List of usage examples for android.view ViewTreeObserver removeOnPreDrawListener
public void removeOnPreDrawListener(OnPreDrawListener victim)
From source file:com.example.android.expandingcells.ExpandingListView.java
/** * This method expands the view that was clicked and animates all the views * around it to make room for the expanding view. There are several steps required * to do this which are outlined below.// w ww.j av a 2 s. co m * * 1. Store the current top and bottom bounds of each visible item in the listview. * 2. Update the layout parameters of the selected view. In the context of this * method, the view should be originally collapsed and set to some custom height. * The layout parameters are updated so as to wrap the content of the additional * text that is to be displayed. * * After invoking a layout to take place, the listview will order all the items * such that there is space for each view. This layout will be independent of what * the bounds of the items were prior to the layout so two pre-draw passes will * be made. This is necessary because after the layout takes place, some views that * were visible before the layout may now be off bounds but a reference to these * views is required so the animation completes as intended. * * 3. The first predraw pass will set the bounds of all the visible items to * their original location before the layout took place and then force another * layout. Since the bounds of the cells cannot be set directly, the method * setSelectionFromTop can be used to achieve a very similar effect. * 4. The expanding view's bounds are animated to what the final values should be * from the original bounds. * 5. The bounds above the expanding view are animated upwards while the bounds * below the expanding view are animated downwards. * 6. The extra text is faded in as its contents become visible throughout the * animation process. * * It is important to note that the listview is disabled during the animation * because the scrolling behaviour is unpredictable if the bounds of the items * within the listview are not constant during the scroll. */ private void expandView(final View view) { final ExpandableListItem viewObject = (ExpandableListItem) getItemAtPosition(getPositionForView(view)); /* Store the original top and bottom bounds of all the cells.*/ final int oldTop = view.getTop(); final int oldBottom = view.getBottom(); final HashMap<View, int[]> oldCoordinates = new HashMap<View, int[]>(); int childCount = getChildCount(); for (int i = 0; i < childCount; i++) { View v = getChildAt(i); ViewCompat.setHasTransientState(v, true); oldCoordinates.put(v, new int[] { v.getTop(), v.getBottom() }); } /* Update the layout so the extra content becomes visible.*/ final View expandingLayout = view.findViewById(R.id.expanding_layout); if (expandingLayout == null) { throw new IllegalStateException("Layout must have a ExpandingLayout called expanding_layout."); } expandingLayout.setVisibility(View.VISIBLE); /* Add an onPreDraw Listener to the listview. onPreDraw will get invoked after onLayout * and onMeasure have run but before anything has been drawn. This * means that the final post layout properties for all the items have already been * determined, but still have not been rendered onto the screen.*/ final ViewTreeObserver observer = getViewTreeObserver(); observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { @Override public boolean onPreDraw() { /* Determine if this is the first or second pass.*/ if (!mShouldRemoveObserver) { mShouldRemoveObserver = true; /* Calculate what the parameters should be for setSelectionFromTop. * The ListView must be offset in a way, such that after the animation * takes place, all the cells that remain visible are rendered completely * by the ListView.*/ int newTop = view.getTop(); int newBottom = view.getBottom(); int newHeight = newBottom - newTop; int oldHeight = oldBottom - oldTop; int delta = newHeight - oldHeight; mTranslate = getExpandingTopAndBottomTranslations(getPositionForView(view), oldTop, oldBottom, delta); int currentTop = view.getTop(); int futureTop = oldTop - mTranslate[0]; int firstChildStartTop = getChildAt(0).getTop(); int firstVisiblePosition = getFirstVisiblePosition(); int deltaTop = currentTop - futureTop; int i; int childCount = getChildCount(); for (i = 0; i < childCount; i++) { View v = getChildAt(i); int height = v.getBottom() - Math.max(0, v.getTop()); if (deltaTop - height > 0) { firstVisiblePosition++; deltaTop -= height; } else { break; } } if (i > 0) { firstChildStartTop = 0; } setSelectionFromTop(firstVisiblePosition, firstChildStartTop - deltaTop); /* Request another layout to update the layout parameters of the cells.