Refactor FlatViewGroup to use DrawCommandManagers.

Summary: Rework FlatViewGroup to more easily transition into more complex draw command managers.

Reviewed By: ahmedre

Differential Revision: D3536262
This commit is contained in:
Seth Kirby 2016-07-21 23:36:11 -07:00 committed by Ahmed El-Helw
parent a848ce8efd
commit da8ec6fee6
3 changed files with 406 additions and 179 deletions

View File

@ -0,0 +1,213 @@
/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
package com.facebook.react.flat;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.view.View;
import android.view.animation.Animation;
import com.facebook.infer.annotation.Assertions;
import com.facebook.react.views.view.ReactClippingViewGroupHelper;
/**
* Implementation of a {@link DrawCommandManager} with clipping. Performs drawing by iterating
* over an array of DrawCommands, executing them one by one except when the commands are clipped.
*/
/* package */ final class ClippingDrawCommandManager extends DrawCommandManager {
private final FlatViewGroup mFlatViewGroup;
DrawCommand[] mDrawCommands = DrawCommand.EMPTY_ARRAY;
// lookups in o(1) instead of o(log n) - trade space for time
private final Map<Integer, DrawView> mDrawViewMap = new HashMap<>();
// When grandchildren are promoted, these can only be FlatViewGroups, but we need to handle the
// case that we clip subviews and don't promote grandchildren.
private final Map<Integer, View> mClippedSubviews = new HashMap<>();
private final Rect mClippingRect = new Rect();
ClippingDrawCommandManager(FlatViewGroup flatViewGroup, DrawCommand[] drawCommands) {
mFlatViewGroup = flatViewGroup;
initialSetup(drawCommands);
}
private void initialSetup(DrawCommand[] drawCommands) {
mountDrawCommands(drawCommands);
updateClippingRect();
}
@Override
public void mountDrawCommands(DrawCommand[] drawCommands) {
mDrawCommands = drawCommands;
mDrawViewMap.clear();
for (DrawCommand drawCommand : mDrawCommands) {
if (drawCommand instanceof DrawView) {
DrawView drawView = (DrawView) drawCommand;
mDrawViewMap.put(drawView.reactTag, drawView);
}
}
}
private void clip(int id, View view) {
mClippedSubviews.put(id, view);
}
private void unclip(int id) {
mClippedSubviews.remove(id);
}
private boolean isClipped(int id) {
return mClippedSubviews.containsKey(id);
}
@Override
public void mountViews(ViewResolver viewResolver, int[] viewsToAdd, int[] viewsToDetach) {
for (int viewToAdd : viewsToAdd) {
if (viewToAdd > 0) {
View view = viewResolver.getView(viewToAdd);
ensureViewHasNoParent(view);
mFlatViewGroup.addViewInLayout(view);
} else {
View view = viewResolver.getView(-viewToAdd);
ensureViewHasNoParent(view);
DrawView drawView = Assertions.assertNotNull(mDrawViewMap.get(-viewToAdd));
if (!drawView.mPreviouslyDrawn) {
// The DrawView has not been drawn before, which means the bounds changed and triggered
// a new DrawView when it was collected from the shadow node. We have a view with the
// same id temporarily detached, but we no longer know the bounds.
unclip(drawView.reactTag);
mFlatViewGroup.attachViewToParent(view);
} else if (!isClipped(drawView.reactTag)) {
// The DrawView has been drawn before, and is not clipped. Attach it, and it will get
// removed if we update the clipping rect.
mFlatViewGroup.attachViewToParent(view);
}
// The DrawView has been previously drawn and is clipped, so don't attach it.
