Java tutorial
/* * Copyright (C) 2012 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.ifeng.util.imagecache; import java.io.File; import java.lang.ref.WeakReference; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.util.concurrent.Executor; import java.util.concurrent.Executors; import android.content.Context; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Rect; import android.graphics.drawable.BitmapDrawable; import android.graphics.drawable.ColorDrawable; import android.graphics.drawable.Drawable; import android.graphics.drawable.NinePatchDrawable; import android.graphics.drawable.TransitionDrawable; import android.net.Uri; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentManager; import android.text.TextUtils; import android.widget.ImageView; import com.ifeng.BaseApplicaion; import com.ifeng.android.BuildConfig; import com.ifeng.util.logging.Log; /** * This class wraps up completing some arbitrary long running work when loading * a bitmap to an ImageView. It handles things like using a memory and disk * cache, running the work in a background thread and setting a placeholder * image. */ public abstract class ImageWorker { private static final String TAG = "ImageWorker"; /** if enabled, logcat will output the log. */ protected final boolean DEBUG = true & BaseApplicaion.DEBUG; private static final int FADE_IN_TIME = 200; private ImageCache mImageCache; private ImageCache.ImageCacheParams mImageCacheParams; private Bitmap mLoadingBitmap; private boolean mFadeInBitmap = true; private boolean mExitTasksEarly = false; protected boolean mPauseWork = false; private final Object mPauseWorkLock = new Object(); protected Resources mResources; private static final int MESSAGE_CLEAR = 0; private static final int MESSAGE_INIT_DISK_CACHE = 1; private static final int MESSAGE_FLUSH = 2; private static final int MESSAGE_CLOSE = 3; private static final int MESSAGE_CLEAR_MEMORY = 4; /** fetcher?httpclient */ protected Context mContext; /** ??????webview?js?? */ private Object mCallbackSyncLock = new Object(); /** */ private Executor mExecutor = Executors.newFixedThreadPool(2); protected ImageWorker(Context context) { mResources = context.getResources(); mContext = context.getApplicationContext(); } /** * ImageViewdata?url?resId {@link BitmapTaskItem} * ?????? {@link BitmapTaskItem} * {@link #processBitmap(Object)} * * @param data * @param imageView */ public void loadImage(Object data, ImageView imageView) { loadImageInternal(new BitmapTaskItem(data), imageView); } /** * Load an image specified by the data parameter into an ImageView (override * {@link ImageWorker#processBitmap(Object)} to define the processing * logic). A memory and disk cache will be used if an {@link ImageCache} has * been added using * {@link ImageWorker#addImageCache(FragmentManager, ImageCache.ImageCacheParams)} * . If the image is found in the memory cache, it is set immediately, * otherwise an {@link AsyncTask} will be created to asynchronously load the * bitmap. * * @param item * The loadtask of the image to download. * @param imageView * The ImageView to bind the downloaded image to. */ final protected void loadImageInternal(BitmapTaskItem item, ImageView imageView) { if (item == null || item.mDataSource == null || imageView == null) { return; } // ? if (item.mDataSource instanceof String && TextUtils.isEmpty((CharSequence) item.mDataSource)) { return; } // resId?s if (item.mDataSource instanceof Integer && (Integer) item.mDataSource == 0) { return; } BitmapDrawable value = null; if (mImageCache != null) { value = mImageCache.getBitmapFromMemCache(String.valueOf(item.mDataSource)); } if (value != null) { // Bitmap found in memory cache // Bug fix by XuWei 2013-09-09 // Drawable?bug?ViewDrawable??Drawable Drawable copyDrawable = new BitmapDrawable(mResources, value.getBitmap()); imageView.setImageDrawable(copyDrawable); } else if (cancelPotentialWork(item.mDataSource, imageView)) { byte[] chunk = null; if (mLoadingBitmap != null) { chunk = mLoadingBitmap.getNinePatchChunk(); } final BitmapWorkerTask task = new BitmapWorkerTask(imageView); if (chunk == null) { final AsyncBitmapDrawable asyncBitmapDrawable = new AsyncBitmapDrawable(mResources, mLoadingBitmap, task); imageView.setImageDrawable(asyncBitmapDrawable); } else { final AsyncNinePatchDrawable.NinePatchChunk npc = AsyncNinePatchDrawable.NinePatchChunk .deserialize(chunk); final AsyncNinePatchDrawable asyncNinePatchDrawable = new AsyncNinePatchDrawable(mResources, mLoadingBitmap, chunk, npc.mPaddings, null, task); imageView.setImageDrawable(asyncNinePatchDrawable); } // NOTE: This uses a custom version of AsyncTask that has been // pulled from the // framework and slightly modified. Refer to the docs at the top of // the class // for more info on what was changed. task.executeOnExecutor(mExecutor, item); } } /** * Set placeholder bitmap that shows when the the background thread is * running. * * @param bitmap */ public void setLoadingImage(Bitmap bitmap) { mLoadingBitmap = bitmap; } /** * Set placeholder bitmap that shows when the the background thread is * running. * * @param resId */ public void setLoadingImage(int resId) { mLoadingBitmap = BitmapFactory.decodeStream(mResources.openRawResource(resId)); } /** * Adds an {@link ImageCache} to this {@link ImageWorker} to handle disk and * memory bitmap caching. * * @param fragmentManager * @param cacheParams * The cache parameters to use for the image cache. */ public void addImageCache(FragmentManager fragmentManager, ImageCache.ImageCacheParams cacheParams) { mImageCacheParams = cacheParams; mImageCache = ImageCache.getInstance(fragmentManager, mImageCacheParams); new CacheAsyncTask().execute(MESSAGE_INIT_DISK_CACHE); } /** * Adds an {@link ImageCache} to this {@link ImageWorker} to handle disk and * memory bitmap caching. * * @param activity * @param diskCacheDirectoryName * See * {@link ImageCache.ImageCacheParams#ImageCacheParams(Context, String)} * . */ public void addImageCache(FragmentActivity activity, String diskCacheDirectoryName) { mImageCacheParams = new ImageCache.ImageCacheParams(activity, diskCacheDirectoryName); mImageCache = ImageCache.getInstance(activity.getSupportFragmentManager(), mImageCacheParams); new CacheAsyncTask().execute(MESSAGE_INIT_DISK_CACHE); } /** * If set to true, the image will fade-in once it has been loaded by the * background thread. */ public void setImageFadeIn(boolean fadeIn) { mFadeInBitmap = fadeIn; } public void setExitTasksEarly(boolean exitTasksEarly) { mExitTasksEarly = exitTasksEarly; setPauseWork(false); } /** * Subclasses should override this to define any processing or work that * must happen to produce the final bitmap. This will be executed in a * background thread and be long running. For example, you could resize a * large bitmap here, or pull down an image from the network. * * @param taskItem * The data to identify which image to process, as provided by * {@link ImageWorker#loadImageInternal(BitmapTaskItem, ImageView)} * @param processCallback * the callback of process progress * @return The processed bitmap */ protected abstract Bitmap processBitmap(BitmapTaskItem taskItem, OnProcessProgressUpdate processCallback); /** * @return The {@link ImageCache} object currently being used by this * ImageWorker. */ protected ImageCache getImageCache() { return mImageCache; } /** * * * @param imageView * @param drawable */ public static void setFadeInDrawable(ImageView imageView, Drawable drawable) { // Bug fix by XuWei 2013-09-09 // Drawable?bug?ViewDrawable??Drawable Drawable copyDrawable = new BitmapDrawable(imageView.getContext().getResources(), ((BitmapDrawable) drawable).getBitmap()); // Transition drawable with a transparent drawable and the final // drawable final TransitionDrawable td = new TransitionDrawable( new Drawable[] { new ColorDrawable(android.R.color.transparent), copyDrawable }); imageView.setImageDrawable(td); td.startTransition(FADE_IN_TIME); } /** * Cancels any pending work attached to the provided ImageView. * * @param imageView */ public static void cancelWork(ImageView imageView) { final BitmapWorkerTask bitmapWorkerTask = getBitmapWorkerTask(imageView); if (bitmapWorkerTask != null) { bitmapWorkerTask.cancel(true); if (BuildConfig.DEBUG) { final Object bitmapData = bitmapWorkerTask.mBitmapTaskItem.mDataSource; Log.d(TAG, "cancelWork - cancelled work for " + bitmapData); } } } /** * Returns true if the current work has been canceled or if there was no * work in progress on this image view. Returns false if the work in * progress deals with the same data. The work is not stopped in that case. */ public static boolean cancelPotentialWork(Object data, ImageView imageView) { final BitmapWorkerTask bitmapWorkerTask = getBitmapWorkerTask(imageView); if (bitmapWorkerTask != null) { final BitmapTaskItem bitmapTaskItem = bitmapWorkerTask.mBitmapTaskItem; if (bitmapTaskItem == null || bitmapTaskItem.mDataSource == null || !bitmapTaskItem.mDataSource.equals(data)) { bitmapWorkerTask.cancel(true); if (BuildConfig.DEBUG) { Log.d(TAG, "cancelPotentialWork - cancelled work for " + data); } } else { // The same work is already in progress. return false; } } return true; } /** * @param imageView * Any imageView * @return Retrieve the currently active work task (if any) associated with * this imageView. null if there is no such task. */ private static BitmapWorkerTask getBitmapWorkerTask(ImageView imageView) { if (imageView != null) { final Drawable drawable = imageView.getDrawable(); if (drawable instanceof AsyncBitmapDrawable) { final AsyncBitmapDrawable asyncDrawable = (AsyncBitmapDrawable) drawable; return asyncDrawable.getBitmapWorkerTask(); } else if (drawable instanceof AsyncNinePatchDrawable) { final AsyncNinePatchDrawable asyncDrawable = (AsyncNinePatchDrawable) drawable; return asyncDrawable.getBitmapWorkerTask(); } } return null; } /** * The actual AsyncTask that will asynchronously process the image. */ private class BitmapWorkerTask extends AsyncTask<BitmapTaskItem, Integer, BitmapDrawable> implements OnProcessProgressUpdate { /** ?? */ private BitmapTaskItem mBitmapTaskItem; private final WeakReference<ImageView> imageViewReference; public BitmapWorkerTask(ImageView imageView) { imageViewReference = new WeakReference<ImageView>(imageView); } /** * Background processing. */ @Override protected BitmapDrawable doInBackground(BitmapTaskItem... params) { if (BuildConfig.DEBUG) { Log.d(TAG, "doInBackground - starting work"); } mBitmapTaskItem = params[0]; final String dataString = String.valueOf(mBitmapTaskItem.mDataSource); Bitmap bitmap = null; BitmapDrawable drawable = null; // Wait here if work is paused and the task is not cancelled synchronized (mPauseWorkLock) { while (mPauseWork && !isCancelled()) { try { mPauseWorkLock.wait(); } catch (InterruptedException e) { } } } // If the image cache is available and this task has not been // cancelled by another // thread and the ImageView that was originally bound to this task // is still bound back // to this task and our "exit early" flag is not set then try and // fetch the bitmap from // the cache if (mImageCache != null && !isCancelled() && getAttachedImageView() != null && !mExitTasksEarly) { bitmap = mImageCache.getBitmapFromDiskCache(dataString); } // If the bitmap was not found in the cache and this task has not // been cancelled by // another thread and the ImageView that was originally bound to // this task is still // bound back to this task and our "exit early" flag is not set, // then call the main // process method (as implemented by a subclass) if (bitmap == null && !isCancelled() && getAttachedImageView() != null && !mExitTasksEarly) { bitmap = processBitmap(mBitmapTaskItem, this); } // If the bitmap was processed and the image cache is available, // then add the processed // bitmap to the cache for future use. Note we don't check if the // task was cancelled // here, if it was, and the thread is still running, we may as well // add the processed // bitmap to our cache as it might be used again in the future if (bitmap != null) { // ?BitmapDrawable? // if (Utils.hasHoneycomb()) { // // Running on Honeycomb or newer, so wrap in a standard // // BitmapDrawable // drawable = new BitmapDrawable(mResources, bitmap); // } else { // Running on Gingerbread or older, so wrap in a // RecyclingBitmapDrawable // which will recycle automagically drawable = new RecyclingBitmapDrawable(mResources, bitmap); // } if (mImageCache != null) { mImageCache.addBitmapToCache(dataString, drawable); } } if (BuildConfig.DEBUG) { Log.d(TAG, "doInBackground - finished work"); } return drawable; } /** * Once the image is processed, associates it to the imageView */ @Override protected void onPostExecute(BitmapDrawable value) { // if cancel was called on this task or the "exit early" flag is set // then we're done if (isCancelled() || mExitTasksEarly) { value = null; } final ImageView imageView = getAttachedImageView(); if (value != null && imageView != null) { if (BuildConfig.DEBUG) { Log.d(TAG, "onPostExecute - setting bitmap"); } setImageDrawable(imageView, value); } } @Override protected void onProgressUpdate(Integer... values) { if (isCancelled() || mExitTasksEarly) { return; } final ImageView imageView = getAttachedImageView(); if (values != null && imageView != null && imageView instanceof ProgressImageView) { ((ProgressImageView) imageView).setProgress(values[0]); } } @Override public void updateProgress(int progress) { publishProgress(progress); } @Override protected void onCancelled(BitmapDrawable value) { super.onCancelled(value); synchronized (mPauseWorkLock) { mPauseWorkLock.notifyAll(); } } /** * Returns the ImageView associated with this task as long as the * ImageView's task still points to this task as well. Returns null * otherwise. */ private ImageView getAttachedImageView() { final ImageView imageView = imageViewReference.get(); final BitmapWorkerTask bitmapWorkerTask = getBitmapWorkerTask(imageView); if (this == bitmapWorkerTask) { return imageView; } return null; } } /** * A custom Drawable that will be attached to the imageView while the work * is in progress. Contains a reference to the actual worker task, so that * it can be stopped if a new binding is required, and makes sure that only * the last started worker process can bind its result, independently of the * finish order. */ private static class AsyncBitmapDrawable extends BitmapDrawable { private final WeakReference<BitmapWorkerTask> bitmapWorkerTaskReference; public AsyncBitmapDrawable(Resources res, Bitmap bitmap, BitmapWorkerTask bitmapWorkerTask) { super(res, bitmap); bitmapWorkerTaskReference = new WeakReference<BitmapWorkerTask>(bitmapWorkerTask); } public BitmapWorkerTask getBitmapWorkerTask() { return bitmapWorkerTaskReference.get(); } } /** * nine patch drawable * * @author Calvin * */ private static class AsyncNinePatchDrawable extends NinePatchDrawable { private final WeakReference<BitmapWorkerTask> bitmapWorkerTaskReference; public BitmapWorkerTask getBitmapWorkerTask() { return bitmapWorkerTaskReference.get(); } public AsyncNinePatchDrawable(Resources res, Bitmap bitmap, byte[] chunk, Rect padding, String srcName, BitmapWorkerTask bitmapWorkerTask) { super(res, bitmap, chunk, padding, srcName); bitmapWorkerTaskReference = new WeakReference<BitmapWorkerTask>(bitmapWorkerTask); } /** * NinePatchChunk * * @author Calvin * */ static class NinePatchChunk { public static final int NO_COLOR = 0x00000001; public static final int TRANSPARENT_COLOR = 0x00000000; public Rect mPaddings = new Rect(); public int mDivX[]; public int mDivY[]; public int mColor[]; private static void readIntArray(int[] data, ByteBuffer buffer) { for (int i = 0, n = data.length; i < n; ++i) { data[i] = buffer.getInt(); } } private static void checkDivCount(int length) { if (length == 0 || (length & 0x01) != 0) { throw new RuntimeException("invalid nine-patch: " + length); } } public static NinePatchChunk deserialize(byte[] data) { ByteBuffer byteBuffer = ByteBuffer.wrap(data).order(ByteOrder.nativeOrder()); byte wasSerialized = byteBuffer.get(); if (wasSerialized == 0) return null; NinePatchChunk chunk = new NinePatchChunk(); chunk.mDivX = new int[byteBuffer.get()]; chunk.mDivY = new int[byteBuffer.get()]; chunk.mColor = new int[byteBuffer.get()]; checkDivCount(chunk.mDivX.length); checkDivCount(chunk.mDivY.length); // skip 8 bytes byteBuffer.getInt(); byteBuffer.getInt(); chunk.mPaddings.left = byteBuffer.getInt(); chunk.mPaddings.right = byteBuffer.getInt(); chunk.mPaddings.top = byteBuffer.getInt(); chunk.mPaddings.bottom = byteBuffer.getInt(); // skip 4 bytes