* A ViewGroup is a special view that can contain other views
* (called children.) The view group is the base class for layouts and views
* containers. This class also defines the
* {@link android.view.ViewGroup.LayoutParams} class which serves as the base
* class for layouts parameters.
*
* Also see {@link LayoutParams} for layout attributes. *
* * @attr ref android.R.styleable#ViewGroup_clipChildren * @attr ref android.R.styleable#ViewGroup_clipToPadding * @attr ref android.R.styleable#ViewGroup_layoutAnimation * @attr ref android.R.styleable#ViewGroup_animationCache * @attr ref android.R.styleable#ViewGroup_persistentDrawingCache * @attr ref android.R.styleable#ViewGroup_alwaysDrawnWithCache * @attr ref android.R.styleable#ViewGroup_addStatesFromChildren * @attr ref android.R.styleable#ViewGroup_descendantFocusability */ public abstract class ViewGroup extends View implements ViewParent, ViewOpacityManager, ViewManager { private static final boolean DBG = false; /** * Views which have been hidden or removed which need to be animated on * their way out. * This field should be made private, so it is hidden from the SDK. * {@hide} */ protected ArrayListUsing this function takes some care, as it has a fairly complicated * interaction with {@link View#onTouchEvent(MotionEvent) * View.onTouchEvent(MotionEvent)}, and using it requires implementing * that method as well as this one in the correct way. Events will be * received in the following order: * *
* NOTE: In order for this method to be called, you must enable child ordering
* first by calling {@link #setChildrenDrawingOrderEnabled(boolean)}.
*
* @param i The current iteration.
* @return The index of the child to draw this iteration.
*
* @see #setChildrenDrawingOrderEnabled(boolean)
* @see #isChildrenDrawingOrderEnabled()
*/
protected int getChildDrawingOrder(int childCount, int i) {
return i;
}
private void notifyAnimationListener() {
mGroupFlags &= ~FLAG_NOTIFY_ANIMATION_LISTENER;
mGroupFlags |= FLAG_ANIMATION_DONE;
if (mAnimationListener != null) {
final Runnable end = new Runnable() {
public void run() {
mAnimationListener.onAnimationEnd(mLayoutAnimationController.getAnimation());
}
};
post(end);
}
if ((mGroupFlags & FLAG_ANIMATION_CACHE) == FLAG_ANIMATION_CACHE) {
mGroupFlags &= ~FLAG_CHILDREN_DRAWN_WITH_CACHE;
if ((mPersistentDrawingCache & PERSISTENT_ANIMATION_CACHE) == 0) {
setChildrenDrawingCacheEnabled(false);
}
}
invalidate();
}
/**
* Draw one child of this View Group. This method is responsible for getting
* the canvas in the right state. This includes clipping, translating so
* that the child's scrolled origin is at 0, 0, and applying any animation
* transformations.
*
* @param canvas The canvas on which to draw the child
* @param child Who to draw
* @param drawingTime The time at which draw is occuring
* @return True if an invalidate() was issued
*/
protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
boolean more = false;
final int cl = child.mLeft;
final int ct = child.mTop;
final int cr = child.mRight;
final int cb = child.mBottom;
final int flags = mGroupFlags;
if ((flags & FLAG_CLEAR_TRANSFORMATION) == FLAG_CLEAR_TRANSFORMATION) {
if (mChildTransformation != null) {
mChildTransformation.clear();
}
mGroupFlags &= ~FLAG_CLEAR_TRANSFORMATION;
}
Transformation transformToApply = null;
final Animation a = child.getAnimation();
boolean concatMatrix = false;
if (a != null) {
if (mInvalidateRegion == null) {
mInvalidateRegion = new RectF();
}
final RectF region = mInvalidateRegion;
final boolean initialized = a.isInitialized();
if (!initialized) {
a.initialize(cr - cl, cb - ct, getWidth(), getHeight());
a.initializeInvalidateRegion(0, 0, cr - cl, cb - ct);
child.onAnimationStart();
}
if (mChildTransformation == null) {
mChildTransformation = new Transformation();
}
more = a.getTransformation(drawingTime, mChildTransformation);
transformToApply = mChildTransformation;
concatMatrix = a.willChangeTransformationMatrix();
if (more) {
if (!a.willChangeBounds()) {
if ((flags & (FLAG_OPTIMIZE_INVALIDATE | FLAG_ANIMATION_DONE)) ==
FLAG_OPTIMIZE_INVALIDATE) {
mGroupFlags |= FLAG_INVALIDATE_REQUIRED;
} else if ((flags & FLAG_INVALIDATE_REQUIRED) == 0) {
// The child need to draw an animation, potentially offscreen, so
// make sure we do not cancel invalidate requests
mPrivateFlags |= DRAW_ANIMATION;
invalidate(cl, ct, cr, cb);
}
} else {
a.getInvalidateRegion(0, 0, cr - cl, cb - ct, region, transformToApply);
// The child need to draw an animation, potentially offscreen, so
// make sure we do not cancel invalidate requests
mPrivateFlags |= DRAW_ANIMATION;
final int left = cl + (int) region.left;
final int top = ct + (int) region.top;
invalidate(left, top, left + (int) region.width(), top + (int) region.height());
}
}
} else if ((flags & FLAG_SUPPORT_STATIC_TRANSFORMATIONS) ==
FLAG_SUPPORT_STATIC_TRANSFORMATIONS) {
if (mChildTransformation == null) {
mChildTransformation = new Transformation();
}
final boolean hasTransform = getChildStaticTransformation(child, mChildTransformation);
if (hasTransform) {
final int transformType = mChildTransformation.getTransformationType();
transformToApply = transformType != Transformation.TYPE_IDENTITY ?
mChildTransformation : null;
concatMatrix = (transformType & Transformation.TYPE_MATRIX) != 0;
}
}
// Sets the flag as early as possible to allow draw() implementations
// to call invalidate() successfully when doing animations
child.mPrivateFlags |= DRAWN;
if (!concatMatrix && canvas.quickReject(cl, ct, cr, cb, Canvas.EdgeType.BW) &&
(child.mPrivateFlags & DRAW_ANIMATION) == 0) {
return more;
}
child.computeScroll();
final int sx = child.mScrollX;
final int sy = child.mScrollY;
boolean scalingRequired = false;
Bitmap cache = null;
if ((flags & FLAG_CHILDREN_DRAWN_WITH_CACHE) == FLAG_CHILDREN_DRAWN_WITH_CACHE ||
(flags & FLAG_ALWAYS_DRAWN_WITH_CACHE) == FLAG_ALWAYS_DRAWN_WITH_CACHE) {
cache = child.getDrawingCache(true);
if (mAttachInfo != null) scalingRequired = mAttachInfo.mScalingRequired;
}
final boolean hasNoCache = cache == null;
final int restoreTo = canvas.save();
if (hasNoCache) {
canvas.translate(cl - sx, ct - sy);
} else {
canvas.translate(cl, ct);
if (scalingRequired) {
// mAttachInfo cannot be null, otherwise scalingRequired == false
final float scale = 1.0f / mAttachInfo.mApplicationScale;
canvas.scale(scale, scale);
}
}
float alpha = 1.0f;
if (transformToApply != null) {
if (concatMatrix) {
int transX = 0;
int transY = 0;
if (hasNoCache) {
transX = -sx;
transY = -sy;
}
// Undo the scroll translation, apply the transformation matrix,
// then redo the scroll translate to get the correct result.