}
}
for (int viewToDetach : viewsToDetach) {
View view = viewResolver.getView(viewToDetach);
if (view.getParent() != null) {
throw new RuntimeException("Trying to remove view not owned by FlatViewGroup");
} else {
mFlatViewGroup.removeDetachedView(view);
}
// The view isn't clipped anymore, but gone entirely.
unclip(viewToDetach);
}
}
// Returns true if a view is currently animating.
static boolean animating(View view) {
Animation animation = view.getAnimation();
return animation != null && !animation.hasEnded();
}
// Return true if a view is currently onscreen.
boolean withinBounds(View view) {
if (view instanceof FlatViewGroup) {
FlatViewGroup flatChildView = (FlatViewGroup) view;
return mClippingRect.intersects(
flatChildView.getLeft() + flatChildView.mLogicalAdjustments.left,
flatChildView.getTop() + flatChildView.mLogicalAdjustments.top,
flatChildView.getRight() + flatChildView.mLogicalAdjustments.right,
flatChildView.getBottom() + flatChildView.mLogicalAdjustments.bottom);
} else {
return mClippingRect.intersects(
view.getLeft(),
view.getTop(),
view.getRight(),
view.getBottom());
}
}
@Override
public boolean updateClippingRect() {
ReactClippingViewGroupHelper.calculateClippingRect(mFlatViewGroup, mClippingRect);
if (mFlatViewGroup.getParent() == null || mClippingRect.top == mClippingRect.bottom) {
// If we are unparented or are clipping to an empty rect, no op. Return false so we don't
// invalidate.
return false;
}
int index = 0;
boolean needsInvalidate = false;
for (DrawCommand drawCommand : mDrawCommands) {
if (drawCommand instanceof DrawView) {
DrawView drawView = (DrawView) drawCommand;
View view = mClippedSubviews.get(drawView.reactTag);
if (view == null) {
// Not clipped, visible
view = mFlatViewGroup.getChildAt(index++);
if (!animating(view) && !withinBounds(view)) {
// Now off the screen. Don't invalidate in this case, as the canvas should not be
// redrawn unless new elements are coming onscreen.
clip(drawView.reactTag, view);
mFlatViewGroup.detachView(--index);
}
} else {
// Clipped, invisible. We obviously aren't animating here, as if we were then we would not
// have clipped in the first place.
if (withinBounds(view)) {
// Now on the screen. Invalidate as we have a new element to draw.
unclip(drawView.reactTag);
mFlatViewGroup.attachViewToParent(view, index++);
needsInvalidate = true;
}
}
}
}
return needsInvalidate;
}
@Override
public void getClippingRect(Rect outClippingRect) {
outClippingRect.set(mClippingRect);
}
@Override
public Collection<View> getDetachedViews() {
return mClippedSubviews.values();
}
@Override
public void draw(Canvas canvas) {
for (DrawCommand drawCommand : mDrawCommands) {
if (drawCommand instanceof DrawView) {
if (!isClipped(((DrawView) drawCommand).reactTag)) {
drawCommand.draw(mFlatViewGroup, canvas);
}
// else, don't draw, and don't increment index
} else {
drawCommand.draw(mFlatViewGroup, canvas);
}
}
}
@Override
void debugDraw(Canvas canvas) {
for (DrawCommand drawCommand : mDrawCommands) {
if (drawCommand instanceof DrawView) {
if (!isClipped(((DrawView) drawCommand).reactTag)) {
drawCommand.debugDraw(mFlatViewGroup, canvas);
}
// else, don't draw, and don't increment index
} else {
drawCommand.debugDraw(mFlatViewGroup, canvas);
}
}
}
}

View File

@ -0,0 +1,93 @@
/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
package com.facebook.react.flat;
import java.util.Collection;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.view.View;
import android.view.ViewParent;
/**
* Underlying logic behind handling draw commands from {@link FlatViewGroup}.
*/
/* package */ abstract class DrawCommandManager {
/**
* Mount a set of draw commands to this manager. The order the commands are given is the order in
* which they should be drawn. If any of the commands are new DrawViews, then mountViews will be
* called after by the UIManager.
*
* @param drawCommands The draw commands to mount.
*/
abstract void mountDrawCommands(DrawCommand[] drawCommands);
/**
* Add and detach a set of views. The views added here will already have a DrawView passed in
* mountDrawCommands.
*
* @param viewResolver
* @param viewsToAdd The views to add, by tag. If this is a new view, this will be reactTag,
* otherwise it will be -reactTag. This allows to optimize when we have already attached
* views.
