Fix for requestLayout-during-layout inefficiencies (cc699b4f) · Commits · e / os / android_frameworks_base

core/java/android/view/View.java

+20 −4

Original line number	Diff line number	Diff line
		@@ -15509,17 +15509,27 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
		* handle possible request-during-layout errors correctly.</p>
		*/
		public void requestLayout() {
		if (mAttachInfo != null && mAttachInfo.mViewRequestingLayout == null) {
		// Only trigger request-during-layout logic if this is the view requesting it,
		// not the views in its parent hierarchy
		ViewRootImpl viewRoot = getViewRootImpl();
		if (viewRoot != null && viewRoot.isInLayout()) {
		viewRoot.requestLayoutDuringLayout(this);
		if (!viewRoot.requestLayoutDuringLayout(this)) {
		return;
		}
		}
		mAttachInfo.mViewRequestingLayout = this;
		}

		mPrivateFlags \|= PFLAG_FORCE_LAYOUT;
		mPrivateFlags \|= PFLAG_INVALIDATED;

		if (mParent != null && !mParent.isLayoutRequested()) {
		mParent.requestLayout();
		}
		if (mAttachInfo != null && mAttachInfo.mViewRequestingLayout == this) {
		mAttachInfo.mViewRequestingLayout = null;
		}
		}

		/**
		@@ -17999,6 +18009,12 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
		*/
		final Point mPoint = new Point();

		/**
		* Used to track which View originated a requestLayout() call, used when
		* requestLayout() is called during layout.
		*/
		View mViewRequestingLayout;

		/**
		* Creates a new set of attachment information with the specified
		* events handler and thread.

core/java/android/view/ViewRootImpl.java

+79 −17

Original line number	Diff line number	Diff line
		@@ -1894,22 +1894,37 @@ public final class ViewRootImpl implements ViewParent,
		}

		/**
		* Called by {@link android.view.View#requestLayout()} if the view hiearchy is currently
		* undergoing a layout pass. requestLayout() should not be called during layout, but if it
		* is called anyway, we handle the situation here rather than leave the hierarchy in an
		* indeterminate state. The solution is to queue up all requests during layout, apply those
		* requests as soon as layout is complete, and then run layout once more immediately. If
		* Called by {@link android.view.View#requestLayout()} if the view hierarchy is currently
		* undergoing a layout pass. requestLayout() should not generally be called during layout,
		* unless the container hierarchy knows what it is doing (i.e., it is fine as long as
		* all children in that container hierarchy are measured and laid out at the end of the layout
		* pass for that container). If requestLayout() is called anyway, we handle it correctly
		* by registering all requesters during a frame as it proceeds. At the end of the frame,
		* we check all of those views to see if any still have pending layout requests, which
		* indicates that they were not correctly handled by their container hierarchy. If that is
		* the case, we clear all such flags in the tree, to remove the buggy flag state that leads
		* to blank containers, and force a second request/measure/layout pass in this frame. If
		* more requestLayout() calls are received during that second layout pass, we post those
		* requests to the next frame, to avoid possible infinite loops.
		* requests to the next frame to avoid possible infinite loops.
		*
		* <p>The return value from this method indicates whether the request should proceed
		* (if it is a request during the first layout pass) or should be skipped and posted to the
		* next frame (if it is a request during the second layout pass).</p>
		*
		* @param view the view that requested the layout.
		*
		* @return true if request should proceed, false otherwise.
		*/
		void requestLayoutDuringLayout(final View view) {
		boolean requestLayoutDuringLayout(final View view) {
		if (view.mParent == null \|\| view.mAttachInfo == null) {
		// Would not normally trigger another layout, so just let it pass through as usual
		return true;
		}
		if (!mHandlingLayoutInLayoutRequest) {
		if (!mLayoutRequesters.contains(view)) {
		Log.w("View", "requestLayout() called by " + view + " during layout pass");
		mLayoutRequesters.add(view);
		}
		return true;
		} else {
		Log.w("View", "requestLayout() called by " + view + " during second layout pass: " +
		"posting to next frame");
		@@ -1919,6 +1934,7 @@ public final class ViewRootImpl implements ViewParent,
		view.requestLayout();
		}
		});
		return false;
		}
		}

		@@ -1937,20 +1953,66 @@ public final class ViewRootImpl implements ViewParent,
		Trace.traceBegin(Trace.TRACE_TAG_VIEW, "layout");
		try {
		host.layout(0, 0, host.getMeasuredWidth(), host.getMeasuredHeight());

		mInLayout = false;
		int numViewsRequestingLayout = mLayoutRequesters.size();
		if (numViewsRequestingLayout > 0) {
		// requestLayout() was called during layout: unusual, but try to handle correctly
		mHandlingLayoutInLayoutRequest = true;
		// requestLayout() was called during layout.
		// If no layout-request flags are set on the requesting views, there is no problem.
		// If some requests are still pending, then we need to clear those flags and do
		// a full request/measure/layout pass to handle this situation.

		// Check state of layout flags for all requesters
		ArrayList<View> mValidLayoutRequesters = null;
		for (int i = 0; i < numViewsRequestingLayout; ++i) {
		mLayoutRequesters.get(i).requestLayout();
		View view = mLayoutRequesters.get(i);
		if ((view.mPrivateFlags & View.PFLAG_FORCE_LAYOUT) == View.PFLAG_FORCE_LAYOUT) {
		while (view != null && view.mAttachInfo != null && view.mParent != null &&
		(view.mPrivateFlags & View.PFLAG_FORCE_LAYOUT) != 0) {
		if ((view.mViewFlags & View.VISIBILITY_MASK) != View.GONE) {
		// Only trigger new requests for non-GONE views
		Log.w(TAG, "requestLayout() improperly called during " +
		"layout: running second layout pass for " + view);
		if (mValidLayoutRequesters == null) {
		mValidLayoutRequesters = new ArrayList<View>();
		}
		mValidLayoutRequesters.add(view);
		break;
		}
		if (view.mParent instanceof View) {
		view = (View) view.mParent;
		} else {
		view = null;
		}
		}
		}
		}
		if (mValidLayoutRequesters != null) {
		// Clear flags throughout hierarchy, walking up from each flagged requester
		for (int i = 0; i < numViewsRequestingLayout; ++i) {
		View view = mLayoutRequesters.get(i);
		while (view != null &&
		(view.mPrivateFlags & View.PFLAG_FORCE_LAYOUT) != 0) {
		view.mPrivateFlags &= ~View.PFLAG_FORCE_LAYOUT;
		if (view.mParent instanceof View) {
		view = (View) view.mParent;
		} else {
		view = null;
		}
		}
		}
		// Process fresh layout requests, then measure and layout
		mHandlingLayoutInLayoutRequest = true;
		int numValidRequests = mValidLayoutRequesters.size();
		for (int i = 0; i < numValidRequests; ++i) {
		mValidLayoutRequesters.get(i).requestLayout();
		}
		measureHierarchy(host, lp, mView.getContext().getResources(),
		desiredWindowWidth, desiredWindowHeight);
		// Now run layout one more time
		mInLayout = true;
		host.layout(0, 0, host.getMeasuredWidth(), host.getMeasuredHeight());
		mHandlingLayoutInLayoutRequest = false;
		}
		mLayoutRequesters.clear();
		}
		} finally {