagneticOverScroller.DEFAULT_BOUNCE_COEFFICIENT,
|
|
MagneticOverScroller.DEFAULT_BOUNCE_COEFFICIENT);
|
|
}
|
|
|
|
/**
|
|
* Creates an OverScroller.
|
|
* @param context The context of this application.
|
|
* @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will
|
|
* be used.
|
|
* @param bounceCoefficientX A value between 0 and 1 that will determine the proportion of the
|
|
* velocity which is preserved in the bounce when the horizontal edge is reached. A null value
|
|
* means no bounce.
|
|
* @param bounceCoefficientY Same as bounceCoefficientX but for the vertical direction.
|
|
*/
|
|
public OverScroller(Context context, Interpolator interpolator,
|
|
float bounceCoefficientX, float bounceCoefficientY) {
|
|
mInterpolator = interpolator;
|
|
mScrollerX = new MagneticOverScroller();
|
|
mScrollerY = new MagneticOverScroller();
|
|
MagneticOverScroller.initializeFromContext(context);
|
|
|
|
mScrollerX.setBounceCoefficient(bounceCoefficientX);
|
|
mScrollerY.setBounceCoefficient(bounceCoefficientY);
|
|
}
|
|
|
|
/**
|
|
*
|
|
* Returns whether the scroller has finished scrolling.
|
|
*
|
|
* @return True if the scroller has finished scrolling, false otherwise.
|
|
*/
|
|
public final boolean isFinished() {
|
|
return mScrollerX.mFinished && mScrollerY.mFinished;
|
|
}
|
|
|
|
/**
|
|
* Force the finished field to a particular value. Contrary to
|
|
* {@link #abortAnimation()}, forcing the animation to finished
|
|
* does NOT cause the scroller to move to the final x and y
|
|
* position.
|
|
*
|
|
* @param finished The new finished value.
|
|
*/
|
|
public final void forceFinished(boolean finished) {
|
|
mScrollerX.mFinished = mScrollerY.mFinished = finished;
|
|
}
|
|
|
|
/**
|
|
* Returns the current X offset in the scroll.
|
|
*
|
|
* @return The new X offset as an absolute distance from the origin.
|
|
*/
|
|
public final int getCurrX() {
|
|
return mScrollerX.mCurrentPosition;
|
|
}
|
|
|
|
/**
|
|
* Returns the current Y offset in the scroll.
|
|
*
|
|
* @return The new Y offset as an absolute distance from the origin.
|
|
*/
|
|
public final int getCurrY() {
|
|
return mScrollerY.mCurrentPosition;
|
|
}
|
|
|
|
/**
|
|
* @hide
|
|
* Returns the current velocity.
|
|
*
|
|
* @return The original velocity less the deceleration, norm of the X and Y velocity vector.
|
|
*/
|
|
public float getCurrVelocity() {
|
|
float squaredNorm = mScrollerX.mCurrVelocity * mScrollerX.mCurrVelocity;
|
|
squaredNorm += mScrollerY.mCurrVelocity * mScrollerY.mCurrVelocity;
|
|
return FloatMath.sqrt(squaredNorm);
|
|
}
|
|
|
|
/**
|
|
* Returns the start X offset in the scroll.
|
|
*
|
|
* @return The start X offset as an absolute distance from the origin.
|
|
*/
|
|
public final int getStartX() {
|
|
return mScrollerX.mStart;
|
|
}
|
|
|
|
/**
|
|
* Returns the start Y offset in the scroll.
|
|
*
|
|
* @return The start Y offset as an absolute distance from the origin.
|
|
*/
|
|
public final int getStartY() {
|
|
return mScrollerY.mStart;
|
|
}
|
|
|
|
/**
|
|
* Returns where the scroll will end. Valid only for "fling" scrolls.
|
|
*
|
|
* @return The final X offset as an absolute distance from the origin.
|
|
*/
|
|
public final int getFinalX() {
|
|
return mScrollerX.mFinal;
|
|
}
|
|
|
|
/**
|
|
* Returns where the scroll will end. Valid only for "fling" scrolls.
|
|
*
|
|
* @return The final Y offset as an absolute distance from the origin.
|
|
*/
|
|
public final int getFinalY() {
|
|
return mScrollerY.mFinal;
|
|
}
|
|
|
|
/**
|
|
* Returns how long the scroll event will take, in milliseconds.
|
|
*
|
|
* @return The duration of the scroll in milliseconds.
