/// <summary>Draw one child of this View Group.</summary>
/// <remarks>
/// 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.
/// </remarks>
/// <param name="canvas">The canvas on which to draw the child</param>
/// <param name="child">Who to draw</param>
/// <param name="drawingTime">The time at which draw is occuring</param>
/// <returns>True if an invalidate() was issued</returns>
protected internal virtual bool drawChild(android.graphics.Canvas canvas, android.view.View
child, long drawingTime)
{
bool more = false;
int cl = child.mLeft;
int ct = child.mTop;
int cr = child.mRight;
int cb = child.mBottom;
bool childHasIdentityMatrix = child.hasIdentityMatrix();
int flags = mGroupFlags;
if ((flags & FLAG_CLEAR_TRANSFORMATION) == FLAG_CLEAR_TRANSFORMATION)
{
mChildTransformation.clear();
mGroupFlags &= ~FLAG_CLEAR_TRANSFORMATION;
}
android.view.animation.Transformation transformToApply = null;
android.view.animation.Transformation invalidationTransform;
android.view.animation.Animation a = child.getAnimation();
bool concatMatrix = false;
bool scalingRequired = false;
bool caching;
int layerType = mDrawLayers ? child.getLayerType() : LAYER_TYPE_NONE;
bool hardwareAccelerated = canvas.isHardwareAccelerated();
if ((flags & FLAG_CHILDREN_DRAWN_WITH_CACHE) == FLAG_CHILDREN_DRAWN_WITH_CACHE ||
(flags & FLAG_ALWAYS_DRAWN_WITH_CACHE) == FLAG_ALWAYS_DRAWN_WITH_CACHE)
{
caching = true;
if (mAttachInfo != null)
{
scalingRequired = mAttachInfo.mScalingRequired;
}
}
else
{
caching = (layerType != LAYER_TYPE_NONE) || hardwareAccelerated;
}
if (a != null)
{
bool initialized = a.isInitialized();
if (!initialized)
{
a.initialize(cr - cl, cb - ct, getWidth(), getHeight());
a.initializeInvalidateRegion(0, 0, cr - cl, cb - ct);
child.onAnimationStart();
}
more = a.getTransformation(drawingTime, mChildTransformation, scalingRequired ? mAttachInfo
.mApplicationScale : 1f);
if (scalingRequired && mAttachInfo.mApplicationScale != 1f)
{
if (mInvalidationTransformation == null)
{
mInvalidationTransformation = new android.view.animation.Transformation();
}
invalidationTransform = mInvalidationTransformation;
a.getTransformation(drawingTime, invalidationTransform, 1f);
}
else
{
invalidationTransform = 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
{
if (mInvalidateRegion == null)
{
mInvalidateRegion = new android.graphics.RectF();
}
android.graphics.RectF region = mInvalidateRegion;
a.getInvalidateRegion(0, 0, cr - cl, cb - ct, region, invalidationTransform);
// The child need to draw an animation, potentially offscreen, so
// make sure we do not cancel invalidate requests
mPrivateFlags |= DRAW_ANIMATION;
int left = cl + (int)region.left;
int top = ct + (int)region.top;
invalidate(left, top, left + (int)(region.width() + .5f), top + (int)(region.height
() + .5f));
}
}
}
else
{
if ((flags & FLAG_SUPPORT_STATIC_TRANSFORMATIONS) == FLAG_SUPPORT_STATIC_TRANSFORMATIONS)
{
bool hasTransform = getChildStaticTransformation(child, mChildTransformation);
if (hasTransform)
{
int transformType = mChildTransformation.getTransformationType();
transformToApply = transformType != android.view.animation.Transformation.TYPE_IDENTITY
? mChildTransformation : null;
concatMatrix = (transformType & android.view.animation.Transformation.TYPE_MATRIX
) != 0;
}
}
}
concatMatrix |= !childHasIdentityMatrix;
// 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, android.graphics.Canvas.EdgeType
.BW) && (child.mPrivateFlags & DRAW_ANIMATION) == 0)
{
return more;
}
float alpha = child.getAlpha();
// Bail out early if the view does not need to be drawn
if (alpha <= android.view.ViewConfiguration.ALPHA_THRESHOLD && (child.mPrivateFlags