* @param viewsToDetach The views to detach, by tag. These will all be positive.
*/
abstract void mountViews(ViewResolver viewResolver, int[] viewsToAdd, int[] viewsToDetach);
/**
* Get the current clipping rect and adjust clipping so that when draw is dispatched we do as
* little work as possible.
*
* @return true if the FlatViewGroup should invalidate.
*/
abstract boolean updateClippingRect();
/**
* Sets an input rect to match the bounds of our current clipping rect.
*
* @param outClippingRect Set the out
*/
abstract void getClippingRect(Rect outClippingRect);
/**
* Return the views that are currently detached, so they can be cleaned up when we are.
*
* @return A collection of the currently detached views.
*/
abstract Collection<View> getDetachedViews();
/**
* Draw the relevant items. This should do as little work as possible.
*
* @param canvas The canvas to draw on.
*/
abstract void draw(Canvas canvas);
/**
* Draws layout bounds for debug.
*
* @param canvas The canvas to draw on.
*/
abstract void debugDraw(Canvas canvas);
/**
* Throw a runtime exception if a view we are trying to attach is already parented.
*
* @param view The view to check.
*/
protected static void ensureViewHasNoParent(View view) {
ViewParent oldParent = view.getParent();
if (oldParent != null) {
throw new RuntimeException(
"Cannot add view " + view + " to DrawCommandManager while it has a parent " + oldParent);
}
}
}

View File

@ -14,8 +14,6 @@ import javax.annotation.Nullable;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import android.annotation.SuppressLint;
import android.content.Context;
@ -28,9 +26,7 @@ import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.animation.Animation;
import com.facebook.infer.annotation.Assertions;
import com.facebook.react.bridge.ReactContext;
import com.facebook.react.bridge.SoftAssertions;
import com.facebook.react.touch.OnInterceptTouchEventListener;
@ -41,11 +37,12 @@ import com.facebook.react.uimanager.ReactPointerEventsView;
import com.facebook.react.uimanager.UIManagerModule;
import com.facebook.react.views.image.ImageLoadEvent;
import com.facebook.react.views.view.ReactClippingViewGroup;
import com.facebook.react.views.view.ReactClippingViewGroupHelper;
/**
* A view that FlatShadowNode hierarchy maps to. Performs drawing by iterating over
* array of DrawCommands, executing them one by one.
* array of DrawCommands, executing them one by one. In the case of clipping, the underlying logic
* is handled by {@link DrawCommandManager}. This lets us separate logic, while also allowing us
* to save on memory for data structures only used in clipping.
*/
/* package */ final class FlatViewGroup extends ViewGroup
implements ReactInterceptingViewGroup, ReactClippingViewGroup,
@ -108,16 +105,12 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
private long mLastTouchDownTime;
private @Nullable OnInterceptTouchEventListener mOnInterceptTouchEventListener;
private boolean mRemoveClippedSubviews;
private @Nullable Rect mClippingRect;
// lookups in o(1) instead of o(log n) - trade space for time
private final Map<Integer, DrawView> mDrawViewMap = new HashMap<>();
// When grandchildren are promoted, these can only be FlatViewGroups, but we need to handle the
// case that we clip subviews and don't promote grandchildren.
private final Map<Integer, View> mClippedSubviews = new HashMap<>();
private static final ArrayList<View> EMPTY_DETACHED_VIEWS = new ArrayList<>(0);
private @Nullable DrawCommandManager mDrawCommandManager;
// for overflow visible, these adjustments are what we can apply to know the actual bounds of
// a ViewGroup while taking overflowing elements into account.