|
|
*
|
|
* @hide Pending removal once nothing depends on it
|
|
* @deprecated OverScrollers don't necessarily have a fixed duration.
|
|
* This function will lie to the best of its ability.
|
|
*/
|
|
public final int getDuration() {
|
|
return Math.max(mScrollerX.mDuration, mScrollerY.mDuration);
|
|
}
|
|
|
|
/**
|
|
* Extend the scroll animation. This allows a running animation to scroll
|
|
* further and longer, when used with {@link #setFinalX(int)} or {@link #setFinalY(int)}.
|
|
*
|
|
* @param extend Additional time to scroll in milliseconds.
|
|
* @see #setFinalX(int)
|
|
* @see #setFinalY(int)
|
|
*
|
|
* @hide Pending removal once nothing depends on it
|
|
* @deprecated OverScrollers don't necessarily have a fixed duration.
|
|
* Instead of setting a new final position and extending
|
|
* the duration of an existing scroll, use startScroll
|
|
* to begin a new animation.
|
|
*/
|
|
public void extendDuration(int extend) {
|
|
mScrollerX.extendDuration(extend);
|
|
mScrollerY.extendDuration(extend);
|
|
}
|
|
|
|
/**
|
|
* Sets the final position (X) for this scroller.
|
|
*
|
|
* @param newX The new X offset as an absolute distance from the origin.
|
|
* @see #extendDuration(int)
|
|
* @see #setFinalY(int)
|
|
*
|
|
* @hide Pending removal once nothing depends on it
|
|
* @deprecated OverScroller's final position may change during an animation.
|
|
* Instead of setting a new final position and extending
|
|
* the duration of an existing scroll, use startScroll
|
|
* to begin a new animation.
|
|
*/
|
|
public void setFinalX(int newX) {
|
|
mScrollerX.setFinalPosition(newX);
|
|
}
|
|
|
|
/**
|
|
* Sets the final position (Y) for this scroller.
|
|
*
|
|
* @param newY The new Y offset as an absolute distance from the origin.
|
|
* @see #extendDuration(int)
|
|
* @see #setFinalX(int)
|
|
*
|
|
* @hide Pending removal once nothing depends on it
|
|
* @deprecated OverScroller's final position may change during an animation.
|
|
* Instead of setting a new final position and extending
|
|
* the duration of an existing scroll, use startScroll
|
|
* to begin a new animation.
|
|
*/
|
|
public void setFinalY(int newY) {
|
|
mScrollerY.setFinalPosition(newY);
|
|
}
|
|
|
|
/**
|
|
* Call this when you want to know the new location. If it returns true, the
|
|
* animation is not yet finished.
|
|
*/
|
|
public boolean computeScrollOffset() {
|
|
if (isFinished()) {
|
|
return false;
|
|
}
|
|
|
|
switch (mMode) {
|
|
case SCROLL_MODE:
|
|
long time = AnimationUtils.currentAnimationTimeMillis();
|
|
// Any scroller can be used for time, since they were started
|
|
// together in scroll mode. We use X here.
|
|
final long elapsedTime = time - mScrollerX.mStartTime;
|
|
|
|
final int duration = mScrollerX.mDuration;
|
|
if (elapsedTime < duration) {
|
|
float q = (float) (elapsedTime) / duration;
|
|
|
|
if (mInterpolator == null)
|
|
q = Scroller.viscousFluid(q);
|
|
else
|
|
q = mInterpolator.getInterpolation(q);
|
|
|
|
mScrollerX.updateScroll(q);
|
|
mScrollerY.updateScroll(q);
|
|
} else {
|
|
abortAnimation();
|
|
}
|
|
break;
|
|
|
|
case FLING_MODE:
|
|
if (!mScrollerX.mFinished) {
|
|
if (!mScrollerX.update()) {
|
|
if (!mScrollerX.continueWhenFinished()) {
|
|
mScrollerX.finish();
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!mScrollerY.mFinished) {
|
|
if (!mScrollerY.update()) {
|
|
if (!mScrollerY.continueWhenFinished()) {
|
|
mScrollerY.finish();
|
|
}
|
|
}
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Start scrolling by providing a starting point and the distance to travel.
|
|
* The scroll will use the default value of 250 milliseconds for the
|
|
* duration.
|
|
*
|
|
* @param startX Starting horizontal scroll offset in pixels. Positive
|
|
* numbers will scroll the content to the left.