*/ requestLayout(); /* Return false such that the ListView does not redraw its contents on * this layout but only updates all the parameters associated with its * children.*/ return false; } /* Remove the predraw listener so this method does not keep getting called. */ mShouldRemoveObserver = false; observer.removeOnPreDrawListener(this); int yTranslateTop = mTranslate[0]; int yTranslateBottom = mTranslate[1]; ArrayList<Animator> animations = new ArrayList<Animator>(); int index = indexOfChild(view); /* Loop through all the views that were on the screen before the cell was * expanded. Some cells will still be children of the ListView while * others will not. The cells that remain children of the ListView * simply have their bounds animated appropriately. The cells that are no * longer children of the ListView also have their bounds animated, but * must also be added to a list of views which will be drawn in dispatchDraw.*/ for (View v : oldCoordinates.keySet()) { int[] old = oldCoordinates.get(v); handleSetTopAndBottom(v, old[0], old[1]); if (v == view) { continue; } else if (v.getParent() == null) { mViewsToDraw.add(v); int delta = old[0] < oldTop ? -yTranslateTop : yTranslateBottom; animations.add(getAnimation(v, old[0], old[1], delta, delta)); } else { int i = indexOfChild(v); if (v != view) { int delta = i > index ? yTranslateBottom : -yTranslateTop; animations.add(getAnimation(v, old[0], old[1], delta, delta)); } ViewCompat.setHasTransientState(v, false); } } /* Adds animation for expanding the cell that was clicked. */ int[] old = oldCoordinates.get(view); animations.add(getAnimation(view, old[0], old[1], -yTranslateTop, yTranslateBottom)); /* Adds an animation for fading in the extra content. */ animations.add(ObjectAnimator.ofFloat(view.findViewById(R.id.expanding_layout), "alpha", 0, 1)); /* Disabled the ListView for the duration of the animation.*/ setEnabled(false); setClickable(false); /* Play all the animations created above together at the same time. */ AnimatorSet s = new AnimatorSet(); s.playTogether(animations); s.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { viewObject.setExpanded(true); setEnabled(true); setClickable(true); if (mViewsToDraw.size() > 0) { for (View v : mViewsToDraw) { ViewCompat.setHasTransientState(v, false); } } mViewsToDraw.clear(); if (mOnExpandingListener != null) { mOnExpandingListener.onExpanded(view); } } }); s.start(); return true; } }); }
From source file:com.example.mike.birdalarm.ExpandingListView.java
/** * This method expands the view that was clicked and animates all the views * around it to make room for the expanding view. There are several steps * required to do this which are outlined below. * <p/>/* w ww .j a v a2 s . co m*/ * 1. Store the current top and bottom bounds of each visible item in the * listview. 2. Update the layout parameters of the selected view. In the * context of this method, the view should be originally collapsed and set * to some custom height. The layout parameters are updated so as to wrap * the content of the additional text that is to be displayed. * <p/> * After invoking a layout to take place, the listview will order all the * items such that there is space for each view. This layout will be * independent of what the bounds of the items were prior to the layout so * two pre-draw passes will be made. This is necessary because after the * layout takes place, some views that were visible before the layout may * now be off bounds but a reference to these views is required so the * animation completes as intended. * <p/> * 3. The first predraw pass will set the bounds of all the visible items to * their original location before the layout took place and then force * another layout. Since the bounds of the cells cannot be set directly, the * method setSelectionFromTop can be used to achieve a very similar effect. * 4. The expanding view's bounds are animated to what the final values * should be from the original bounds. 5. The bounds above the expanding * view are animated upwards while the bounds below the expanding view are * animated downwards. 6. The extra text is faded in as its contents become * visible throughout the animation process. * <p/> * It is important to note that the listview is disabled during the * animation because the scrolling behaviour is unpredictable if the bounds * of the items within the listview are not constant during the scroll. */ public void expandView(final View view) { final Alarm viewObject = (Alarm) getItemAtPosition(getPositionForView(view)); // final CardListItem viewObject = (CardListItem) getItemAtPosition(getPositionForView(view)); /* Store the original top and bottom bounds of all the cells. */ final int oldTop = view.getTop(); final int oldBottom = view.getBottom(); final HashMap<View, int[]> oldCoordinates = new HashMap<>(); int