private Rect mLogicalAdjustments = EMPTY_RECT;
/* package */ Rect mLogicalAdjustments = EMPTY_RECT;
/* package */ FlatViewGroup(Context context) {
super(context);
@ -178,34 +171,13 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
mAndroidDebugDraw = true;
}
private void clip(int id, View view) {
mClippedSubviews.put(id, view);
}
private void unclip(int id) {
mClippedSubviews.remove(id);
}
private boolean isClipped(int id) {
return mClippedSubviews.containsKey(id);
}
@Override
public void dispatchDraw(Canvas canvas) {
mAndroidDebugDraw = false;
super.dispatchDraw(canvas);
if (mRemoveClippedSubviews) {
for (DrawCommand drawCommand : mDrawCommands) {
if (drawCommand instanceof DrawView) {
if (!isClipped(((DrawView) drawCommand).reactTag)) {
drawCommand.draw(this, canvas);
}
// else, don't draw, and don't increment index
} else {
drawCommand.draw(this, canvas);
}
}
if (mDrawCommandManager != null) {
mDrawCommandManager.draw(canvas);
} else {
for (DrawCommand drawCommand : mDrawCommands) {
drawCommand.draw(this, canvas);
@ -228,14 +200,17 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
}
}
/**
* Draws layout bounds for debug. Optionally can draw the name of the DrawCommand so you can
* distinguish commands easier.
*
* @param canvas The canvas to draw on.
*/
private void debugDraw(Canvas canvas) {
for (DrawCommand drawCommand : mDrawCommands) {
if (drawCommand instanceof DrawView) {
if (!isClipped(((DrawView) drawCommand).reactTag)) {
drawCommand.debugDraw(this, canvas);
}
// else, don't draw, and don't increment index
if (mDrawCommandManager != null) {
mDrawCommandManager.debugDraw(canvas);
} else {
for (DrawCommand drawCommand : mDrawCommands) {
drawCommand.debugDraw(this, canvas);
}
}
@ -419,10 +394,9 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
super.onAttachedToWindow();
dispatchOnAttached(mAttachDetachListeners);
if (mRemoveClippedSubviews) {
// This is a no op if we aren't clipping, so let updateClippingRect handle the check for us.
updateClippingRect();
}
}
@Override
protected void onDetachedFromWindow() {
@ -447,10 +421,9 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
invalidate();
}
if (mRemoveClippedSubviews) {
// This is a no op if we aren't clipping, so let updateClippingRect handle the check for us.
updateClippingRect();
}
}
@Override
public void dispatchDrawableHotspotChanged(float x, float y) {
@ -600,16 +573,11 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
}
/* package */ void mountDrawCommands(DrawCommand[] drawCommands, Rect logicalAdjustments) {
mDrawCommands = drawCommands;
mLogicalAdjustments = logicalAdjustments;
if (mRemoveClippedSubviews) {
mDrawViewMap.clear();
for (DrawCommand drawCommand : mDrawCommands) {
if (drawCommand instanceof DrawView) {
DrawView drawView = (DrawView) drawCommand;
mDrawViewMap.put(drawView.reactTag, drawView);
}
}
if (mDrawCommandManager != null) {
mDrawCommandManager.mountDrawCommands(drawCommands);
} else {
mDrawCommands = drawCommands;
}
invalidate();
}
@ -633,10 +601,13 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
* strong reference to. This is used by the FlatNativeViewHierarchyManager to explicitly clean up
* those views when removing this parent.
*
* @return a Collection of FlatViewGroups to clean up
* @return a Collection of Views to clean up
*/
Collection<View> getDetachedViews() {
return mClippedSubviews.values();
if (mDrawCommandManager == null) {
return EMPTY_DETACHED_VIEWS;
}
return mDrawCommandManager.getDetachedViews();
}
/**
@ -687,13 +658,13 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
/**
* Mount a list of views to add, and dismount a list of views to detach. Ids will not appear in
* both lists, aka:
* set(viewsToAdd + viewsToDetach).size() == viewsToAdd.length + viewsToDetach.length
* Set(viewsToAdd + viewsToDetach).size() == viewsToAdd.length + viewsToDetach.length
*
* Every time we get any change in the views in a FlatViewGroup, we detach all views first, then
* reattach / remove them as needed. viewsToAdd is odd in that the ids also specify whether
* the view is new to us, or if we were already the parent. If it is new to us, then the id has
* a positive value, otherwise we are already the parent, but it was previously detached, since we
* detach everything when anything changes.