& ALPHA_SET) == 0 && !(child is android.view.SurfaceView))
{
return more;
}
if (hardwareAccelerated)
{
// Clear INVALIDATED flag to allow invalidation to occur during rendering, but
// retain the flag's value temporarily in the mRecreateDisplayList flag
child.mRecreateDisplayList = (child.mPrivateFlags & INVALIDATED) == INVALIDATED;
child.mPrivateFlags &= ~INVALIDATED;
}
child.computeScroll();
int sx = child.mScrollX;
int sy = child.mScrollY;
android.view.DisplayList displayList = null;
android.graphics.Bitmap cache = null;
bool hasDisplayList = false;
if (caching)
{
if (!hardwareAccelerated)
{
if (layerType != LAYER_TYPE_NONE)
{
layerType = LAYER_TYPE_SOFTWARE;
child.buildDrawingCache(true);
}
cache = child.getDrawingCache(true);
}
else
{
switch (layerType)
{
case LAYER_TYPE_SOFTWARE:
{
child.buildDrawingCache(true);
cache = child.getDrawingCache(true);
break;
}
case LAYER_TYPE_NONE:
{
// Delay getting the display list until animation-driven alpha values are
// set up and possibly passed on to the view
hasDisplayList = child.canHaveDisplayList();
break;
}
}
}
}
bool hasNoCache = cache == null || hasDisplayList;
bool offsetForScroll = cache == null && !hasDisplayList && layerType != LAYER_TYPE_HARDWARE;
int restoreTo = canvas.save();
if (offsetForScroll)
{
canvas.translate(cl - sx, ct - sy);
}
else
{
canvas.translate(cl, ct);
if (scalingRequired)
{
// mAttachInfo cannot be null, otherwise scalingRequired == false
float scale = 1.0f / mAttachInfo.mApplicationScale;
canvas.scale(scale, scale);
}
}
if (transformToApply != null || alpha < 1.0f || !child.hasIdentityMatrix())
{
if (transformToApply != null || !childHasIdentityMatrix)
{
int transX = 0;
int transY = 0;
if (offsetForScroll)
{
transX = -sx;
transY = -sy;
}
if (transformToApply != null)
{
if (concatMatrix)
{
// 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;
}
float transformAlpha = transformToApply.getAlpha();
if (transformAlpha < 1.0f)
{
alpha *= transformToApply.getAlpha();
mGroupFlags |= FLAG_CLEAR_TRANSFORMATION;
}
}
if (!childHasIdentityMatrix)
{
canvas.translate(-transX, -transY);
canvas.concat(child.getMatrix());
canvas.translate(transX, transY);
}
}
if (alpha < 1.0f)
{
mGroupFlags |= FLAG_CLEAR_TRANSFORMATION;
if (hasNoCache)
{
int multipliedAlpha = (int)(255 * alpha);
if (!child.onSetAlpha(multipliedAlpha))
{
int layerFlags = android.graphics.Canvas.HAS_ALPHA_LAYER_SAVE_FLAG;
if ((flags & FLAG_CLIP_CHILDREN) == FLAG_CLIP_CHILDREN || layerType != LAYER_TYPE_NONE)
{
layerFlags |= android.graphics.Canvas.CLIP_TO_LAYER_SAVE_FLAG;
}
if (layerType == LAYER_TYPE_NONE)
{
int scrollX = hasDisplayList ? 0 : sx;
int scrollY = hasDisplayList ? 0 : sy;
canvas.saveLayerAlpha(scrollX, scrollY, scrollX + cr - cl, scrollY + cb - ct, multipliedAlpha
, layerFlags);
}
}
else
{
// Alpha is handled by the child directly, clobber the layer's alpha
child.mPrivateFlags |= ALPHA_SET;
}
}
}
}
else
{
if ((child.mPrivateFlags & ALPHA_SET) == ALPHA_SET)
{
child.onSetAlpha(255);
child.mPrivateFlags &= ~ALPHA_SET;
}
}
if ((flags & FLAG_CLIP_CHILDREN) == FLAG_CLIP_CHILDREN)
{
if (offsetForScroll)
{
canvas.clipRect(sx, sy, sx + (cr - cl), sy + (cb - ct));
}
else
{
if (!scalingRequired || cache == null)
{
canvas.clipRect(0, 0, cr - cl, cb - ct);
}
else
{
canvas.clipRect(0, 0, cache.getWidth(), cache.getHeight());
}
}
}
if (hasDisplayList)
{
displayList = child.getDisplayList();
if (!displayList.isValid())
{
// Uncommon, but possible. If a view is removed from the hierarchy during the call
// to getDisplayList(), the display list will be marked invalid and we should not
// try to use it again.