canvas.translate(-transX, -transY);
canvas.concat(transformToApply.getMatrix());
canvas.translate(transX, transY);
mGroupFlags |= FLAG_CLEAR_TRANSFORMATION;
}
alpha = transformToApply.getAlpha();
if (alpha < 1.0f) {
mGroupFlags |= FLAG_CLEAR_TRANSFORMATION;
}
if (alpha < 1.0f && hasNoCache) {
final int multipliedAlpha = (int) (255 * alpha);
if (!child.onSetAlpha(multipliedAlpha)) {
canvas.saveLayerAlpha(sx, sy, sx + cr - cl, sy + cb - ct, multipliedAlpha,
Canvas.HAS_ALPHA_LAYER_SAVE_FLAG | Canvas.CLIP_TO_LAYER_SAVE_FLAG);
} else {
child.mPrivateFlags |= ALPHA_SET;
}
}
} else if ((child.mPrivateFlags & ALPHA_SET) == ALPHA_SET) {
child.onSetAlpha(255);
}
if ((flags & FLAG_CLIP_CHILDREN) == FLAG_CLIP_CHILDREN) {
if (hasNoCache) {
canvas.clipRect(sx, sy, sx + (cr - cl), sy + (cb - ct));
} else {
if (!scalingRequired) {
canvas.clipRect(0, 0, cr - cl, cb - ct);
} else {
canvas.clipRect(0, 0, cache.getWidth(), cache.getHeight());
}
}
}
if (hasNoCache) {
// Fast path for layouts with no backgrounds
if ((child.mPrivateFlags & SKIP_DRAW) == SKIP_DRAW) {
if (ViewDebug.TRACE_HIERARCHY) {
ViewDebug.trace(this, ViewDebug.HierarchyTraceType.DRAW);
}
child.mPrivateFlags &= ~DIRTY_MASK;
child.dispatchDraw(canvas);
} else {
child.draw(canvas);
}
} else {
final Paint cachePaint = mCachePaint;
if (alpha < 1.0f) {
cachePaint.setAlpha((int) (alpha * 255));
mGroupFlags |= FLAG_ALPHA_LOWER_THAN_ONE;
} else if ((flags & FLAG_ALPHA_LOWER_THAN_ONE) == FLAG_ALPHA_LOWER_THAN_ONE) {
cachePaint.setAlpha(255);
mGroupFlags &= ~FLAG_ALPHA_LOWER_THAN_ONE;
}
if (Config.DEBUG && ViewDebug.profileDrawing) {
EventLog.writeEvent(60003, hashCode());
}
canvas.drawBitmap(cache, 0.0f, 0.0f, cachePaint);
}
canvas.restoreToCount(restoreTo);
if (a != null && !more) {
child.onSetAlpha(255);
finishAnimatingView(child, a);
}
return more;
}
/**
* By default, children are clipped to their bounds before drawing. This
* allows view groups to override this behavior for animations, etc.
*
* @param clipChildren true to clip children to their bounds,
* false otherwise
* @attr ref android.R.styleable#ViewGroup_clipChildren
*/
public void setClipChildren(boolean clipChildren) {
setBooleanFlag(FLAG_CLIP_CHILDREN, clipChildren);
}
/**
* By default, children are clipped to the padding of the ViewGroup. This
* allows view groups to override this behavior
*
* @param clipToPadding true to clip children to the padding of the
* group, false otherwise
* @attr ref android.R.styleable#ViewGroup_clipToPadding
*/
public void setClipToPadding(boolean clipToPadding) {
setBooleanFlag(FLAG_CLIP_TO_PADDING, clipToPadding);
}
/**
* {@inheritDoc}
*/
@Override
public void dispatchSetSelected(boolean selected) {
final View[] children = mChildren;
final int count = mChildrenCount;
for (int i = 0; i < count; i++) {
children[i].setSelected(selected);
}
}
@Override
protected void dispatchSetPressed(boolean pressed) {
final View[] children = mChildren;
final int count = mChildrenCount;
for (int i = 0; i < count; i++) {
children[i].setPressed(pressed);
}
}
/**
* When this property is set to true, this ViewGroup supports static transformations on
* children; this causes
* {@link #getChildStaticTransformation(View, android.view.animation.Transformation)} to be
* invoked when a child is drawn.
*
* Any subclass overriding
* {@link #getChildStaticTransformation(View, android.view.animation.Transformation)} should
* set this property to true.
*
* @param enabled True to enable static transformations on children, false otherwise.
*
* @see #FLAG_SUPPORT_STATIC_TRANSFORMATIONS
*/
protected void setStaticTransformationsEnabled(boolean enabled) {
setBooleanFlag(FLAG_SUPPORT_STATIC_TRANSFORMATIONS, enabled);
}
/**
* {@inheritDoc}
*
* @see #setStaticTransformationsEnabled(boolean)
*/
protected boolean getChildStaticTransformation(View child, Transformation t) {
return false;
}
/**
* {@hide}
*/
@Override
protected View findViewTraversal(int id) {
if (id == mID) {
return this;
}
final View[] where = mChildren;
final int len = mChildrenCount;
for (int i = 0; i < len; i++) {
View v = where[i];
if ((v.mPrivateFlags & IS_ROOT_NAMESPACE) == 0) {
v = v.findViewById(id);
if (v != null) {
return v;
}
}
}
return null;
}
/**
* {@hide}
*/
@Override
protected View findViewWithTagTraversal(Object tag) {
if (tag != null && tag.equals(mTag)) {
return this;
}
final View[] where = mChildren;
final int len = mChildrenCount;
for (int i = 0; i < len; i++) {
View v = where[i];
if ((v.mPrivateFlags & IS_ROOT_NAMESPACE) == 0) {
v = v.findViewWithTag(tag);
if (v != null) {
return v;
}
}
}
return null;
}
/**
* Adds a child view. If no layout parameters are already set on the child, the
* default parameters for this ViewGroup are set on the child.
*
* @param child the child view to add
*
* @see #generateDefaultLayoutParams()
*/
public void addView(View child) {
addView(child, -1);
}
/**
* Adds a child view. If no layout parameters are already set on the child, the
* default parameters for this ViewGroup are set on the child.
*
* @param child the child view to add
* @param index the position at which to add the child
*
* @see #generateDefaultLayoutParams()
*/
public void addView(View child, int index) {
LayoutParams params = child.getLayoutParams();
if (params == null) {
params = generateDefaultLayoutParams();
if (params == null) {
throw new IllegalArgumentException("generateDefaultLayoutParams() cannot return null");
}
}
addView(child, index, params);
}
/**
* Adds a child view with this ViewGroup's default layout parameters and the
* specified width and height.
*
* @param child the child view to add
*/
public void addView(View child, int width, int height) {
final LayoutParams params = generateDefaultLayoutParams();
params.width = width;
params.height = height;
addView(child, -1, params);
}
/**
* Adds a child view with the specified layout parameters.
*
* @param child the child view to add
* @param params the layout parameters to set on the child
*/
public void addView(View child, LayoutParams params) {
addView(child, -1, params);
}
/**
* Adds a child view with the specified layout parameters.
*
* @param child the child view to add
* @param index the position at which to add the child
* @param params the layout parameters to set on the child
*/
public void addView(View child, int index, LayoutParams params) {
if (DBG) {
System.out.println(this + " addView");
}
// addViewInner() will call child.requestLayout() when setting the new LayoutParams
// therefore, we call requestLayout() on ourselves before, so that the child's request
// will be blocked at our level
requestLayout();
invalidate();
addViewInner(child, index, params, false);
}
/**
* {@inheritDoc}
*/
public void updateViewLayout(View view, ViewGroup.LayoutParams params) {
if (!checkLayoutParams(params)) {
throw new IllegalArgumentException("Invalid LayoutParams supplied to " + this);
}
if (view.mParent != this) {
throw new IllegalArgumentException("Given view not a child of " + this);
}
view.setLayoutParams(params);
}
/**
* {@inheritDoc}
*/
protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
return p != null;
}
/**
* Interface definition for a callback to be invoked when the hierarchy
* within this view changed. The hierarchy changes whenever a child is added
* to or removed from this view.
*/
public interface OnHierarchyChangeListener {
/**
* Called when a new child is added to a parent view.