childCount = getChildCount(); for (int i = 0; i < childCount; i++) { View v = getChildAt(i); ViewCompat.setHasTransientState(v, true); oldCoordinates.put(v, new int[] { v.getTop(), v.getBottom() }); } /* Update the layout so the extra content becomes visible. */ final View expandingLayout = view.findViewById(R.id.options_layout); expandingLayout.setVisibility(View.VISIBLE); /* * Add an onPreDraw Listener to the listview. onPreDraw will get invoked * after onLayout and onMeasure have run but before anything has been * drawn. This means that the final post layout properties for all the * items have already been determined, but still have not been rendered * onto the screen. */ final ViewTreeObserver observer = getViewTreeObserver(); observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { @Override public boolean onPreDraw() { /* Determine if this is the first or second pass. */ if (!mShouldRemoveObserver) { mShouldRemoveObserver = true; /* * Calculate what the parameters should be for * setSelectionFromTop. The ListView must be offset in a * way, such that after the animation takes place, all the * cells that remain visible are rendered completely by the * ListView. */ int newTop = view.getTop(); int newBottom = view.getBottom(); int newHeight = newBottom - newTop; int oldHeight = oldBottom - oldTop; int delta = newHeight - oldHeight; mTranslate = getTopAndBottomTranslations(oldTop, oldBottom, delta, true); int currentTop = view.getTop(); int futureTop = oldTop - mTranslate[0]; int firstChildStartTop = getChildAt(0).getTop(); int firstVisiblePosition = getFirstVisiblePosition(); int deltaTop = currentTop - futureTop; int i; int childCount = getChildCount(); for (i = 0; i < childCount; i++) { View v = getChildAt(i); int height = v.getBottom() - Math.max(0, v.getTop()); if (deltaTop - height > 0) { firstVisiblePosition++; deltaTop -= height; } else { break; } } if (i > 0) { firstChildStartTop = 0; } setSelectionFromTop(firstVisiblePosition, firstChildStartTop - deltaTop); /* * Request another layout to update the layout parameters of * the cells. */ requestLayout(); /* * Return false such that the ListView does not redraw its * contents on this layout but only updates all the * parameters associated with its children. */ return false; } /* * Remove the predraw listener so this method does not keep * getting called. */ mShouldRemoveObserver = false; observer.removeOnPreDrawListener(this); int yTranslateTop = mTranslate[0]; int yTranslateBottom = mTranslate[1]; ArrayList<Animator> animations = new ArrayList<>(); int index = indexOfChild(view); /* * Loop through all the views that were on the screen before the * cell was expanded. Some cells will still be children of the * ListView while others will not. The cells that remain * children of the ListView simply have their bounds animated * appropriately. The cells that are no longer children of the * ListView also have their bounds animated, but must also be * added to a list of views which will be drawn in dispatchDraw. */ for (View v : oldCoordinates.keySet()) { int[] old = oldCoordinates.get(v); v.setTop(old[0]); v.setBottom(old[1]); if (v.getParent() == null) { mViewsToDraw.add(v); int delta = old[0] < oldTop ? -yTranslateTop : yTranslateBottom; animations.add(getAnimation(v, delta, delta)); } else { int i = indexOfChild(v); if (v != view) { int delta = i > index ? yTranslateBottom : -yTranslateTop; animations.add(getAnimation(v, delta, delta)); } ViewCompat.setHasTransientState(v, false); } } /* Adds animation for expanding the cell that was clicked. */ animations.add(getAnimation(view, -yTranslateTop, yTranslateBottom)); /* Adds an animation for fading in the extra content. */ animations.add(ObjectAnimator.ofFloat(view.findViewById(R.id.options_layout), View.ALPHA, 0, 1)); /* Disabled the ListView for the duration of the animation. */ setEnabled(false); setClickable(false); /* * Play all the animations created above together at the same * time. */ AnimatorSet s = new AnimatorSet(); s.playTogether(animations); s.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { viewObject.setExpandedState(true); setEnabled(true); setClickable(true); if (mViewsToDraw.size() > 0) { for (View v : mViewsToDraw) { ViewCompat.setHasTransientState(v, false); } } mViewsToDraw.clear(); } }); s.start(); return true; } }); }
From source file:com.jforce.chapelhillnextbus.ExpandingListView.java