|
|
* @param startY Starting vertical scroll offset in pixels. Positive numbers
|
|
* will scroll the content up.
|
|
* @param dx Horizontal distance to travel. Positive numbers will scroll the
|
|
* content to the left.
|
|
* @param dy Vertical distance to travel. Positive numbers will scroll the
|
|
* content up.
|
|
*/
|
|
public void startScroll(int startX, int startY, int dx, int dy) {
|
|
startScroll(startX, startY, dx, dy, DEFAULT_DURATION);
|
|
}
|
|
|
|
/**
|
|
* Start scrolling by providing a starting point and the distance to travel.
|
|
*
|
|
* @param startX Starting horizontal scroll offset in pixels. Positive
|
|
* numbers will scroll the content to the left.
|
|
* @param startY Starting vertical scroll offset in pixels. Positive numbers
|
|
* will scroll the content up.
|
|
* @param dx Horizontal distance to travel. Positive numbers will scroll the
|
|
* content to the left.
|
|
* @param dy Vertical distance to travel. Positive numbers will scroll the
|
|
* content up.
|
|
* @param duration Duration of the scroll in milliseconds.
|
|
*/
|
|
public void startScroll(int startX, int startY, int dx, int dy, int duration) {
|
|
mMode = SCROLL_MODE;
|
|
mScrollerX.startScroll(startX, dx, duration);
|
|
mScrollerY.startScroll(startY, dy, duration);
|
|
}
|
|
|
|
/**
|
|
* Call this when you want to 'spring back' into a valid coordinate range.
|
|
*
|
|
* @param startX Starting X coordinate
|
|
* @param startY Starting Y coordinate
|
|
* @param minX Minimum valid X value
|
|
* @param maxX Maximum valid X value
|
|
* @param minY Minimum valid Y value
|
|
* @param maxY Minimum valid Y value
|
|
* @return true if a springback was initiated, false if startX and startY were
|
|
* already within the valid range.
|
|
*/
|
|
public boolean springBack(int startX, int startY, int minX, int maxX, int minY, int maxY) {
|
|
mMode = FLING_MODE;
|
|
|
|
// Make sure both methods are called.
|
|
final boolean spingbackX = mScrollerX.springback(startX, minX, maxX);
|
|
final boolean spingbackY = mScrollerY.springback(startY, minY, maxY);
|
|
return spingbackX || spingbackY;
|
|
}
|
|
|
|
public void fling(int startX, int startY, int velocityX, int velocityY,
|
|
int minX, int maxX, int minY, int maxY) {
|
|
fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY, 0, 0);
|
|
}
|
|
|
|
/**
|
|
* Start scrolling based on a fling gesture. The distance traveled will
|
|
* depend on the initial velocity of the fling.
|
|
*
|
|
* @param startX Starting point of the scroll (X)
|
|
* @param startY Starting point of the scroll (Y)
|
|
* @param velocityX Initial velocity of the fling (X) measured in pixels per
|
|
* second.
|
|
* @param velocityY Initial velocity of the fling (Y) measured in pixels per
|
|
* second
|
|
* @param minX Minimum X value. The scroller will not scroll past this point
|
|
* unless overX > 0. If overfling is allowed, it will use minX as
|
|
* a springback boundary.
|
|
* @param maxX Maximum X value. The scroller will not scroll past this point
|
|
* unless overX > 0. If overfling is allowed, it will use maxX as
|
|
* a springback boundary.
|
|
* @param minY Minimum Y value. The scroller will not scroll past this point
|
|
* unless overY > 0. If overfling is allowed, it will use minY as
|
|
* a springback boundary.
|
|
* @param maxY Maximum Y value. The scroller will not scroll past this point
|
|
* unless overY > 0. If overfling is allowed, it will use maxY as
|
|
* a springback boundary.
|
|
* @param overX Overfling range. If > 0, horizontal overfling in either
|
|
* direction will be possible.
|
|
* @param overY Overfling range. If > 0, vertical overfling in either
|
|
* direction will be possible.
|
|
*/
|
|
public void fling(int startX, int startY, int velocityX, int velocityY,
|
|
int minX, int maxX, int minY, int maxY, int overX, int overY) {
|
|
mMode = FLING_MODE;
|
|
mScrollerX.fling(startX, velocityX, minX, maxX, overX);
|
|
mScrollerY.fling(startY, velocityY, minY, maxY, overY);
|
|
}
|
|
|
|
/**
|
|
* Notify the scroller that we've reached a horizontal boundary.