*
* @param parent the view in which a child was added
* @param child the new child view added in the hierarchy
*/
void onChildViewAdded(View parent, View child);
/**
* Called when a child is removed from a parent view.
*
* @param parent the view from which the child was removed
* @param child the child removed from the hierarchy
*/
void onChildViewRemoved(View parent, View child);
}
/**
* Register a callback to be invoked when a child is added to or removed
* from this view.
*
* @param listener the callback to invoke on hierarchy change
*/
public void setOnHierarchyChangeListener(OnHierarchyChangeListener listener) {
mOnHierarchyChangeListener = listener;
}
/**
* Adds a view during layout. This is useful if in your onLayout() method,
* you need to add more views (as does the list view for example).
*
* If index is negative, it means put it at the end of the list.
*
* @param child the view to add to the group
* @param index the index at which the child must be added
* @param params the layout parameters to associate with the child
* @return true if the child was added, false otherwise
*/
protected boolean addViewInLayout(View child, int index, LayoutParams params) {
return addViewInLayout(child, index, params, false);
}
/**
* Adds a view during layout. This is useful if in your onLayout() method,
* you need to add more views (as does the list view for example).
*
* If index is negative, it means put it at the end of the list.
*
* @param child the view to add to the group
* @param index the index at which the child must be added
* @param params the layout parameters to associate with the child
* @param preventRequestLayout if true, calling this method will not trigger a
* layout request on child
* @return true if the child was added, false otherwise
*/
protected boolean addViewInLayout(View child, int index, LayoutParams params,
boolean preventRequestLayout) {
child.mParent = null;
addViewInner(child, index, params, preventRequestLayout);
child.mPrivateFlags = (child.mPrivateFlags & ~DIRTY_MASK) | DRAWN;
return true;
}
/**
* Prevents the specified child to be laid out during the next layout pass.
*
* @param child the child on which to perform the cleanup
*/
protected void cleanupLayoutState(View child) {
child.mPrivateFlags &= ~View.FORCE_LAYOUT;
}
private void addViewInner(View child, int index, LayoutParams params,
boolean preventRequestLayout) {
if (child.getParent() != null) {
throw new IllegalStateException("The specified child already has a parent. " +
"You must call removeView() on the child's parent first.");
}
if (!checkLayoutParams(params)) {
params = generateLayoutParams(params);
}
if (preventRequestLayout) {
child.mLayoutParams = params;
} else {
child.setLayoutParams(params);
}
if (index < 0) {
index = mChildrenCount;
}
addInArray(child, index);
// tell our children
if (preventRequestLayout) {
child.assignParent(this);
} else {
child.mParent = this;
}
if (child.hasFocus()) {
requestChildFocus(child, child.findFocus());
}
AttachInfo ai = mAttachInfo;
if (ai != null) {
boolean lastKeepOn = ai.mKeepScreenOn;
ai.mKeepScreenOn = false;
child.dispatchAttachedToWindow(mAttachInfo, (mViewFlags&VISIBILITY_MASK));
if (ai.mKeepScreenOn) {
needGlobalAttributesUpdate(true);
}
ai.mKeepScreenOn = lastKeepOn;
}
if (mOnHierarchyChangeListener != null) {
mOnHierarchyChangeListener.onChildViewAdded(this, child);
}
if ((child.mViewFlags & DUPLICATE_PARENT_STATE) == DUPLICATE_PARENT_STATE) {
mGroupFlags |= FLAG_NOTIFY_CHILDREN_ON_DRAWABLE_STATE_CHANGE;
}
}
private void addInArray(View child, int index) {
View[] children = mChildren;
final int count = mChildrenCount;
final int size = children.length;
if (index == count) {
if (size == count) {
mChildren = new View[size + ARRAY_CAPACITY_INCREMENT];
System.arraycopy(children, 0, mChildren, 0, size);
children = mChildren;
}
children[mChildrenCount++] = child;
} else if (index < count) {
if (size == count) {
mChildren = new View[size + ARRAY_CAPACITY_INCREMENT];
System.arraycopy(children, 0, mChildren, 0, index);
System.arraycopy(children, index, mChildren, index + 1, count - index);
children = mChildren;
} else {
System.arraycopy(children, index, children, index + 1, count - index);
}
children[index] = child;
mChildrenCount++;
} else {
throw new IndexOutOfBoundsException("index=" + index + " count=" + count);
}
}
// This method also sets the child's mParent to null
private void removeFromArray(int index) {
final View[] children = mChildren;
children[index].mParent = null;
final int count = mChildrenCount;
if (index == count - 1) {
children[--mChildrenCount] = null;
} else if (index >= 0 && index < count) {
System.arraycopy(children, index + 1, children, index, count - index - 1);
children[--mChildrenCount] = null;
} else {
throw new IndexOutOfBoundsException();
}
}
// This method also sets the children's mParent to null
private void removeFromArray(int start, int count) {
final View[] children = mChildren;
final int childrenCount = mChildrenCount;
start = Math.max(0, start);
final int end = Math.min(childrenCount, start + count);
if (start == end) {
return;
}
if (end == childrenCount) {
for (int i = start; i < end; i++) {
children[i].mParent = null;
children[i] = null;
}
} else {
for (int i = start; i < end; i++) {
children[i].mParent = null;
}
// Since we're looping above, we might as well do the copy, but is arraycopy()
// faster than the extra 2 bounds checks we would do in the loop?
System.arraycopy(children, end, children, start, childrenCount - end);
for (int i = childrenCount - (end - start); i < childrenCount; i++) {
children[i] = null;
}
}
mChildrenCount -= (end - start);
}
private void bindLayoutAnimation(View child) {
Animation a = mLayoutAnimationController.getAnimationForView(child);
child.setAnimation(a);
}
/**
* Subclasses should override this method to set layout animation
* parameters on the supplied child.
*
* @param child the child to associate with animation parameters
* @param params the child's layout parameters which hold the animation
* parameters
* @param index the index of the child in the view group
* @param count the number of children in the view group
*/
protected void attachLayoutAnimationParameters(View child,
LayoutParams params, int index, int count) {
LayoutAnimationController.AnimationParameters animationParams =
params.layoutAnimationParameters;
if (animationParams == null) {
animationParams = new LayoutAnimationController.AnimationParameters();
params.layoutAnimationParameters = animationParams;
}
animationParams.count = count;
animationParams.index = index;
}
/**
* {@inheritDoc}
*/
public void removeView(View view) {
removeViewInternal(view);
requestLayout();
invalidate();
}
/**
* Removes a view during layout. This is useful if in your onLayout() method,
* you need to remove more views.
*
* @param view the view to remove from the group
*/
public void removeViewInLayout(View view) {
removeViewInternal(view);
}
/**
* Removes a range of views during layout. This is useful if in your onLayout() method,
* you need to remove more views.
*
* @param start the index of the first view to remove from the group
* @param count the number of views to remove from the group
*/
public void removeViewsInLayout(int start, int count) {
removeViewsInternal(start, count);
}
/**
* Removes the view at the specified position in the group.
*
* @param index the position in the group of the view to remove
*/
public void removeViewAt(int index) {
removeViewInternal(index, getChildAt(index));
requestLayout();
invalidate();
}
/**
* Removes the specified range of views from the group.