/** * This method expands the view that was clicked and animates all the views * around it to make room for the expanding view. There are several steps * required to do this which are outlined below. * <p/>// w w w . j a v a2 s. co m * 1. Store the current top and bottom bounds of each visible item in the * listview. 2. Update the layout parameters of the selected view. In the * context of this method, the view should be originally collapsed and set * to some custom height. The layout parameters are updated so as to wrap * the content of the additional text that is to be displayed. * <p/> * After invoking a layout to take place, the listview will order all the * items such that there is space for each view. This layout will be * independent of what the bounds of the items were prior to the layout so * two pre-draw passes will be made. This is necessary because after the * layout takes place, some views that were visible before the layout may * now be off bounds but a reference to these views is required so the * animation completes as intended. * <p/> * 3. The first predraw pass will set the bounds of all the visible items to * their original location before the layout took place and then force * another layout. Since the bounds of the cells cannot be set directly, the * method setSelectionFromTop can be used to achieve a very similar effect. * 4. The expanding view's bounds are animated to what the final values * should be from the original bounds. 5. The bounds above the expanding * view are animated upwards while the bounds below the expanding view are * animated downwards. 6. The extra text is faded in as its contents become * visible throughout the animation process. * <p/> * It is important to note that the listview is disabled during the * animation because the scrolling behaviour is unpredictable if the bounds * of the items within the listview are not constant during the scroll. */ private void expandView(final View view) { final ExpandableListItem viewObject = (ExpandableListItem) getItemAtPosition(getPositionForView(view)); /* Store the original top and bottom bounds of all the cells. */ final int oldTop = view.getTop(); final int oldBottom = view.getBottom(); final HashMap<View, int[]> oldCoordinates = new HashMap<View, int[]>(); int childCount = getChildCount(); for (int i = 0; i < childCount; i++) { View v = getChildAt(i); ViewCompat.setHasTransientState(v, true); oldCoordinates.put(v, new int[] { v.getTop(), v.getBottom() }); } /* Update the layout so the extra content becomes visible. */ final View expandingLayout = view.findViewById(R.id.expanding_layout); expandingLayout.setVisibility(View.VISIBLE); /* * Add an onPreDraw Listener to the listview. onPreDraw will get invoked * after onLayout and onMeasure have run but before anything has been * drawn. This means that the final post layout properties for all the * items have already been determined, but still have not been rendered * onto the screen. */ final ViewTreeObserver observer = getViewTreeObserver(); observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { @Override public boolean onPreDraw() { /* Determine if this is the first or second pass. */ if (!mShouldRemoveObserver) { mShouldRemoveObserver = true; /* * Calculate what the parameters should be for * setSelectionFromTop. The ListView must be offset in a * way, such that after the animation takes place, all the * cells that remain visible are rendered completely by the * ListView. */ int newTop = view.getTop(); int newBottom = view.getBottom(); int newHeight = newBottom - newTop; int oldHeight = oldBottom - oldTop; int delta = newHeight - oldHeight; mTranslate = getTopAndBottomTranslations(oldTop, oldBottom, delta, true); int currentTop = view.getTop(); int futureTop = oldTop - mTranslate[0]; int firstChildStartTop = getChildAt(0).getTop(); int firstVisiblePosition = getFirstVisiblePosition(); int deltaTop = currentTop - futureTop; int i; int childCount = getChildCount(); for (i = 0; i < childCount; i++) { View v = getChildAt(i); int height = v.getBottom() - Math.max(0, v.getTop()); if (deltaTop - height > 0) { firstVisiblePosition++; deltaTop -= height; } else { break; } } if (i > 0) { firstChildStartTop = 0; } setSelectionFromTop(firstVisiblePosition, firstChildStartTop - deltaTop); /* * Request another layout to update the layout parameters of * the cells. */ requestLayout(); /* * Return false such that the ListView does not redraw its * contents on this layout but only updates all the * parameters associated with its children. */ return false; } /* * Remove the predraw listener so this method does not keep * getting called. */ mShouldRemoveObserver = false; observer.removeOnPreDrawListener(this); int yTranslateTop = mTranslate[0]; int yTranslateBottom = mTranslate[1]; ArrayList<Animator> animations = new ArrayList<Animator>(); int index = indexOfChild(view); /* * Loop through all the views that were on the screen before the * cell was expanded. Some cells will still be children of the * ListView while others will not. The cells that remain * children of the ListView simply have their bounds animated * appropriately. The cells