* a positive value, otherwise we are already the parent, but it was previously detached, since
* we detach everything when anything changes.
*
* The reason we detach everything is that a single detach is on the order of O(n), as in the
* average case we have to move half of the views one position to the right, and a single add is
@ -708,30 +679,20 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
* or are being removed entirely.
*/
/* package */ void mountViews(ViewResolver viewResolver, int[] viewsToAdd, int[] viewsToDetach) {
if (mDrawCommandManager != null) {
mDrawCommandManager.mountViews(viewResolver, viewsToAdd, viewsToDetach);
} else {
for (int viewToAdd : viewsToAdd) {
if (viewToAdd > 0) {
View view = ensureViewHasNoParent(viewResolver.getView(viewToAdd));
addViewInLayout(view, -1, ensureLayoutParams(view.getLayoutParams()), true);
View view = viewResolver.getView(viewToAdd);
ensureViewHasNoParent(view);
addViewInLayout(view);
} else {
View view = ensureViewHasNoParent(viewResolver.getView(-viewToAdd));
if (mRemoveClippedSubviews) {
DrawView drawView = Assertions.assertNotNull(mDrawViewMap.get(-viewToAdd));
if (!drawView.mPreviouslyDrawn) {
// The DrawView has not been drawn before, which means the bounds changed and triggered
// a new DrawView when it was collected from the shadow node. We have a view with the
// same id temporarily detached, but we no longer know the bounds.
unclip(drawView.reactTag);
attachViewToParent(view, -1, ensureLayoutParams(view.getLayoutParams()));
} else if (!isClipped(drawView.reactTag)) {
// The DrawView has been drawn before, and is not clipped. Attach it, and it will get
// removed if we update the clipping rect.
attachViewToParent(view, -1, ensureLayoutParams(view.getLayoutParams()));
}
// The DrawView has been previously drawn and is clipped, so don't attach it.
} else {
// We aren't clipping, so attach all the things.
attachViewToParent(view, -1, ensureLayoutParams(view.getLayoutParams()));
}
View view = viewResolver.getView(-viewToAdd);
ensureViewHasNoParent(view);
// We aren't clipping, so attach all the things, clipping is handled by the draw command
// manager, if we have one.
attachViewToParent(view);
}
}
@ -742,15 +703,24 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
} else {
removeDetachedView(view, false);
}
if (mRemoveClippedSubviews) {
unclip(viewToDetach);
}
}
invalidate();
}
/* package */ void addViewInLayout(View view) {
addViewInLayout(view, -1, ensureLayoutParams(view.getLayoutParams()), true);
}
/* package */ void attachViewToParent(View view) {
attachViewToParent(view, -1, ensureLayoutParams(view.getLayoutParams()));
}
/* package */ void attachViewToParent(View view, int index) {
attachViewToParent(view, index, ensureLayoutParams(view.getLayoutParams()));
}
private void processLayoutRequest() {
mIsLayoutRequested = false;
for (int i = 0, childCount = getChildCount(); i != childCount; ++i) {
@ -831,14 +801,12 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
return null;
}
private View ensureViewHasNoParent(View view) {
private static void ensureViewHasNoParent(View view) {
ViewParent oldParent = view.getParent();
if (oldParent != null) {
throw new RuntimeException(
"Cannot add view " + view + " to " + this + " while it has a parent " + oldParent);
"Cannot add view " + view + " to FlatViewGroup while it has a parent " + oldParent);
}
return view;
}
private void dispatchOnAttached(AttachDetachListener[] listeners) {
@ -873,102 +841,55 @@ import com.facebook.react.views.view.ReactClippingViewGroupHelper;
return generateDefaultLayoutParams();
}
// Returns true if a view is currently animating.
static boolean animating(View view) {
Animation animation = view.getAnimation();
return animation != null && !animation.hasEnded();
}
// Return true if a view is currently onscreen.