displayList = null;
hasDisplayList = false;
}
}
if (hasNoCache)
{
bool layerRendered = false;
if (layerType == LAYER_TYPE_HARDWARE)
{
android.view.HardwareLayer layer = child.getHardwareLayer();
if (layer != null && layer.isValid())
{
child.mLayerPaint.setAlpha((int)(alpha * 255));
((android.view.HardwareCanvas)canvas).drawHardwareLayer(layer, 0, 0, child.mLayerPaint
);
layerRendered = true;
}
else
{
int scrollX = hasDisplayList ? 0 : sx;
int scrollY = hasDisplayList ? 0 : sy;
canvas.saveLayer(scrollX, scrollY, scrollX + cr - cl, scrollY + cb - ct, child.mLayerPaint
, android.graphics.Canvas.HAS_ALPHA_LAYER_SAVE_FLAG | android.graphics.Canvas.CLIP_TO_LAYER_SAVE_FLAG
);
}
}
if (!layerRendered)
{
if (!hasDisplayList)
{
// Fast path for layouts with no backgrounds
if ((child.mPrivateFlags & SKIP_DRAW) == SKIP_DRAW)
{
child.mPrivateFlags &= ~DIRTY_MASK;
child.dispatchDraw(canvas);
}
else
{
child.draw(canvas);
}
}
else
{
child.mPrivateFlags &= ~DIRTY_MASK;
((android.view.HardwareCanvas)canvas).drawDisplayList(displayList, cr - cl, cb -
ct, null);
}
}
}
else
{
if (cache != null)
{
child.mPrivateFlags &= ~DIRTY_MASK;
android.graphics.Paint cachePaint;
if (layerType == LAYER_TYPE_NONE)
{
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;
}
}
}
else
{
cachePaint = child.mLayerPaint;
cachePaint.setAlpha((int)(alpha * 255));
}
canvas.drawBitmap(cache, 0.0f, 0.0f, cachePaint);
}
}
canvas.restoreToCount(restoreTo);
if (a != null && !more)
{
if (!hardwareAccelerated && !a.getFillAfter())
{
child.onSetAlpha(255);
}
finishAnimatingView(child, a);
}
if (more && hardwareAccelerated)
{
// invalidation is the trigger to recreate display lists, so if we're using
// display lists to render, force an invalidate to allow the animation to
// continue drawing another frame
invalidate(true);
if (a.hasAlpha() && (child.mPrivateFlags & ALPHA_SET) == ALPHA_SET)
{
// alpha animations should cause the child to recreate its display list
child.invalidate(true);
}
}
child.mRecreateDisplayList = false;
return more;
}
/// <summary>
/// Returns true if a child view contains the specified point when transformed
/// into its coordinate space.
/// </summary>
/// <remarks>
/// Returns true if a child view contains the specified point when transformed
/// into its coordinate space.
/// Child must not be null.
/// </remarks>
/// <hide></hide>
protected internal virtual bool isTransformedTouchPointInView(float x, float y, android.view.View
child, android.graphics.PointF outLocalPoint)
{
float localX = x + mScrollX - child.mLeft;
float localY = y + mScrollY - child.mTop;
if (!child.hasIdentityMatrix() && mAttachInfo != null)
{
float[] localXY = mAttachInfo.mTmpTransformLocation;
localXY[0] = localX;
localXY[1] = localY;
child.getInverseMatrix().mapPoints(localXY);
localX = localXY[0];
localY = localXY[1];
}
bool isInView = child.pointInView(localX, localY);
if (isInView && outLocalPoint != null)
{
outLocalPoint.set(localX, localY);
}
return isInView;
}
/// <summary>
/// Transforms a motion event into the coordinate space of a particular child view,
/// filters out irrelevant pointer ids, and overrides its action if necessary.