that are no longer children of the * ListView also have their bounds animated, but must also be * added to a list of views which will be drawn in dispatchDraw. */ for (View v : oldCoordinates.keySet()) { int[] old = oldCoordinates.get(v); v.setTop(old[0]); v.setBottom(old[1]); if (v.getParent() == null) { mViewsToDraw.add(v); int delta = old[0] < oldTop ? -yTranslateTop : yTranslateBottom; animations.add(getAnimation(v, delta, delta)); } else { int i = indexOfChild(v); if (v != view) { int delta = i > index ? yTranslateBottom : -yTranslateTop; animations.add(getAnimation(v, delta, delta)); } ViewCompat.setHasTransientState(v, false); } } /* Adds animation for expanding the cell that was clicked. */ animations.add(getAnimation(view, -yTranslateTop, yTranslateBottom)); /* Adds an animation for fading in the extra content. */ animations.add(ObjectAnimator.ofFloat(view.findViewById(R.id.expanding_layout), View.ALPHA, 0, 1)); /* Disabled the ListView for the duration of the animation. */ setEnabled(false); setClickable(false); /* * Play all the animations created above together at the same * time. */ AnimatorSet s = new AnimatorSet(); s.playTogether(animations); s.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { viewObject.setExpanded(true); setEnabled(true); setClickable(true); if (mViewsToDraw.size() > 0) { for (View v : mViewsToDraw) { ViewCompat.setHasTransientState(v, false); } } mViewsToDraw.clear(); } }); s.start(); return true; } }); }
From source file:graphic.expand_graphic.ExpandingListView.java
/** * This method expands the view that was clicked and animates all the views * around it to make room for the expanding view. There are several steps * required to do this which are outlined below. * <p/>//w w w . j av a2 s . c o m * 1. Store the current top and bottom bounds of each visible item in the * listview. 2. Update the layout parameters of the selected view. In the * context of this method, the view should be originally collapsed and set * to some custom height. The layout parameters are updated so as to wrap * the content of the additional text that is to be displayed. * <p/> * After invoking a layout to take place, the listview will order all the * items such that there is space for each view. This layout will be * independent of what the bounds of the items were prior to the layout so * two pre-draw passes will be made. This is necessary because after the * layout takes place, some views that were visible before the layout may * now be off bounds but a reference to these views is required so the * animation completes as intended. * <p/> * 3. The first predraw pass will set the bounds of all the visible items to * their original location before the layout took place and then force * another layout. Since the bounds of the cells cannot be set directly, the * method setSelectionFromTop can be used to achieve a very similar effect. * 4. The expanding view's bounds are animated to what the final values * should be from the original bounds. 5. The bounds above the expanding * view are animated upwards while the bounds below the expanding view are * animated downwards. 6. The extra text is faded in as its contents become * visible throughout the animation process. * <p/> * It is important to note that the listview is disabled during the * animation because the scrolling behaviour is unpredictable if the bounds * of the items within the listview are not constant during the scroll. */ private void expandView(final View view) { /* Store the original top and bottom bounds of all the cells. */ final int oldTop = view.getTop(); final int oldBottom = view.getBottom(); final HashMap<View, int[]> oldCoordinates = new HashMap<View, int[]>(); int childCount = getChildCount(); for (int i = 0; i < childCount; i++) { View v = getChildAt(i); ViewCompat.setHasTransientState(v, true); oldCoordinates.put(v, new int[] { v.getTop(), v.getBottom() }); } /* Update the layout so the extra content becomes visible. */ final View expandingLayout = view.findViewById(R.id.expanding_layout); expandingLayout.setVisibility(View.VISIBLE); /* * Add an onPreDraw Listener to the listview. onPreDraw will get invoked * after onLayout and onMeasure have run but before anything has been * drawn. This means that the final post layout properties for all the * items have already been determined, but still have not been rendered * onto the screen. */ final ViewTreeObserver observer = getViewTreeObserver(); observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { @Override public boolean onPreDraw() { /* Determine if this is the first or second pass. */ if (!mShouldRemoveObserver) { mShouldRemoveObserver = true; /* * Calculate what the parameters should be for * setSelectionFromTop. The ListView must be offset in a * way, such that after the animation takes place, all the * cells that remain visible are rendered completely by the * ListView. */ int newTop = view.getTop(); int newBottom = view.getBottom(); int newHeight = newBottom - newTop; int oldHeight = oldBottom - oldTop; int delta = newHeight - oldHeight; mTranslate = getTopAndBottomTranslations(oldTop, oldBottom, delta, true); int currentTop = view.getTop(); int futureTop = oldTop - mTranslate[0]; int firstChildStartTop = getChildAt(0).getTop(); int firstVisiblePosition = getFirstVisiblePosition(); int deltaTop = currentTop - futureTop; int i; int childCount = getChildCount(); for (i = 0; i < childCount; i++) { View v = getChildAt(i); int height = v.getBottom() - Math.max(0, v.getTop()); if (deltaTop - height > 0) { firstVisiblePosition++; deltaTop -= height; } else { break; } } if (i > 0) { firstChildStartTop = 0; } setSelectionFromTop(firstVisiblePosition, firstChildStartTop - deltaTop); /* * Request another layout to update the layout parameters of * the cells. */ requestLayout(); /* * Return false such that the ListView does not redraw its * contents on this layout but only updates all the * parameters associated with its children. */ return false; } /* * Remove the predraw listener so this method does not keep * getting called. */ mShouldRemoveObserver = false; observer.removeOnPreDrawListener(this); int yTranslateTop = mTranslate[0]; int yTranslateBottom = mTranslate[1]; ArrayList<Animator> animations = new ArrayList<Animator>(); int index = indexOfChild(view); /* * Loop through all the views that were on the screen before the * cell was expanded. Some cells will still be children of the * ListView while others will not. The cells that remain * children of the ListView simply have their bounds animated * appropriately. The cells that are no longer children of the * ListView also have their bounds animated, but must also be * added to a list of views which will be drawn in dispatchDraw. */ for (View v : oldCoordinates.keySet()) { int[] old = oldCoordinates.get(v); v.setTop(old[0]); v.setBottom(old[1]); if (v.getParent() == null) { mViewsToDraw.add(v); int delta = old[0] < oldTop ? -yTranslateTop : yTranslateBottom; animations.add(getAnimation(v, delta, delta)); } else { int i = indexOfChild(v); if (v != view) { int delta = i > index ? yTranslateBottom : -yTranslateTop; animations.add(getAnimation(v, delta, delta)); } ViewCompat.setHasTransientState(v, false); } } /* Adds animation for expanding the cell that was clicked. */ animations.add(getAnimation(view, -yTranslateTop, yTranslateBottom)); /* Adds an animation for fading in the extra content. */ animations.add(ObjectAnimator.ofFloat(view.findViewById(R.id.expanding_layout), View.ALPHA, 0, 1)); /* Disabled the ListView for the duration of the animation. */ setEnabled(false); setClickable(false); /* * Play all the animations created above together at the same * time. */ AnimatorSet s = new AnimatorSet(); s.playTogether(animations); s.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { viewObject.setExpanded(true); setEnabled(true); setClickable(true); if (mViewsToDraw.size() > 0) { for (View v : mViewsToDraw) { ViewCompat.setHasTransientState(v, false); } } mViewsToDraw.clear(); } }); s.start(); return true; } }); }
From source file:com.android.launcher2.Launcher.java
public void onWindowVisibilityChanged(int visibility) { mVisible = visibility == View.VISIBLE; updateRunning();//www.j av a2 s .com // The following code used to be in onResume, but it turns out onResume is called when // you're in All Apps and click home to go to the workspace. onWindowVisibilityChanged // is a more appropriate event to handle if (mVisible) { mAppsCustomizeTabHost.onWindowVisible(); if (!mWorkspaceLoading) { final ViewTreeObserver observer = mWorkspace.getViewTreeObserver(); // We want to let Launcher draw itself at least once before we force it to build // layers on all the workspace pages, so that transitioning to Launcher from other // apps is nice and speedy. Usually the first call to preDraw doesn't correspond to // a true draw so we wait until the second preDraw call to be safe observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { public boolean onPreDraw() { // We delay the layer building a bit in order to give // other message processing a time to run. In particular // this avoids a delay in hiding the IME if it was // currently shown, because doing that may involve // some communication back with the app. mWorkspace.postDelayed(mBuildLayersRunnable, 500); observer.removeOnPreDrawListener(this); return true; } }); } // When Launcher comes back to foreground, a different Activity might be responsible for // the app market intent, so refresh the icon updateAppMarketIcon(); clearTypedText(); } }