|
|
* Normally the information to handle this will already be known
|
|
* when the animation is started, such as in a call to one of the
|
|
* fling functions. However there are cases where this cannot be known
|
|
* in advance. This function will transition the current motion and
|
|
* animate from startX to finalX as appropriate.
|
|
*
|
|
* @param startX Starting/current X position
|
|
* @param finalX Desired final X position
|
|
* @param overX Magnitude of overscroll allowed. This should be the maximum
|
|
* desired distance from finalX. Absolute value - must be positive.
|
|
*/
|
|
public void notifyHorizontalEdgeReached(int startX, int finalX, int overX) {
|
|
mScrollerX.notifyEdgeReached(startX, finalX, overX);
|
|
}
|
|
|
|
/**
|
|
* Notify the scroller that we've reached a vertical boundary.
|
|
* Normally the information to handle this will already be known
|
|
* when the animation is started, such as in a call to one of the
|
|
* fling functions. However there are cases where this cannot be known
|
|
* in advance. This function will animate a parabolic motion from
|
|
* startY to finalY.
|
|
*
|
|
* @param startY Starting/current Y position
|
|
* @param finalY Desired final Y position
|
|
* @param overY Magnitude of overscroll allowed. This should be the maximum
|
|
* desired distance from finalY.
|
|
*/
|
|
public void notifyVerticalEdgeReached(int startY, int finalY, int overY) {
|
|
mScrollerY.notifyEdgeReached(startY, finalY, overY);
|
|
}
|
|
|
|
/**
|
|
* Returns whether the current Scroller is currently returning to a valid position.
|
|
* Valid bounds were provided by the
|
|
* {@link #fling(int, int, int, int, int, int, int, int, int, int)} method.
|
|
*
|
|
* One should check this value before calling
|
|
* {@link #startScroll(int, int, int, int)} as the interpolation currently in progress
|
|
* to restore a valid position will then be stopped. The caller has to take into account
|
|
* the fact that the started scroll will start from an overscrolled position.
|
|
*
|
|
* @return true when the current position is overscrolled and in the process of
|
|
* interpolating back to a valid value.
|
|
*/
|
|
public boolean isOverScrolled() {
|
|
return ((!mScrollerX.mFinished &&
|
|
mScrollerX.mState != MagneticOverScroller.TO_EDGE) ||
|
|
(!mScrollerY.mFinished &&
|
|
mScrollerY.mState != MagneticOverScroller.TO_EDGE));
|
|
}
|
|
|
|
/**
|
|
* Stops the animation. Contrary to {@link #forceFinished(boolean)},
|
|
* aborting the animating causes the scroller to move to the final x and y
|
|
* positions.
|
|
*
|
|
* @see #forceFinished(boolean)
|
|
*/
|
|
public void abortAnimation() {
|
|
mScrollerX.finish();
|
|
mScrollerY.finish();
|
|
}
|
|
|
|
/**
|
|
* Returns the time elapsed since the beginning of the scrolling.
|
|
*
|
|
* @return The elapsed time in milliseconds.
|
|
*
|
|
* @hide
|
|
*/
|
|
public int timePassed() {
|
|
final long time = AnimationUtils.currentAnimationTimeMillis();
|
|
final long startTime = Math.min(mScrollerX.mStartTime, mScrollerY.mStartTime);
|
|
return (int) (time - startTime);
|
|
}
|
|
|
|
static class MagneticOverScroller {
|
|
// Initial position
|
|
int mStart;
|
|
|
|
// Current position
|
|
int mCurrentPosition;
|
|
|
|
// Final position
|
|
int mFinal;
|
|
|
|
// Initial velocity
|
|
int mVelocity;
|
|
|
|
// Current velocity
|
|
float mCurrVelocity;
|
|
|
|
// Constant current deceleration
|
|
float mDeceleration;
|
|
|
|
// Animation starting time, in system milliseconds
|
|
long mStartTime;
|
|
|
|
// Animation duration, in milliseconds
|
|
int mDuration;
|
|
|
|
// Whether the animation is currently in progress
|
|
boolean mFinished;
|
|
|
|
// Constant gravity value, used to scale deceleration
|
|
static float GRAVITY;
|
|
|
|
static void initializeFromContext(Context context) {
|
|
final float ppi = context.getResources().getDisplayMetrics().density * 160.0f;
|
|
GRAVITY = SensorManager.GRAVITY_EARTH // g (m/s^2)
|
|
* 39.37f // inch/meter
|
|
* ppi // pixels per inch
|
|
* ViewConfiguration.getScrollFriction();
|
|
}
|
|
|
|
private static final int TO_EDGE = 0;
|
|
private static final int TO_BOUNDARY = 1;
|
|
private static final int TO_BOUNCE = 2;
|
|
|
|
private int mState = TO_EDGE;
|
|
|
|
// The allowed overshot distance before boundary is reached.