*
* @param start the first position in the group of the range of views to remove
* @param count the number of views to remove
*/
public void removeViews(int start, int count) {
removeViewsInternal(start, count);
requestLayout();
invalidate();
}
private void removeViewInternal(View view) {
final int index = indexOfChild(view);
if (index >= 0) {
removeViewInternal(index, view);
}
}
private void removeViewInternal(int index, View view) {
boolean clearChildFocus = false;
if (view == mFocused) {
view.clearFocusForRemoval();
clearChildFocus = true;
}
if (view.getAnimation() != null) {
addDisappearingView(view);
} else if (view.mAttachInfo != null) {
view.dispatchDetachedFromWindow();
}
if (mOnHierarchyChangeListener != null) {
mOnHierarchyChangeListener.onChildViewRemoved(this, view);
}
needGlobalAttributesUpdate(false);
removeFromArray(index);
if (clearChildFocus) {
clearChildFocus(view);
}
}
private void removeViewsInternal(int start, int count) {
final OnHierarchyChangeListener onHierarchyChangeListener = mOnHierarchyChangeListener;
final boolean notifyListener = onHierarchyChangeListener != null;
final View focused = mFocused;
final boolean detach = mAttachInfo != null;
View clearChildFocus = null;
final View[] children = mChildren;
final int end = start + count;
for (int i = start; i < end; i++) {
final View view = children[i];
if (view == focused) {
view.clearFocusForRemoval();
clearChildFocus = view;
}
if (view.getAnimation() != null) {
addDisappearingView(view);
} else if (detach) {
view.dispatchDetachedFromWindow();
}
needGlobalAttributesUpdate(false);
if (notifyListener) {
onHierarchyChangeListener.onChildViewRemoved(this, view);
}
}
removeFromArray(start, count);
if (clearChildFocus != null) {
clearChildFocus(clearChildFocus);
}
}
/**
* Call this method to remove all child views from the
* ViewGroup.
*/
public void removeAllViews() {
removeAllViewsInLayout();
requestLayout();
invalidate();
}
/**
* Called by a ViewGroup subclass to remove child views from itself,
* when it must first know its size on screen before it can calculate how many
* child views it will render. An example is a Gallery or a ListView, which
* may "have" 50 children, but actually only render the number of children
* that can currently fit inside the object on screen. Do not call
* this method unless you are extending ViewGroup and understand the
* view measuring and layout pipeline.
*/
public void removeAllViewsInLayout() {
final int count = mChildrenCount;
if (count <= 0) {
return;
}
final View[] children = mChildren;
mChildrenCount = 0;
final OnHierarchyChangeListener listener = mOnHierarchyChangeListener;
final boolean notify = listener != null;
final View focused = mFocused;
final boolean detach = mAttachInfo != null;
View clearChildFocus = null;
needGlobalAttributesUpdate(false);
for (int i = count - 1; i >= 0; i--) {
final View view = children[i];
if (view == focused) {
view.clearFocusForRemoval();
clearChildFocus = view;
}
if (view.getAnimation() != null) {
addDisappearingView(view);
} else if (detach) {
view.dispatchDetachedFromWindow();
}
if (notify) {
listener.onChildViewRemoved(this, view);
}
view.mParent = null;
children[i] = null;
}
if (clearChildFocus != null) {
clearChildFocus(clearChildFocus);
}
}
/**
* Finishes the removal of a detached view. This method will dispatch the detached from
* window event and notify the hierarchy change listener.
*
* @param child the child to be definitely removed from the view hierarchy
* @param animate if true and the view has an animation, the view is placed in the
* disappearing views list, otherwise, it is detached from the window
*
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #detachAllViewsFromParent()
* @see #detachViewFromParent(View)
* @see #detachViewFromParent(int)
*/
protected void removeDetachedView(View child, boolean animate) {
if (child == mFocused) {
child.clearFocus();
}
if (animate && child.getAnimation() != null) {
addDisappearingView(child);
} else if (child.mAttachInfo != null) {
child.dispatchDetachedFromWindow();
}
if (mOnHierarchyChangeListener != null) {
mOnHierarchyChangeListener.onChildViewRemoved(this, child);
}
}
/**
* Attaches a view to this view group. Attaching a view assigns this group as the parent,
* sets the layout parameters and puts the view in the list of children so it can be retrieved
* by calling {@link #getChildAt(int)}.
*
* This method should be called only for view which were detached from their parent.
*
* @param child the child to attach
* @param index the index at which the child should be attached
* @param params the layout parameters of the child
*
* @see #removeDetachedView(View, boolean)
* @see #detachAllViewsFromParent()
* @see #detachViewFromParent(View)
* @see #detachViewFromParent(int)
*/
protected void attachViewToParent(View child, int index, LayoutParams params) {
child.mLayoutParams = params;
if (index < 0) {
index = mChildrenCount;
}
addInArray(child, index);
child.mParent = this;
child.mPrivateFlags = (child.mPrivateFlags & ~DIRTY_MASK & ~DRAWING_CACHE_VALID) | DRAWN;
if (child.hasFocus()) {
requestChildFocus(child, child.findFocus());
}
}
/**
* Detaches a view from its parent. Detaching a view should be temporary and followed
* either by a call to {@link #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)}
* or a call to {@link #removeDetachedView(View, boolean)}. When a view is detached,
* its parent is null and cannot be retrieved by a call to {@link #getChildAt(int)}.
*
* @param child the child to detach
*
* @see #detachViewFromParent(int)
* @see #detachViewsFromParent(int, int)
* @see #detachAllViewsFromParent()
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #removeDetachedView(View, boolean)
*/
protected void detachViewFromParent(View child) {
removeFromArray(indexOfChild(child));
}
/**
* Detaches a view from its parent. Detaching a view should be temporary and followed
* either by a call to {@link #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)}
* or a call to {@link #removeDetachedView(View, boolean)}. When a view is detached,
* its parent is null and cannot be retrieved by a call to {@link #getChildAt(int)}.
*
* @param index the index of the child to detach
*
* @see #detachViewFromParent(View)
* @see #detachAllViewsFromParent()
* @see #detachViewsFromParent(int, int)
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #removeDetachedView(View, boolean)
*/
protected void detachViewFromParent(int index) {
removeFromArray(index);
}
/**
* Detaches a range of view from their parent. Detaching a view should be temporary and followed
* either by a call to {@link #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)}
* or a call to {@link #removeDetachedView(View, boolean)}. When a view is detached, its
* parent is null and cannot be retrieved by a call to {@link #getChildAt(int)}.
*
* @param start the first index of the childrend range to detach
* @param count the number of children to detach
*
* @see #detachViewFromParent(View)
* @see #detachViewFromParent(int)
* @see #detachAllViewsFromParent()
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #removeDetachedView(View, boolean)
*/
protected void detachViewsFromParent(int start, int count) {
removeFromArray(start, count);
}
/**
* Detaches all views from the parent. Detaching a view should be temporary and followed
* either by a call to {@link #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)}
* or a call to {@link #removeDetachedView(View, boolean)}. When a view is detached,
* its parent is null and cannot be retrieved by a call to {@link #getChildAt(int)}.
*
* @see #detachViewFromParent(View)
* @see #detachViewFromParent(int)
* @see #detachViewsFromParent(int, int)
* @see #attachViewToParent(View, int, android.view.ViewGroup.LayoutParams)
* @see #removeDetachedView(View, boolean)
*/
protected void detachAllViewsFromParent() {
final int count = mChildrenCount;
if (count <= 0) {
return;
}
final View[] children = mChildren;
mChildrenCount = 0;
for (int i = count - 1; i >= 0; i--) {
children[i].mParent = null;
children[i] = null;
}
}
/**
* Don't call or override this method. It is used for the implementation of
* the view hierarchy.
