| /* |
| * 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 com.example.android.bitmapfun.ui; |
| |
| import android.content.Context; |
| import android.graphics.drawable.Drawable; |
| import android.graphics.drawable.LayerDrawable; |
| import android.util.AttributeSet; |
| import android.widget.ImageView; |
| |
| import com.example.android.bitmapfun.util.RecyclingBitmapDrawable; |
| |
| /** |
| * Sub-class of ImageView which automatically notifies the drawable when it is |
| * being displayed. |
| */ |
| public class RecyclingImageView extends ImageView { |
| |
| public RecyclingImageView(Context context) { |
| super(context); |
| } |
| |
| public RecyclingImageView(Context context, AttributeSet attrs) { |
| super(context, attrs); |
| } |
| |
| /** |
| * @see android.widget.ImageView#onDetachedFromWindow() |
| */ |
| @Override |
| protected void onDetachedFromWindow() { |
| // This has been detached from Window, so clear the drawable |
| setImageDrawable(null); |
| |
| super.onDetachedFromWindow(); |
| } |
| |
| /** |
| * @see android.widget.ImageView#setImageDrawable(android.graphics.drawable.Drawable) |
| */ |
| @Override |
| public void setImageDrawable(Drawable drawable) { |
| // Keep hold of previous Drawable |
| final Drawable previousDrawable = getDrawable(); |
| |
| // Call super to set new Drawable |
| super.setImageDrawable(drawable); |
| |
| // Notify new Drawable that it is being displayed |
| notifyDrawable(drawable, true); |
| |
| // Notify old Drawable so it is no longer being displayed |
| notifyDrawable(previousDrawable, false); |
| } |
| |
| /** |
| * Notifies the drawable that it's displayed state has changed. |
| * |
| * @param drawable |
| * @param isDisplayed |
| */ |
| private static void notifyDrawable(Drawable drawable, final boolean isDisplayed) { |
| if (drawable instanceof RecyclingBitmapDrawable) { |
| // The drawable is a CountingBitmapDrawable, so notify it |
| ((RecyclingBitmapDrawable) drawable).setIsDisplayed(isDisplayed); |
| } else if (drawable instanceof LayerDrawable) { |
| // The drawable is a LayerDrawable, so recurse on each layer |
| LayerDrawable layerDrawable = (LayerDrawable) drawable; |
| for (int i = 0, z = layerDrawable.getNumberOfLayers(); i < z; i++) { |
| notifyDrawable(layerDrawable.getDrawable(i), isDisplayed); |
| } |
| } |
| } |
| |
| } |