|
|
private int mOver;
|
|
|
|
// Duration in milliseconds to go back from edge to edge. Springback is half of it.
|
|
private static final int OVERSCROLL_SPRINGBACK_DURATION = 200;
|
|
|
|
// Oscillation period
|
|
private static final float TIME_COEF =
|
|
1000.0f * (float) Math.PI / OVERSCROLL_SPRINGBACK_DURATION;
|
|
|
|
// If the velocity is smaller than this value, no bounce is triggered
|
|
// when the edge limits are reached (would result in a zero pixels
|
|
// displacement anyway).
|
|
private static final float MINIMUM_VELOCITY_FOR_BOUNCE = Float.MAX_VALUE;//140.0f;
|
|
|
|
// Proportion of the velocity that is preserved when the edge is reached.
|
|
private static final float DEFAULT_BOUNCE_COEFFICIENT = 0.16f;
|
|
|
|
private float mBounceCoefficient = DEFAULT_BOUNCE_COEFFICIENT;
|
|
|
|
MagneticOverScroller() {
|
|
mFinished = true;
|
|
}
|
|
|
|
void updateScroll(float q) {
|
|
mCurrentPosition = mStart + Math.round(q * (mFinal - mStart));
|
|
}
|
|
|
|
/*
|
|
* Get a signed deceleration that will reduce the velocity.
|
|
*/
|
|
static float getDeceleration(int velocity) {
|
|
return velocity > 0 ? -GRAVITY : GRAVITY;
|
|
}
|
|
|
|
/*
|
|
* Returns the time (in milliseconds) it will take to go from start to end.
|
|
*/
|
|
static int computeDuration(int start, int end, float initialVelocity, float deceleration) {
|
|
final int distance = start - end;
|
|
final float discriminant = initialVelocity * initialVelocity - 2.0f * deceleration
|
|
* distance;
|
|
if (discriminant >= 0.0f) {
|
|
float delta = (float) Math.sqrt(discriminant);
|
|
if (deceleration < 0.0f) {
|
|
delta = -delta;
|
|
}
|
|
return (int) (1000.0f * (-initialVelocity - delta) / deceleration);
|
|
}
|
|
|
|
// End position can not be reached
|
|
return 0;
|
|
}
|
|
|
|
void startScroll(int start, int distance, int duration) {
|
|
mFinished = false;
|
|
|
|
mStart = start;
|
|
mFinal = start + distance;
|
|
|
|
mStartTime = AnimationUtils.currentAnimationTimeMillis();
|
|
mDuration = duration;
|
|
|
|
// Unused
|
|
mDeceleration = 0.0f;
|
|
mVelocity = 0;
|
|
}
|
|
|
|
void fling(int start, int velocity, int min, int max) {
|
|
mFinished = false;
|
|
|
|
mStart = start;
|
|
mStartTime = AnimationUtils.currentAnimationTimeMillis();
|
|
|
|
mVelocity = velocity;
|
|
|
|
mDeceleration = getDeceleration(velocity);
|
|
|
|
// A start from an invalid position immediately brings back to a valid position
|
|
if (mStart < min) {
|
|
mDuration = 0;
|
|
mFinal = min;
|
|
return;
|
|
}
|
|
|
|
if (mStart > max) {
|
|
mDuration = 0;
|
|
mFinal = max;
|
|
return;
|
|
}
|
|
|
|
// Duration are expressed in milliseconds
|
|
mDuration = (int) (-1000.0f * velocity / mDeceleration);
|
|
|
|
mFinal = start - Math.round((velocity * velocity) / (2.0f * mDeceleration));
|
|
|
|
// Clamp to a valid final position
|
|
if (mFinal < min) {
|
|
mFinal = min;
|
|
mDuration = computeDuration(mStart, min, mVelocity, mDeceleration);
|
|
}
|
|
|
|
if (mFinal > max) {
|
|
mFinal = max;
|
|
mDuration = computeDuration(mStart, max, mVelocity, mDeceleration);
|
|
}
|
|
}
|
|
|
|
void finish() {
|
|
mCurrentPosition = mFinal;
|
|
// Not reset since WebView relies on this value for fast fling.