*/
public final void invalidateChild(View child, final Rect dirty) {
if (ViewDebug.TRACE_HIERARCHY) {
ViewDebug.trace(this, ViewDebug.HierarchyTraceType.INVALIDATE_CHILD);
}
ViewParent parent = this;
final AttachInfo attachInfo = mAttachInfo;
if (attachInfo != null) {
final int[] location = attachInfo.mInvalidateChildLocation;
location[CHILD_LEFT_INDEX] = child.mLeft;
location[CHILD_TOP_INDEX] = child.mTop;
// If the child is drawing an animation, we want to copy this flag onto
// ourselves and the parent to make sure the invalidate request goes
// through
final boolean drawAnimation = (child.mPrivateFlags & DRAW_ANIMATION) == DRAW_ANIMATION;
// Check whether the child that requests the invalidate is fully opaque
final boolean isOpaque = child.isOpaque() && !drawAnimation &&
child.getAnimation() != null;
// Mark the child as dirty, using the appropriate flag
// Make sure we do not set both flags at the same time
final int opaqueFlag = isOpaque ? DIRTY_OPAQUE : DIRTY;
do {
View view = null;
if (parent instanceof View) {
view = (View) parent;
}
if (drawAnimation) {
if (view != null) {
view.mPrivateFlags |= DRAW_ANIMATION;
} else if (parent instanceof ViewRoot) {
((ViewRoot) parent).mIsAnimating = true;
}
}
// If the parent is dirty opaque or not dirty, mark it dirty with the opaque
// flag coming from the child that initiated the invalidate
if (view != null && (view.mPrivateFlags & DIRTY_MASK) != DIRTY) {
view.mPrivateFlags = (view.mPrivateFlags & ~DIRTY_MASK) | opaqueFlag;
}
parent = parent.invalidateChildInParent(location, dirty);
} while (parent != null);
}
}
/**
* Don't call or override this method. It is used for the implementation of
* the view hierarchy.
*
* This implementation returns null if this ViewGroup does not have a parent,
* if this ViewGroup is already fully invalidated or if the dirty rectangle
* does not intersect with this ViewGroup's bounds.
*/
public ViewParent invalidateChildInParent(final int[] location, final Rect dirty) {
if (ViewDebug.TRACE_HIERARCHY) {
ViewDebug.trace(this, ViewDebug.HierarchyTraceType.INVALIDATE_CHILD_IN_PARENT);
}
if ((mPrivateFlags & DRAWN) == DRAWN) {
if ((mGroupFlags & (FLAG_OPTIMIZE_INVALIDATE | FLAG_ANIMATION_DONE)) !=
FLAG_OPTIMIZE_INVALIDATE) {
dirty.offset(location[CHILD_LEFT_INDEX] - mScrollX,
location[CHILD_TOP_INDEX] - mScrollY);
final int left = mLeft;
final int top = mTop;
if (dirty.intersect(0, 0, mRight - left, mBottom - top) ||
(mPrivateFlags & DRAW_ANIMATION) == DRAW_ANIMATION) {
mPrivateFlags &= ~DRAWING_CACHE_VALID;
location[CHILD_LEFT_INDEX] = left;
location[CHILD_TOP_INDEX] = top;
return mParent;
}
} else {
mPrivateFlags &= ~DRAWN & ~DRAWING_CACHE_VALID;
location[CHILD_LEFT_INDEX] = mLeft;
location[CHILD_TOP_INDEX] = mTop;
dirty.set(0, 0, mRight - location[CHILD_LEFT_INDEX],
mBottom - location[CHILD_TOP_INDEX]);
return mParent;
}
}
return null;
}
/**
* Offset a rectangle that is in a descendant's coordinate
* space into our coordinate space.
* @param descendant A descendant of this view
* @param rect A rectangle defined in descendant's coordinate space.
*/
public final void offsetDescendantRectToMyCoords(View descendant, Rect rect) {
offsetRectBetweenParentAndChild(descendant, rect, true, false);
}
/**
* Offset a rectangle that is in our coordinate space into an ancestor's
* coordinate space.
* @param descendant A descendant of this view
* @param rect A rectangle defined in descendant's coordinate space.
*/
public final void offsetRectIntoDescendantCoords(View descendant, Rect rect) {
offsetRectBetweenParentAndChild(descendant, rect, false, false);
}
/**
* Helper method that offsets a rect either from parent to descendant or
* descendant to parent.
*/
void offsetRectBetweenParentAndChild(View descendant, Rect rect,
boolean offsetFromChildToParent, boolean clipToBounds) {
// already in the same coord system :)
if (descendant == this) {
return;
}
ViewParent theParent = descendant.mParent;
// search and offset up to the parent
while ((theParent != null)
&& (theParent instanceof View)
&& (theParent != this)) {
if (offsetFromChildToParent) {
rect.offset(descendant.mLeft - descendant.mScrollX,
descendant.mTop - descendant.mScrollY);
if (clipToBounds) {
View p = (View) theParent;
rect.intersect(0, 0, p.mRight - p.mLeft, p.mBottom - p.mTop);
}
} else {
if (clipToBounds) {
View p = (View) theParent;
rect.intersect(0, 0, p.mRight - p.mLeft, p.mBottom - p.mTop);
}
rect.offset(descendant.mScrollX - descendant.mLeft,
descendant.mScrollY - descendant.mTop);
}
descendant = (View) theParent;
theParent = descendant.mParent;
}
// now that we are up to this view, need to offset one more time
// to get into our coordinate space
if (theParent == this) {
if (offsetFromChildToParent) {
rect.offset(descendant.mLeft - descendant.mScrollX,
descendant.mTop - descendant.mScrollY);
} else {
rect.offset(descendant.mScrollX - descendant.mLeft,
descendant.mScrollY - descendant.mTop);
}
} else {
throw new IllegalArgumentException("parameter must be a descendant of this view");
}
}
/**
* Offset the vertical location of all children of this view by the specified number of pixels.
*
* @param offset the number of pixels to offset
*
* @hide
*/
public void offsetChildrenTopAndBottom(int offset) {
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
final View v = children[i];
v.mTop += offset;
v.mBottom += offset;
}
}
/**
* {@inheritDoc}
*/
public boolean getChildVisibleRect(View child, Rect r, android.graphics.Point offset) {
int dx = child.mLeft - mScrollX;
int dy = child.mTop - mScrollY;
if (offset != null) {
offset.x += dx;
offset.y += dy;
}
r.offset(dx, dy);
return r.intersect(0, 0, mRight - mLeft, mBottom - mTop) &&
(mParent == null || mParent.getChildVisibleRect(this, r, offset));
}
/**
* {@inheritDoc}
*/
@Override
protected abstract void onLayout(boolean changed,
int l, int t, int r, int b);
/**
* Indicates whether the view group has the ability to animate its children
* after the first layout.
*
* @return true if the children can be animated, false otherwise
*/
protected boolean canAnimate() {
return mLayoutAnimationController != null;
}
/**
* Runs the layout animation. Calling this method triggers a relayout of
* this view group.
*/
public void startLayoutAnimation() {
if (mLayoutAnimationController != null) {
mGroupFlags |= FLAG_RUN_ANIMATION;
requestLayout();
}
}
/**
* Schedules the layout animation to be played after the next layout pass
* of this view group. This can be used to restart the layout animation
* when the content of the view group changes or when the activity is
* paused and resumed.
*/
public void scheduleLayoutAnimation() {
mGroupFlags |= FLAG_RUN_ANIMATION;
}
/**
* Sets the layout animation controller used to animate the group's
* children after the first layout.
*
* @param controller the animation controller
*/
public void setLayoutAnimation(LayoutAnimationController controller) {
mLayoutAnimationController = controller;
if (mLayoutAnimationController != null) {
mGroupFlags |= FLAG_RUN_ANIMATION;
}
}
/**
* Returns the layout animation controller used to animate the group's
* children.
*
* @return the current animation controller
*/
public LayoutAnimationController getLayoutAnimation() {
return mLayoutAnimationController;
}
/**
* Indicates whether the children's drawing cache is used during a layout
* animation. By default, the drawing cache is enabled but this will prevent
* nested layout animations from working. To nest animations, you must disable
* the cache.
*
* @return true if the animation cache is enabled, false otherwise
*
* @see #setAnimationCacheEnabled(boolean)
* @see View#setDrawingCacheEnabled(boolean)
*/
@ViewDebug.ExportedProperty
public boolean isAnimationCacheEnabled() {
return (mGroupFlags & FLAG_ANIMATION_CACHE) == FLAG_ANIMATION_CACHE;
}
/**
* Enables or disables the children's drawing cache during a layout animation.
