/* * Copyright (C) 2013 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.view; import android.animation.LayoutTransition; import android.content.Context; import android.graphics.Canvas; import android.graphics.Rect; import android.graphics.drawable.Drawable; import java.util.ArrayList; /** * An overlay is an extra layer that sits on top of a View (the "host view") * which is drawn after all other content in that view (including children, * if the view is a ViewGroup). Interaction with the overlay layer is done * by adding and removing drawables. * * <p>An overlay requested from a ViewGroup is of type {@link ViewGroupOverlay}, * which also supports adding and removing views.</p> * * @see View#getOverlay() View.getOverlay() * @see ViewGroup#getOverlay() ViewGroup.getOverlay() * @see ViewGroupOverlay */ public class ViewOverlay { /** * The actual container for the drawables (and views, if it's a ViewGroupOverlay). * All of the management and rendering details for the overlay are handled in * OverlayViewGroup. */ OverlayViewGroup mOverlayViewGroup; ViewOverlay(Context context, View hostView) { mOverlayViewGroup = new OverlayViewGroup(context, hostView); } /** * Used internally by View and ViewGroup to handle drawing and invalidation * of the overlay * @return */ ViewGroup getOverlayView() { return mOverlayViewGroup; } /** * Adds a Drawable to the overlay. The bounds of the drawable should be relative to * the host view. Any drawable added to the overlay should be removed when it is no longer * needed or no longer visible. * * @param drawable The Drawable to be added to the overlay. This drawable will be * drawn when the view redraws its overlay. * @see #remove(Drawable) */ public void add(Drawable drawable) { mOverlayViewGroup.add(drawable); } /** * Removes the specified Drawable from the overlay. * * @param drawable The Drawable to be removed from the overlay. * @see #add(Drawable) */ public void remove(Drawable drawable) { mOverlayViewGroup.remove(drawable); } /** * Removes all content from the overlay. */ public void clear() { mOverlayViewGroup.clear(); } boolean isEmpty() { return mOverlayViewGroup.isEmpty(); } /** * OverlayViewGroup is a container that View and ViewGroup use to host * drawables and views added to their overlays ({@link ViewOverlay} and * {@link ViewGroupOverlay}, respectively). Drawables are added to the overlay * via the add/remove methods in ViewOverlay, Views are added/removed via * ViewGroupOverlay. These drawable and view objects are * drawn whenever the view itself is drawn; first the view draws its own * content (and children, if it is a ViewGroup), then it draws its overlay * (if it has one). * * <p>Besides managing and drawing the list of drawables, this class serves * two purposes: * (1) it noops layout calls because children are absolutely positioned and * (2) it forwards all invalidation calls to its host view. The invalidation * redirect is necessary because the overlay is not a child of the host view * and invalidation cannot therefore follow the normal path up through the * parent hierarchy.</p> * * @see View#getOverlay() * @see ViewGroup#getOverlay() */ static class OverlayViewGroup extends ViewGroup { /** * The View for which this is an overlay. Invalidations of the overlay are redirected to * this host view. */ View mHostView; /** * The set of drawables to draw when the overlay is rendered. */ ArrayList<Drawable> mDrawables = null; OverlayViewGroup(Context context, View hostView) { super(context); mHostView = hostView; mAttachInfo = mHostView.mAttachInfo; mRight = hostView.getWidth(); mBottom = hostView.getHeight(); // pass right+bottom directly to RenderNode, since not going through setters mRenderNode.setLeftTopRightBottom(0, 0, mRight, mBottom); } public void add(Drawable drawable) { if (mDrawables == null) { mDrawables = new ArrayList<Drawable>(); } if (!mDrawables.contains(drawable)) { // Make each drawable unique in the overlay; can't add it more than once mDrawables.add(drawable); invalidate(drawable.getBounds()); drawable.setCallback(this); } } public void remove(Drawable drawable) { if (mDrawables != null) { mDrawables.remove(drawable); invalidate(drawable.getBounds()); drawable.setCallback(null); } } @Override protected boolean verifyDrawable(Drawable who) { return super.verifyDrawable(who) || (mDrawables != null && mDrawables.contains(who)); } public void add(View child) { if (child.getParent() instanceof ViewGroup) { ViewGroup parent = (ViewGroup) child.getParent(); if (parent != mHostView && parent.getParent() != null && parent.mAttachInfo != null) { // Moving to different container; figure out how to position child such that // it is in the same location on the screen int[] parentLocation = new int[2]; int[] hostViewLocation = new int[2]; parent.getLocationOnScreen(parentLocation); mHostView.getLocationOnScreen(hostViewLocation); child.offsetLeftAndRight(parentLocation[0] - hostViewLocation[0]); child.offsetTopAndBottom(parentLocation[1] - hostViewLocation[1]); } parent.removeView(child); if (parent.getLayoutTransition() != null) { // LayoutTransition will cause the child to delay removal - cancel it parent.getLayoutTransition().cancel(LayoutTransition.DISAPPEARING); } // fail-safe if view is still attached for any reason if (child.getParent() != null) { child.mParent = null; } } super.addView(child); } public void remove(View view) { super.removeView(view); } public void clear() { removeAllViews(); if (mDrawables != null) { mDrawables.clear(); } } boolean isEmpty() { if (getChildCount() == 0 && (mDrawables == null || mDrawables.size() == 0)) { return true; } return false; } @Override public void invalidateDrawable(Drawable drawable) { invalidate(drawable.getBounds()); } @Override protected void dispatchDraw(Canvas canvas) { super.dispatchDraw(canvas); final int numDrawables = (mDrawables == null) ? 0 : mDrawables.size(); for (int i = 0; i < numDrawables; ++i) { mDrawables.get(i).draw(canvas); } } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { // Noop: children are positioned absolutely } /* The following invalidation overrides exist for the purpose of redirecting invalidation to the host view. The overlay is not parented to the host view (since a View cannot be a parent), so the invalidation cannot proceed through the normal parent hierarchy. There is a built-in assumption that the overlay exactly covers the host view, therefore the invalidation rectangles received do not need to be adjusted when forwarded to the host view. */ @Override public void invalidate(Rect dirty) { super.invalidate(dirty); if (mHostView != null) { mHostView.invalidate(dirty); } } @Override public void invalidate(int l, int t, int r, int b) { super.invalidate(l, t, r, b); if (mHostView != null) { mHostView.invalidate(l, t, r, b); } } @Override public void invalidate() { super.invalidate(); if (mHostView != null) { mHostView.invalidate(); } } @Override void invalidate(boolean invalidateCache) { super.invalidate(invalidateCache); if (mHostView != null) { mHostView.invalidate(invalidateCache); } } @Override void invalidateViewProperty(boolean invalidateParent, boolean forceRedraw) { super.invalidateViewProperty(invalidateParent, forceRedraw); if (mHostView != null) { mHostView.invalidateViewProperty(invalidateParent, forceRedraw); } } @Override protected void invalidateParentCaches() { super.invalidateParentCaches(); if (mHostView != null) { mHostView.invalidateParentCaches(); } } @Override protected void invalidateParentIfNeeded() { super.invalidateParentIfNeeded(); if (mHostView != null) { mHostView.invalidateParentIfNeeded(); } } /** * @hide */ @Override public void damageChild(View child, final Rect dirty) { if (mHostView != null) { // Note: This is not a "fast" invalidation. Would be nice to instead invalidate // using DisplayList properties and a dirty rect instead of causing a real // invalidation of the host view int left = child.mLeft; int top = child.mTop; if (!child.getMatrix().isIdentity()) { child.transformRect(dirty); } dirty.offset(left, top); mHostView.invalidate(dirty); } } /** * @hide */ @Override protected ViewParent damageChildInParent(int left, int top, Rect dirty) { if (mHostView instanceof ViewGroup) { return ((ViewGroup) mHostView).damageChildInParent(left, top, dirty); } return null; } @Override public ViewParent invalidateChildInParent(int[] location, Rect dirty) { if (mHostView != null) { dirty.offset(location[0], location[1]); if (mHostView instanceof ViewGroup) { location[0] = 0; location[1] = 0; super.invalidateChildInParent(location, dirty); return ((ViewGroup) mHostView).invalidateChildInParent(location, dirty); } else { invalidate(dirty); } } return null; } } }