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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.example.android.displayingbitmaps.util;
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import android.content.res.Resources;
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import android.graphics.Bitmap;
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import android.graphics.drawable.BitmapDrawable;
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import com.example.android.common.logger.Log;
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import com.example.android.displayingbitmaps.BuildConfig;
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/**
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* A BitmapDrawable that keeps track of whether it is being displayed or cached.
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* When the drawable is no longer being displayed or cached,
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* {@link android.graphics.Bitmap#recycle() recycle()} will be called on this drawable's bitmap.
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*/
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public class RecyclingBitmapDrawable extends BitmapDrawable {
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static final String TAG = "CountingBitmapDrawable";
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private int mCacheRefCount = 0;
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private int mDisplayRefCount = 0;
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private boolean mHasBeenDisplayed;
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public RecyclingBitmapDrawable(Resources res, Bitmap bitmap) {
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super(res, bitmap);
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}
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/**
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* Notify the drawable that the displayed state has changed. Internally a
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* count is kept so that the drawable knows when it is no longer being
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* displayed.
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*
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* @param isDisplayed - Whether the drawable is being displayed or not
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*/
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public void setIsDisplayed(boolean isDisplayed) {
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synchronized (this) {
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if (isDisplayed) {
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mDisplayRefCount++;
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mHasBeenDisplayed = true;
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} else {
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mDisplayRefCount--;
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}
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}
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// Check to see if recycle() can be called
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checkState();
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}
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/**
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* Notify the drawable that the cache state has changed. Internally a count
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* is kept so that the drawable knows when it is no longer being cached.
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*
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* @param isCached - Whether the drawable is being cached or not
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*/
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public void setIsCached(boolean isCached) {
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synchronized (this) {
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if (isCached) {
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mCacheRefCount++;
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} else {
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mCacheRefCount--;
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}
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}
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// Check to see if recycle() can be called
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checkState();
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}
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private synchronized void checkState() {
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// If the drawable cache and display ref counts = 0, and this drawable
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// has been displayed, then recycle
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if (mCacheRefCount <= 0 && mDisplayRefCount <= 0 && mHasBeenDisplayed
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&& hasValidBitmap()) {
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if (BuildConfig.DEBUG) {
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Log.d(TAG, "No longer being used or cached so recycling. "
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+ toString());
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}
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getBitmap().recycle();
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}
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}
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private synchronized boolean hasValidBitmap() {
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Bitmap bitmap = getBitmap();
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return bitmap != null && !bitmap.isRecycled();
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}
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}