* By default, the drawing cache is enabled but this will prevent nested
* layout animations from working. To nest animations, you must disable the
* cache.
*
* @param enabled true to enable the animation cache, false otherwise
*
* @see #isAnimationCacheEnabled()
* @see View#setDrawingCacheEnabled(boolean)
*/
public void setAnimationCacheEnabled(boolean enabled) {
setBooleanFlag(FLAG_ANIMATION_CACHE, enabled);
}
/**
* Indicates whether this ViewGroup will always try to draw its children using their
* drawing cache. By default this property is enabled.
*
* @return true if the animation cache is enabled, false otherwise
*
* @see #setAlwaysDrawnWithCacheEnabled(boolean)
* @see #setChildrenDrawnWithCacheEnabled(boolean)
* @see View#setDrawingCacheEnabled(boolean)
*/
@ViewDebug.ExportedProperty(category = "drawing")
public boolean isAlwaysDrawnWithCacheEnabled() {
return (mGroupFlags & FLAG_ALWAYS_DRAWN_WITH_CACHE) == FLAG_ALWAYS_DRAWN_WITH_CACHE;
}
/**
* Indicates whether this ViewGroup will always try to draw its children using their
* drawing cache. This property can be set to true when the cache rendering is
* slightly different from the children's normal rendering. Renderings can be different,
* for instance, when the cache's quality is set to low.
*
* When this property is disabled, the ViewGroup will use the drawing cache of its
* children only when asked to. It's usually the task of subclasses to tell ViewGroup
* when to start using the drawing cache and when to stop using it.
*
* @param always true to always draw with the drawing cache, false otherwise
*
* @see #isAlwaysDrawnWithCacheEnabled()
* @see #setChildrenDrawnWithCacheEnabled(boolean)
* @see View#setDrawingCacheEnabled(boolean)
* @see View#setDrawingCacheQuality(int)
*/
public void setAlwaysDrawnWithCacheEnabled(boolean always) {
setBooleanFlag(FLAG_ALWAYS_DRAWN_WITH_CACHE, always);
}
/**
* Indicates whether the ViewGroup is currently drawing its children using
* their drawing cache.
*
* @return true if children should be drawn with their cache, false otherwise
*
* @see #setAlwaysDrawnWithCacheEnabled(boolean)
* @see #setChildrenDrawnWithCacheEnabled(boolean)
*/
@ViewDebug.ExportedProperty(category = "drawing")
protected boolean isChildrenDrawnWithCacheEnabled() {
return (mGroupFlags & FLAG_CHILDREN_DRAWN_WITH_CACHE) == FLAG_CHILDREN_DRAWN_WITH_CACHE;
}
/**
* Tells the ViewGroup to draw its children using their drawing cache. This property
* is ignored when {@link #isAlwaysDrawnWithCacheEnabled()} is true. A child's drawing cache
* will be used only if it has been enabled.
*
* Subclasses should call this method to start and stop using the drawing cache when
* they perform performance sensitive operations, like scrolling or animating.
*
* @param enabled true if children should be drawn with their cache, false otherwise
*
* @see #setAlwaysDrawnWithCacheEnabled(boolean)
* @see #isChildrenDrawnWithCacheEnabled()
*/
protected void setChildrenDrawnWithCacheEnabled(boolean enabled) {
setBooleanFlag(FLAG_CHILDREN_DRAWN_WITH_CACHE, enabled);
}
/**
* Indicates whether the ViewGroup is drawing its children in the order defined by
* {@link #getChildDrawingOrder(int, int)}.
*
* @return true if children drawing order is defined by {@link #getChildDrawingOrder(int, int)},
* false otherwise
*
* @see #setChildrenDrawingOrderEnabled(boolean)
* @see #getChildDrawingOrder(int, int)
*/
@ViewDebug.ExportedProperty(category = "drawing")
protected boolean isChildrenDrawingOrderEnabled() {
return (mGroupFlags & FLAG_USE_CHILD_DRAWING_ORDER) == FLAG_USE_CHILD_DRAWING_ORDER;
}
/**
* Tells the ViewGroup whether to draw its children in the order defined by the method
* {@link #getChildDrawingOrder(int, int)}.
*
* @param enabled true if the order of the children when drawing is determined by
* {@link #getChildDrawingOrder(int, int)}, false otherwise
*
* @see #isChildrenDrawingOrderEnabled()
* @see #getChildDrawingOrder(int, int)
*/
protected void setChildrenDrawingOrderEnabled(boolean enabled) {
setBooleanFlag(FLAG_USE_CHILD_DRAWING_ORDER, enabled);
}
private void setBooleanFlag(int flag, boolean value) {
if (value) {
mGroupFlags |= flag;
} else {
mGroupFlags &= ~flag;
}
}
/**
* Returns an integer indicating what types of drawing caches are kept in memory.
*
* @see #setPersistentDrawingCache(int)
* @see #setAnimationCacheEnabled(boolean)
*
* @return one or a combination of {@link #PERSISTENT_NO_CACHE},
* {@link #PERSISTENT_ANIMATION_CACHE}, {@link #PERSISTENT_SCROLLING_CACHE}
* and {@link #PERSISTENT_ALL_CACHES}
*/
@ViewDebug.ExportedProperty(category = "drawing", mapping = {
@ViewDebug.IntToString(from = PERSISTENT_NO_CACHE, to = "NONE"),
@ViewDebug.IntToString(from = PERSISTENT_ALL_CACHES, to = "ANIMATION"),
@ViewDebug.IntToString(from = PERSISTENT_SCROLLING_CACHE, to = "SCROLLING"),
@ViewDebug.IntToString(from = PERSISTENT_ALL_CACHES, to = "ALL")
})
public int getPersistentDrawingCache() {
return mPersistentDrawingCache;
}
/**
* Indicates what types of drawing caches should be kept in memory after
* they have been created.
*
* @see #getPersistentDrawingCache()
* @see #setAnimationCacheEnabled(boolean)
*
* @param drawingCacheToKeep one or a combination of {@link #PERSISTENT_NO_CACHE},
* {@link #PERSISTENT_ANIMATION_CACHE}, {@link #PERSISTENT_SCROLLING_CACHE}
* and {@link #PERSISTENT_ALL_CACHES}
*/
public void setPersistentDrawingCache(int drawingCacheToKeep) {
mPersistentDrawingCache = drawingCacheToKeep & PERSISTENT_ALL_CACHES;
}
/**
* Returns a new set of layout parameters based on the supplied attributes set.
*
* @param attrs the attributes to build the layout parameters from
*
* @return an instance of {@link android.view.ViewGroup.LayoutParams} or one
* of its descendants
*/
public LayoutParams generateLayoutParams(AttributeSet attrs) {
return new LayoutParams(getContext(), attrs);
}
/**
* Returns a safe set of layout parameters based on the supplied layout params.
* When a ViewGroup is passed a View whose layout params do not pass the test of
* {@link #checkLayoutParams(android.view.ViewGroup.LayoutParams)}, this method
* is invoked. This method should return a new set of layout params suitable for
* this ViewGroup, possibly by copying the appropriate attributes from the
* specified set of layout params.
*
* @param p The layout parameters to convert into a suitable set of layout parameters
* for this ViewGroup.
*
* @return an instance of {@link android.view.ViewGroup.LayoutParams} or one
* of its descendants
*/
protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
return p;
}
/**
* Returns a set of default layout parameters. These parameters are requested
* when the View passed to {@link #addView(View)} has no layout parameters
* already set. If null is returned, an exception is thrown from addView.