|
|
// mCurrVelocity = 0.0f;
|
|
mFinished = true;
|
|
}
|
|
|
|
void setFinalPosition(int position) {
|
|
mFinal = position;
|
|
mFinished = false;
|
|
}
|
|
|
|
void extendDuration(int extend) {
|
|
final long time = AnimationUtils.currentAnimationTimeMillis();
|
|
final int elapsedTime = (int) (time - mStartTime);
|
|
mDuration = elapsedTime + extend;
|
|
mFinished = false;
|
|
}
|
|
|
|
void setBounceCoefficient(float coefficient) {
|
|
mBounceCoefficient = coefficient;
|
|
}
|
|
|
|
boolean springback(int start, int min, int max) {
|
|
mFinished = true;
|
|
|
|
mStart = start;
|
|
mVelocity = 0;
|
|
|
|
mStartTime = AnimationUtils.currentAnimationTimeMillis();
|
|
mDuration = 0;
|
|
|
|
if (start < min) {
|
|
startSpringback(start, min, false);
|
|
} else if (start > max) {
|
|
startSpringback(start, max, true);
|
|
}
|
|
|
|
return !mFinished;
|
|
}
|
|
|
|
private void startSpringback(int start, int end, boolean positive) {
|
|
mFinished = false;
|
|
mState = TO_BOUNCE;
|
|
mStart = mFinal = end;
|
|
mDuration = OVERSCROLL_SPRINGBACK_DURATION;
|
|
mStartTime -= OVERSCROLL_SPRINGBACK_DURATION / 2;
|
|
mVelocity = (int) (Math.abs(end - start) * TIME_COEF * (positive ? 1.0 : -1.0f));
|
|
}
|
|
|
|
void fling(int start, int velocity, int min, int max, int over) {
|
|
mState = TO_EDGE;
|
|
mOver = over;
|
|
|
|
mFinished = false;
|
|
|
|
mStart = start;
|
|
mStartTime = AnimationUtils.currentAnimationTimeMillis();
|
|
|
|
mVelocity = velocity;
|
|
|
|
mDeceleration = getDeceleration(velocity);
|
|
|
|
// Duration are expressed in milliseconds
|
|
mDuration = (int) (-1000.0f * velocity / mDeceleration);
|
|
|
|
mFinal = start - Math.round((velocity * velocity) / (2.0f * mDeceleration));
|
|
|
|
// Clamp to a valid final position
|
|
if (mFinal < min) {
|
|
mFinal = min;
|
|
mDuration = computeDuration(mStart, min, mVelocity, mDeceleration);
|
|
}
|
|
|
|
if (mFinal > max) {
|
|
mFinal = max;
|
|
mDuration = computeDuration(mStart, max, mVelocity, mDeceleration);
|
|
}
|
|
|
|
if (start > max) {
|
|
if (start >= max + over) {
|
|
springback(max + over, min, max);
|
|
} else {
|
|
if (velocity <= 0) {
|
|
springback(start, min, max);
|
|
} else {
|
|
long time = AnimationUtils.currentAnimationTimeMillis();
|
|
final double durationSinceEdge =
|
|
Math.atan((start-max) * TIME_COEF / velocity) / TIME_COEF;
|
|
mStartTime = (int) (time - 1000.0f * durationSinceEdge);
|
|
|
|
// Simulate a bounce that started from edge
|
|
mStart = max;
|
|
|
|
mVelocity = (int) (velocity / Math.cos(durationSinceEdge * TIME_COEF));
|
|
|
|
onEdgeReached();
|
|
}
|
|
}
|
|
} else {
|
|
if (start < min) {
|
|
if (start <= min - over) {
|
|
springback(min - over, min, max);
|
|
} else {
|
|
if (velocity >= 0) {
|
|
springback(start, min, max);
|
|
} else {
|
|
long time = AnimationUtils.currentAnimationTimeMillis();
|
|
final double durationSinceEdge =
|
|
Math.atan((start-min) * TIME_COEF / velocity) / TIME_COEF;
|
|
mStartTime = (int) (time - 1000.0f * durationSinceEdge);
|
|
|
|
// Simulate a bounce that started from edge
|
|
mStart = min;
|
|
|
|
mVelocity = (int) (velocity / Math.cos(durationSinceEdge * TIME_COEF));
|
|
|
|
onEdgeReached();
|
|
}
|
|
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void notifyEdgeReached(int start, int end, int over) {
|
|
mDeceleration = getDeceleration(mVelocity);
|
|
|
|
// Local time, used to compute edge crossing time.