/// </summary>
/// <remarks>
/// Transforms a motion event into the coordinate space of a particular child view,
/// filters out irrelevant pointer ids, and overrides its action if necessary.
/// If child is null, assumes the MotionEvent will be sent to this ViewGroup instead.
/// </remarks>
private bool dispatchTransformedTouchEvent(android.view.MotionEvent @event, bool
cancel, android.view.View child, int desiredPointerIdBits)
{
bool handled;
// Canceling motions is a special case. We don't need to perform any transformations
// or filtering. The important part is the action, not the contents.
int oldAction = @event.getAction();
if (cancel || oldAction == android.view.MotionEvent.ACTION_CANCEL)
{
@event.setAction(android.view.MotionEvent.ACTION_CANCEL);
if (child == null)
{
handled = base.dispatchTouchEvent(@event);
}
else
{
handled = child.dispatchTouchEvent(@event);
}
@event.setAction(oldAction);
return handled;
}
// Calculate the number of pointers to deliver.
int oldPointerIdBits = @event.getPointerIdBits();
int newPointerIdBits = oldPointerIdBits & desiredPointerIdBits;
// If for some reason we ended up in an inconsistent state where it looks like we
// might produce a motion event with no pointers in it, then drop the event.
if (newPointerIdBits == 0)
{
return false;
}
// If the number of pointers is the same and we don't need to perform any fancy
// irreversible transformations, then we can reuse the motion event for this
// dispatch as long as we are careful to revert any changes we make.
// Otherwise we need to make a copy.
android.view.MotionEvent transformedEvent;
if (newPointerIdBits == oldPointerIdBits)
{
if (child == null || child.hasIdentityMatrix())
{
if (child == null)
{
handled = base.dispatchTouchEvent(@event);
}
else
{
float offsetX = mScrollX - child.mLeft;
float offsetY = mScrollY - child.mTop;
@event.offsetLocation(offsetX, offsetY);
handled = child.dispatchTouchEvent(@event);
@event.offsetLocation(-offsetX, -offsetY);
}
return handled;
}
transformedEvent = android.view.MotionEvent.obtain(@event);
}
else
{
transformedEvent = @event.split(newPointerIdBits);
}
// Perform any necessary transformations and dispatch.
if (child == null)
{
handled = base.dispatchTouchEvent(transformedEvent);
}
else
{
float offsetX = mScrollX - child.mLeft;
float offsetY = mScrollY - child.mTop;
transformedEvent.offsetLocation(offsetX, offsetY);
if (!child.hasIdentityMatrix())
{
transformedEvent.transform(child.getInverseMatrix());
}
handled = child.dispatchTouchEvent(transformedEvent);
}
// Done.
transformedEvent.recycle();
return handled;
}
/// <summary>
/// Dispatches a generic pointer event to a child, taking into account
/// transformations that apply to the child.
/// </summary>
/// <remarks>
/// Dispatches a generic pointer event to a child, taking into account
/// transformations that apply to the child.
/// </remarks>
/// <param name="event">The event to send.</param>
/// <param name="child">The view to send the event to.</param>
/// <returns>
///
/// <code>true</code>
/// if the child handled the event.
/// </returns>
private bool dispatchTransformedGenericPointerEvent(android.view.MotionEvent @event
, android.view.View child)
{
float offsetX = mScrollX - child.mLeft;
float offsetY = mScrollY - child.mTop;
bool handled;
if (!child.hasIdentityMatrix())
{
android.view.MotionEvent transformedEvent = android.view.MotionEvent.obtain(@event
);
transformedEvent.offsetLocation(offsetX, offsetY);
transformedEvent.transform(child.getInverseMatrix());
handled = child.dispatchGenericMotionEvent(transformedEvent);
transformedEvent.recycle();
}
else
{
@event.offsetLocation(offsetX, offsetY);
handled = child.dispatchGenericMotionEvent(@event);
@event.offsetLocation(-offsetX, -offsetY);
}
return handled;
}