*
* @return a set of default layout parameters or null
*/
protected LayoutParams generateDefaultLayoutParams() {
return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
}
/**
* @hide
*/
@Override
protected boolean dispatchConsistencyCheck(int consistency) {
boolean result = super.dispatchConsistencyCheck(consistency);
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
if (!children[i].dispatchConsistencyCheck(consistency)) result = false;
}
return result;
}
/**
* @hide
*/
@Override
protected boolean onConsistencyCheck(int consistency) {
boolean result = super.onConsistencyCheck(consistency);
final boolean checkLayout = (consistency & ViewDebug.CONSISTENCY_LAYOUT) != 0;
final boolean checkDrawing = (consistency & ViewDebug.CONSISTENCY_DRAWING) != 0;
if (checkLayout) {
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
if (children[i].getParent() != this) {
result = false;
android.util.Log.d(ViewDebug.CONSISTENCY_LOG_TAG,
"View " + children[i] + " has no parent/a parent that is not " + this);
}
}
}
if (checkDrawing) {
// If this group is dirty, check that the parent is dirty as well
if ((mPrivateFlags & DIRTY_MASK) != 0) {
final ViewParent parent = getParent();
if (parent != null && !(parent instanceof ViewRoot)) {
if ((((View) parent).mPrivateFlags & DIRTY_MASK) == 0) {
result = false;
android.util.Log.d(ViewDebug.CONSISTENCY_LOG_TAG,
"ViewGroup " + this + " is dirty but its parent is not: " + this);
}
}
}
}
return result;
}
/**
* {@inheritDoc}
*/
@Override
protected void debug(int depth) {
super.debug(depth);
String output;
if (mFocused != null) {
output = debugIndent(depth);
output += "mFocused";
Log.d(VIEW_LOG_TAG, output);
}
if (mChildrenCount != 0) {
output = debugIndent(depth);
output += "{";
Log.d(VIEW_LOG_TAG, output);
}
int count = mChildrenCount;
for (int i = 0; i < count; i++) {
View child = mChildren[i];
child.debug(depth + 1);
}
if (mChildrenCount != 0) {
output = debugIndent(depth);
output += "}";
Log.d(VIEW_LOG_TAG, output);
}
}
/**
* Returns the position in the group of the specified child view.
*
* @param child the view for which to get the position
* @return a positive integer representing the position of the view in the
* group, or -1 if the view does not exist in the group
*/
public int indexOfChild(View child) {
final int count = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < count; i++) {
if (children[i] == child) {
return i;
}
}
return -1;
}
/**
* Returns the number of children in the group.
*
* @return a positive integer representing the number of children in
* the group
*/
public int getChildCount() {
return mChildrenCount;
}
/**
* Returns the view at the specified position in the group.
*
* @param index the position at which to get the view from
* @return the view at the specified position or null if the position
* does not exist within the group
*/
public View getChildAt(int index) {
try {
return mChildren[index];
} catch (IndexOutOfBoundsException ex) {
return null;
}
}
/**
* Ask all of the children of this view to measure themselves, taking into
* account both the MeasureSpec requirements for this view and its padding.
* We skip children that are in the GONE state The heavy lifting is done in
* getChildMeasureSpec.
*
* @param widthMeasureSpec The width requirements for this view
* @param heightMeasureSpec The height requirements for this view
*/
protected void measureChildren(int widthMeasureSpec, int heightMeasureSpec) {
final int size = mChildrenCount;
final View[] children = mChildren;
for (int i = 0; i < size; ++i) {
final View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) != GONE) {
measureChild(child, widthMeasureSpec, heightMeasureSpec);
}
}
}
/**
* Ask one of the children of this view to measure itself, taking into
* account both the MeasureSpec requirements for this view and its padding.
* The heavy lifting is done in getChildMeasureSpec.
*
* @param child The child to measure
* @param parentWidthMeasureSpec The width requirements for this view
* @param parentHeightMeasureSpec The height requirements for this view
*/
protected void measureChild(View child, int parentWidthMeasureSpec,
int parentHeightMeasureSpec) {
final LayoutParams lp = child.getLayoutParams();
final int childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec,
mPaddingLeft + mPaddingRight, lp.width);
final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec,
mPaddingTop + mPaddingBottom, lp.height);
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
/**
* Ask one of the children of this view to measure itself, taking into
* account both the MeasureSpec requirements for this view and its padding
* and margins. The child must have MarginLayoutParams The heavy lifting is
* done in getChildMeasureSpec.
*
* @param child The child to measure
* @param parentWidthMeasureSpec The width requirements for this view
* @param widthUsed Extra space that has been used up by the parent
* horizontally (possibly by other children of the parent)
* @param parentHeightMeasureSpec The height requirements for this view
* @param heightUsed Extra space that has been used up by the parent
* vertically (possibly by other children of the parent)
*/
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 = getChildMeasureSpec(parentHeightMeasureSpec,
mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin
+ heightUsed, lp.height);
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
/**
* Does the hard part of measureChildren: figuring out the MeasureSpec to
* pass to a particular child. This method figures out the right MeasureSpec
* for one dimension (height or width) of one child view.
*
* The goal is to combine information from our MeasureSpec with the
* LayoutParams of the child to get the best possible results. For example,
* if the this view knows its size (because its MeasureSpec has a mode of
* EXACTLY), and the child has indicated in its LayoutParams that it wants
* to be the same size as the parent, the parent should ask the child to
* layout given an exact size.
*
* @param spec The requirements for this view
* @param padding The padding of this view for the current dimension and
* margins, if applicable
* @param childDimension How big the child wants to be in the current
* dimension
* @return a MeasureSpec integer for the child
*/
public static int getChildMeasureSpec(int spec, int padding, int childDimension) {
int specMode = MeasureSpec.getMode(spec);
int specSize = MeasureSpec.getSize(spec);
int size = Math.max(0, specSize - padding);
int resultSize = 0;
int resultMode = 0;
switch (specMode) {
// Parent has imposed an exact size on us
case MeasureSpec.EXACTLY:
if (childDimension >= 0) {
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size. So be it.
resultSize = size;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size. It can't be
// bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
}
break;
// Parent has imposed a maximum size on us
case MeasureSpec.AT_MOST:
if (childDimension >= 0) {
// Child wants a specific size... so be it
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size, but our size is not fixed.
// Constrain child to not be bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size. It can't be
// bigger than us.
resultSize = size;
resultMode = MeasureSpec.AT_MOST;
}
break;
// Parent asked to see how big we want to be
case MeasureSpec.UNSPECIFIED:
if (childDimension >= 0) {
// Child wants a specific size... let him have it
resultSize = childDimension;
resultMode = MeasureSpec.EXACTLY;
} else if (childDimension == LayoutParams.MATCH_PARENT) {
// Child wants to be our size... find out how big it should
// be
resultSize = 0;
resultMode = MeasureSpec.UNSPECIFIED;
} else if (childDimension == LayoutParams.WRAP_CONTENT) {
// Child wants to determine its own size.... find out how
// big it should be
resultSize = 0;
resultMode = MeasureSpec.UNSPECIFIED;
}
break;
}
return MeasureSpec.makeMeasureSpec(resultSize, resultMode);
}
/**
* Removes any pending animations for views that have been removed. Call
* this if you don't want animations for exiting views to stack up.
*/
public void clearDisappearingChildren() {
if (mDisappearingChildren != null) {
mDisappearingChildren.clear();
}
}
/**
* Add a view which is removed from mChildren but still needs animation
*
* @param v View to add
*/
private void addDisappearingView(View v) {
ArrayList
* The base LayoutParams class just describes how big the view wants to be
* for both width and height. For each dimension, it can specify one of:
*
*
* There are subclasses of LayoutParams for different subclasses of
* ViewGroup. For example, AbsoluteLayout has its own subclass of
* LayoutParams which adds an X and Y value.
*
* @attr ref android.R.styleable#ViewGroup_Layout_layout_height
* @attr ref android.R.styleable#ViewGroup_Layout_layout_width
*/
public static class LayoutParams {
/**
* Special value for the height or width requested by a View.