|
|
float timeCurrent = mCurrVelocity / mDeceleration;
|
|
final int distance = end - start;
|
|
float timeEdge = -(float) Math.sqrt((2.0f * distance / mDeceleration)
|
|
+ (timeCurrent * timeCurrent));
|
|
|
|
mVelocity = (int) (mDeceleration * timeEdge);
|
|
|
|
// Simulate a symmetric bounce that started from edge
|
|
mStart = end;
|
|
|
|
mOver = over;
|
|
|
|
long time = AnimationUtils.currentAnimationTimeMillis();
|
|
mStartTime = (int) (time - 1000.0f * (timeCurrent - timeEdge));
|
|
|
|
onEdgeReached();
|
|
}
|
|
|
|
private void onEdgeReached() {
|
|
// mStart, mVelocity and mStartTime were adjusted to their values when edge was reached.
|
|
final float distance = mVelocity / TIME_COEF;
|
|
|
|
if (Math.abs(distance) < mOver) {
|
|
// Spring force will bring us back to final position
|
|
mState = TO_BOUNCE;
|
|
mFinal = mStart;
|
|
mDuration = OVERSCROLL_SPRINGBACK_DURATION;
|
|
} else {
|
|
// Velocity is too high, we will hit the boundary limit
|
|
mState = TO_BOUNDARY;
|
|
int over = mVelocity > 0 ? mOver : -mOver;
|
|
mFinal = mStart + over;
|
|
mDuration = (int) (1000.0f * Math.asin(over / distance) / TIME_COEF);
|
|
}
|
|
}
|
|
|
|
boolean continueWhenFinished() {
|
|
switch (mState) {
|
|
case TO_EDGE:
|
|
// Duration from start to null velocity
|
|
int duration = (int) (-1000.0f * mVelocity / mDeceleration);
|
|
if (mDuration < duration) {
|
|
// If the animation was clamped, we reached the edge
|
|
mStart = mFinal;
|
|
// Speed when edge was reached
|
|
mVelocity = (int) (mVelocity + mDeceleration * mDuration / 1000.0f);
|
|
mStartTime += mDuration;
|
|
onEdgeReached();
|
|
} else {
|
|
// Normal stop, no need to continue
|
|
return false;
|
|
}
|
|
break;
|
|
case TO_BOUNDARY:
|
|
mStartTime += mDuration;
|
|
startSpringback(mFinal, mFinal - (mVelocity > 0 ? mOver:-mOver), mVelocity > 0);
|
|
break;
|
|
case TO_BOUNCE:
|
|
//mVelocity = (int) (mVelocity * BOUNCE_COEFFICIENT);
|
|
mVelocity = (int) (mVelocity * mBounceCoefficient);
|
|
if (Math.abs(mVelocity) < MINIMUM_VELOCITY_FOR_BOUNCE) {
|
|
return false;
|
|
}
|
|
mStartTime += mDuration;
|
|
break;
|
|
}
|
|
|
|
update();
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Update the current position and velocity for current time. Returns
|
|
* true if update has been done and false if animation duration has been
|
|
* reached.
|
|
*/
|
|
boolean update() {
|
|
final long time = AnimationUtils.currentAnimationTimeMillis();
|
|
final long duration = time - mStartTime;
|
|
|
|
if (duration > mDuration) {
|
|
return false;
|
|
}
|
|
|
|
double distance;
|
|
final float t = duration / 1000.0f;
|
|
if (mState == TO_EDGE) {
|
|
mCurrVelocity = mVelocity + mDeceleration * t;
|
|
distance = mVelocity * t + mDeceleration * t * t / 2.0f;
|
|
} else {
|
|
final float d = t * TIME_COEF;
|
|
mCurrVelocity = mVelocity * (float)Math.cos(d);
|
|
distance = mVelocity / TIME_COEF * Math.sin(d);
|
|
}
|
|
|
|
mCurrentPosition = mStart + (int) distance;
|
|
return true;
|
|
}
|
|
}
|
|
}
|