static boolean withinBounds(View view, Rect clippingRect) {
if (view instanceof FlatViewGroup) {
FlatViewGroup flatChildView = (FlatViewGroup) view;
return clippingRect.intersects(
flatChildView.getLeft() + flatChildView.mLogicalAdjustments.left,
flatChildView.getTop() + flatChildView.mLogicalAdjustments.top,
flatChildView.getRight() + flatChildView.mLogicalAdjustments.right,
flatChildView.getBottom() + flatChildView.mLogicalAdjustments.bottom);
} else {
return clippingRect.intersects(
view.getLeft(),
view.getTop(),
view.getRight(),
view.getBottom());
}
}
@Override
public void updateClippingRect() {
if (!mRemoveClippedSubviews) {
if (mDrawCommandManager == null) {
// Don't update the clipping rect if we aren't clipping.
return;
}
Assertions.assertNotNull(mClippingRect);
ReactClippingViewGroupHelper.calculateClippingRect(this, mClippingRect);
if (getParent() != null && mClippingRect.top != mClippingRect.bottom) {
updateClippingToRect(mClippingRect);
}
}
private void updateClippingToRect(Rect clippingRect) {
int index = 0;
boolean needsInvalidate = false;
for (DrawCommand drawCommand : mDrawCommands) {
if (drawCommand instanceof DrawView) {
DrawView drawView = (DrawView) drawCommand;
View view = mClippedSubviews.get(drawView.reactTag);
if (view == null) {
// Not clipped, visible
view = getChildAt(index++);
if (!animating(view) && !withinBounds(view, clippingRect)) {
// Now off the screen. Don't invalidate in this case, as the canvas should not be
// redrawn unless new elements are coming onscreen.
clip(drawView.reactTag, view);
detachViewFromParent(--index);
}
} else {
// Clipped, invisible. We obviously aren't animating here, as if we were then we would not
// have clipped in the first place.
if (withinBounds(view, clippingRect)) {
// Now on the screen. Invalidate as we have a new element to draw.
unclip(drawView.reactTag);
attachViewToParent(view, index++, ensureLayoutParams(view.getLayoutParams()));
needsInvalidate = true;
}
}
}
}
if (needsInvalidate) {
if (mDrawCommandManager.updateClippingRect()) {
// Manager says something changed.
invalidate();
}
}
/* package */ void detachView(int index) {
detachViewFromParent(index);
}
@Override
public void getClippingRect(Rect outClippingRect) {
outClippingRect.set(mClippingRect);
if (mDrawCommandManager == null) {
// We could call outClippingRect.set(null) here, but throw in case the underlying React Native
// behaviour changes without us knowing.
throw new RuntimeException(
"Trying to get the clipping rect for a non-clipping FlatViewGroup");
}
mDrawCommandManager.getClippingRect(outClippingRect);
}
@Override
public void setRemoveClippedSubviews(boolean removeClippedSubviews) {
if (removeClippedSubviews == mRemoveClippedSubviews) {
boolean currentlyClipping = getRemoveClippedSubviews();
if (removeClippedSubviews == currentlyClipping) {
// We aren't changing state, so don't do anything.
return;
}
mRemoveClippedSubviews = removeClippedSubviews;
if (removeClippedSubviews) {
mClippingRect = new Rect();
updateClippingRect();
} else {
// Add all clipped views back, deallocate additional arrays, remove layoutChangeListener
Assertions.assertNotNull(mClippingRect);
getDrawingRect(mClippingRect);
updateClippingToRect(mClippingRect);
mClippingRect = null;
if (currentlyClipping && !removeClippedSubviews) {
// Trying to go from a clipping to a non-clipping state, not currently supported by Nodes.
// If this is an issue, let us know, but currently there does not seem to be a good case for
// supporting this.
throw new RuntimeException(
"Trying to transition FlatViewGroup from clipping to non-clipping state");
}
mDrawCommandManager = new ClippingDrawCommandManager(this, mDrawCommands);
mDrawCommands = DrawCommand.EMPTY_ARRAY;
// We don't need an invalidate here because this can't cause new views to come onscreen, since
// everything was unclipped.
}
@Override
public boolean getRemoveClippedSubviews() {
return mRemoveClippedSubviews;
return mDrawCommandManager != null;
}
}