* FILL_PARENT means that the view wants to be as big as its parent,
* minus the parent's padding, if any. This value is deprecated
* starting in API Level 8 and replaced by {@link #MATCH_PARENT}.
*/
@SuppressWarnings({"UnusedDeclaration"})
@Deprecated
public static final int FILL_PARENT = -1;
/**
* Special value for the height or width requested by a View.
* MATCH_PARENT means that the view wants to be as big as its parent,
* minus the parent's padding, if any. Introduced in API Level 8.
*/
public static final int MATCH_PARENT = -1;
/**
* Special value for the height or width requested by a View.
* WRAP_CONTENT means that the view wants to be just large enough to fit
* its own internal content, taking its own padding into account.
*/
public static final int WRAP_CONTENT = -2;
/**
* Information about how wide the view wants to be. Can be one of the
* constants FILL_PARENT (replaced by MATCH_PARENT ,
* in API Level 8) or WRAP_CONTENT. or an exact size.
*/
@ViewDebug.ExportedProperty(category = "layout", mapping = {
@ViewDebug.IntToString(from = MATCH_PARENT, to = "MATCH_PARENT"),
@ViewDebug.IntToString(from = WRAP_CONTENT, to = "WRAP_CONTENT")
})
public int width;
/**
* Information about how tall the view wants to be. Can be one of the
* constants FILL_PARENT (replaced by MATCH_PARENT ,
* in API Level 8) or WRAP_CONTENT. or an exact size.
*/
@ViewDebug.ExportedProperty(category = "layout", mapping = {
@ViewDebug.IntToString(from = MATCH_PARENT, to = "MATCH_PARENT"),
@ViewDebug.IntToString(from = WRAP_CONTENT, to = "WRAP_CONTENT")
})
public int height;
/**
* Used to animate layouts.
*/
public LayoutAnimationController.AnimationParameters layoutAnimationParameters;
/**
* Creates a new set of layout parameters. The values are extracted from
* the supplied attributes set and context. The XML attributes mapped
* to this set of layout parameters are:
*
*
*
*
* @param c the application environment
* @param attrs the set of attributes from which to extract the layout
* parameters' values
*/
public LayoutParams(Context c, AttributeSet attrs) {
TypedArray a = c.obtainStyledAttributes(attrs, R.styleable.ViewGroup_Layout);
setBaseAttributes(a,
R.styleable.ViewGroup_Layout_layout_width,
R.styleable.ViewGroup_Layout_layout_height);
a.recycle();
}
/**
* Creates a new set of layout parameters with the specified width
* and height.
*
* @param width the width, either {@link #WRAP_CONTENT},
* {@link #FILL_PARENT} (replaced by {@link #MATCH_PARENT} in
* API Level 8), or a fixed size in pixels
* @param height the height, either {@link #WRAP_CONTENT},
* {@link #FILL_PARENT} (replaced by {@link #MATCH_PARENT} in
* API Level 8), or a fixed size in pixels
*/
public LayoutParams(int width, int height) {
this.width = width;
this.height = height;
}
/**
* Copy constructor. Clones the width and height values of the source.
*
* @param source The layout params to copy from.
*/
public LayoutParams(LayoutParams source) {
this.width = source.width;
this.height = source.height;
}
/**
* Used internally by MarginLayoutParams.
* @hide
*/
LayoutParams() {
}
/**
* Extracts the layout parameters from the supplied attributes.
*
* @param a the style attributes to extract the parameters from
* @param widthAttr the identifier of the width attribute
* @param heightAttr the identifier of the height attribute
*/
protected void setBaseAttributes(TypedArray a, int widthAttr, int heightAttr) {
width = a.getLayoutDimension(widthAttr, "layout_width");
height = a.getLayoutDimension(heightAttr, "layout_height");
}
/**
* Returns a String representation of this set of layout parameters.
*
* @param output the String to prepend to the internal representation
* @return a String with the following format: output +
* "ViewGroup.LayoutParams={ width=WIDTH, height=HEIGHT }"
*
* @hide
*/
public String debug(String output) {
return output + "ViewGroup.LayoutParams={ width="
+ sizeToString(width) + ", height=" + sizeToString(height) + " }";
}
/**
* Converts the specified size to a readable String.
*
* @param size the size to convert
* @return a String instance representing the supplied size
*
* @hide
*/
protected static String sizeToString(int size) {
if (size == WRAP_CONTENT) {
return "wrap-content";
}
if (size == MATCH_PARENT) {
return "match-parent";
}
return String.valueOf(size);
}
}
/**
* Per-child layout information for layouts that support margins.
* See
* {@link android.R.styleable#ViewGroup_MarginLayout ViewGroup Margin Layout Attributes}
* for a list of all child view attributes that this class supports.
*/
public static class MarginLayoutParams extends ViewGroup.LayoutParams {
/**
* The left margin in pixels of the child.
*/
@ViewDebug.ExportedProperty(category = "layout")
public int leftMargin;
/**
* The top margin in pixels of the child.
*/
@ViewDebug.ExportedProperty(category = "layout")
public int topMargin;
/**
* The right margin in pixels of the child.
*/
@ViewDebug.ExportedProperty(category = "layout")
public int rightMargin;
/**
* The bottom margin in pixels of the child.
*/
@ViewDebug.ExportedProperty(category = "layout")
public int bottomMargin;
/**
* Creates a new set of layout parameters. The values are extracted from
* the supplied attributes set and context.
*
* @param c the application environment
* @param attrs the set of attributes from which to extract the layout
* parameters' values
*/
public MarginLayoutParams(Context c, AttributeSet attrs) {
super();
TypedArray a = c.obtainStyledAttributes(attrs, R.styleable.ViewGroup_MarginLayout);
setBaseAttributes(a,
R.styleable.ViewGroup_MarginLayout_layout_width,
R.styleable.ViewGroup_MarginLayout_layout_height);
int margin = a.getDimensionPixelSize(
com.android.internal.R.styleable.ViewGroup_MarginLayout_layout_margin, -1);
if (margin >= 0) {
leftMargin = margin;
topMargin = margin;
rightMargin= margin;
bottomMargin = margin;
} else {
leftMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginLeft, 0);
topMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginTop, 0);
rightMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginRight, 0);
bottomMargin = a.getDimensionPixelSize(
R.styleable.ViewGroup_MarginLayout_layout_marginBottom, 0);
}
a.recycle();
}
/**
* {@inheritDoc}
*/
public MarginLayoutParams(int width, int height) {
super(width, height);
}
/**
* Copy constructor. Clones the width, height and margin values of the source.
*
* @param source The layout params to copy from.
*/
public MarginLayoutParams(MarginLayoutParams source) {
this.width = source.width;
this.height = source.height;
this.leftMargin = source.leftMargin;
this.topMargin = source.topMargin;
this.rightMargin = source.rightMargin;
this.bottomMargin = source.bottomMargin;
}
/**
* {@inheritDoc}
*/
public MarginLayoutParams(LayoutParams source) {
super(source);
}
/**
* Sets the margins, in pixels.
*
* @param left the left margin size
* @param top the top margin size
* @param right the right margin size
* @param bottom the bottom margin size
*
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginLeft
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginTop
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginRight
* @attr ref android.R.styleable#ViewGroup_MarginLayout_layout_marginBottom
*/
public void setMargins(int left, int top, int right, int bottom) {
leftMargin = left;
topMargin = top;
rightMargin = right;
bottomMargin = bottom;
}
}
}
layout_width: the width, either an exact value,
* {@link #WRAP_CONTENT}, or {@link #FILL_PARENT} (replaced by
* {@link #MATCH_PARENT} in API Level 8)layout_height: the height, either an exact value,
* {@link #WRAP_CONTENT}, or {@link #FILL_PARENT} (replaced by
* {@link #MATCH_PARENT} in API Level 8)