byteBuffer.getInt(); readIntArray(chunk.mDivX, byteBuffer); readIntArray(chunk.mDivY, byteBuffer); readIntArray(chunk.mColor, byteBuffer); return chunk; } } } /** * Called when the processing is complete and the final drawable should be * set on the ImageView. * * @param imageView * @param drawable */ private void setImageDrawable(ImageView imageView, Drawable drawable) { // Bug fix by XuWei 2013-09-09 // Drawable?bug?ViewDrawable??Drawable Drawable copyDrawable = new BitmapDrawable(mResources, ((BitmapDrawable) drawable).getBitmap()); if (mFadeInBitmap) { // Transition drawable with a transparent drawable and the final // drawable final TransitionDrawable td = new TransitionDrawable( new Drawable[] { new ColorDrawable(android.R.color.transparent), copyDrawable }); // Set background to loading bitmap imageView.setImageDrawable(new BitmapDrawable(mResources, mLoadingBitmap)); imageView.setImageDrawable(td); td.startTransition(FADE_IN_TIME); } else { imageView.setImageDrawable(copyDrawable); } } /** * Pause any ongoing background work. This can be used as a temporary * measure to improve performance. For example background work could be * paused when a ListView or GridView is being scrolled using a * {@link android.widget.AbsListView.OnScrollListener} to keep scrolling * smooth. * <p> * If work is paused, be sure setPauseWork(false) is called again before * your fragment or activity is destroyed (for example during * {@link android.app.Activity#onPause()}), or there is a risk the * background thread will never finish. */ public void setPauseWork(boolean pauseWork) { synchronized (mPauseWorkLock) { mPauseWork = pauseWork; if (!mPauseWork) { mPauseWorkLock.notifyAll(); } } } /** * ? * * @author Calvin * */ protected class CacheAsyncTask extends AsyncTask<Object, Void, Void> { @Override protected Void doInBackground(Object... params) { switch ((Integer) params[0]) { case MESSAGE_CLEAR: clearCacheInternal(); break; case MESSAGE_INIT_DISK_CACHE: initDiskCacheInternal(); break; case MESSAGE_FLUSH: flushCacheInternal(); break; case MESSAGE_CLOSE: closeCacheInternal(); break; case MESSAGE_CLEAR_MEMORY: clearMemoryCacheInternal(); break; } return null; } } /** * ? */ protected void initDiskCacheInternal() { if (mImageCache != null) { mImageCache.initDiskCache(); } } /** * ?? */ protected void clearCacheInternal() { if (mImageCache != null) { mImageCache.clearCache(); } } /** * */ protected void clearMemoryCacheInternal() { if (mImageCache != null) { mImageCache.clearMemoryCache(); } } /** * ? */ protected void flushCacheInternal() { if (mImageCache != null) { mImageCache.flush(); } } /** * */ protected void closeCacheInternal() { if (mImageCache != null) { mImageCache.close(); mImageCache = null; } } public void clearCache() { new CacheAsyncTask().execute(MESSAGE_CLEAR); } public void flushCache() { new CacheAsyncTask().execute(MESSAGE_FLUSH); } public void closeCache() { new CacheAsyncTask().execute(MESSAGE_CLOSE); } public void clearMemoryCache() { new CacheAsyncTask().execute(MESSAGE_CLEAR_MEMORY); } /* * 2013-5-28 ??uri */ /** * ??ImageViewBitmapUri {@link BitmapTaskItem} * ?????? {@link BitmapTaskItem} * {@link #processBitmap(Object)} * * @param item * The loadtask of the image to download. * @param callback * The BitmapWorkCallbackTaskContainer to sync with the bitmap. * @see ImageFilepathCallback * @see ImageBitmapCallback */ public void loadImage(Object data, BitmapWorkCallbackTaskContainer callback) { loadImageInternal(new BitmapTaskItem(data), callback); } /** * ??ImageViewBitmapUri * * @param item * The loadtask of the image to download. * @param callback * The BitmapWorkCallbackTaskContainer to sync with the bitmap. * @see ImageFilepathCallback * @see ImageBitmapCallback */ final protected void loadImageInternal(BitmapTaskItem item, BitmapWorkCallbackTaskContainer callback) { if (item == null || item.mDataSource == null || callback == null) { return; } // ? if (item.mDataSource instanceof String && TextUtils.isEmpty((CharSequence) item.mDataSource)) { return; } // resId?s if (item.mDataSource instanceof Integer && (Integer) item.mDataSource == 0) { return; } BitmapDrawable value = null; if (mImageCache != null) { value = mImageCache.getBitmapFromMemCache(String.valueOf(item.mDataSource)); } else if (callback instanceof ImageFilepathCallback) { Log.e(TAG, "ImageFilepathCallback need a ImageCache to get the image filepath."); return; } if (value != null && callback instanceof ImageWorkerDrawableCallback) { // Bitmap found in memory cache // Bug fix by XuWei 2013-09-09 // Drawable?bug?ViewDrawable??Drawable Drawable copyDrawable = new BitmapDrawable(mResources, value.getBitmap()); ((ImageWorkerDrawableCallback) callback).getImageDrawable(copyDrawable); } else if (cancelPotentialWork(item.mDataSource, callback)) { final BitmapWorkerCallbackTask task = new BitmapWorkerCallbackTask(callback); callback.setBitmapWorkerCallbackTask(task); // NOTE: This uses a custom version of AsyncTask that has been // pulled from the // framework and slightly modified. Refer to the docs at the top of // the class // for more info on what was changed. task.executeOnExecutor(mExecutor, item); } } /** * Returns true if the current work has been canceled or if there was no * work in progress on this callback. Returns false if the work in progress * deals with the same data. The work is not stopped in that case. */ public static boolean cancelPotentialWork(Object data, BitmapWorkCallbackTaskContainer callback) { final BitmapWorkerCallbackTask bitmapWorkerTask = callback.getBitmapWorkerCallbackTask(); if (bitmapWorkerTask != null) { final BitmapTaskItem bitmapTaskItem = bitmapWorkerTask.mBitmapTaskItem; if (bitmapTaskItem == null || bitmapTaskItem.mDataSource == null || !bitmapTaskItem.mDataSource.equals(data)) { bitmapWorkerTask.cancel(true); if (BuildConfig.DEBUG) { Log.d(TAG, "cancelPotentialWork - cancelled work for " + data); } } else { // The same work is already in progress. return false; } } return true; } /** * ?? * * @author Calvin * */ private class BitmapWorkerCallbackTask extends AsyncTask<BitmapTaskItem, Integer, Object[]> implements OnProcessProgressUpdate { private BitmapTaskItem mBitmapTaskItem; private BitmapWorkCallbackTaskContainer callback; public BitmapWorkerCallbackTask(BitmapWorkCallbackTaskContainer callback) { this.callback = callback; } /** * Background processing. */ @Override protected Object[] doInBackground(BitmapTaskItem... params) { if (BuildConfig.DEBUG) { Log.d(TAG, "doInBackground - starting work"); } mBitmapTaskItem = params[0]; final String dataString = String.valueOf(mBitmapTaskItem.mDataSource); Bitmap bitmap = null; BitmapDrawable drawable = null; String filepath = null; // Wait here if work is paused and the task is not cancelled synchronized (mPauseWorkLock) { while (mPauseWork && !isCancelled()) { try { mPauseWorkLock.wait(); } catch (InterruptedException e) { } } } // If the image cache is available and this task has not been // cancelled by another // thread and the ImageView that was originally bound to this task // is still bound back // to this task and our "exit early" flag is not set then try and // fetch the bitmap from // the cache if (mImageCache != null && !isCancelled() && getAttachedCallback() != null && !mExitTasksEarly) { bitmap = mImageCache.getBitmapFromDiskCache(dataString); } // If the bitmap was not found in the cache and this task has not // been cancelled by // another thread and the ImageView that was originally bound to // this task is still // bound back to this task and our "exit early" flag is not set, // then call the main // process method (as implemented by a subclass) if (bitmap == null && !isCancelled() && getAttachedCallback() != null && !mExitTasksEarly) { bitmap = processBitmap(mBitmapTaskItem, this); } // If the bitmap was processed and the image cache is available, // then add the processed // bitmap to the cache for future use. Note we don't check if the // task was cancelled // here, if it was, and the thread is still running, we may as well // add the processed // bitmap to our cache as it might be used again in the future if (bitmap != null) { // ?BitmapDrawable? // if (Utils.hasHoneycomb()) { // // Running on Honeycomb or newer, so wrap in a standard // // BitmapDrawable // drawable = new BitmapDrawable(mResources, bitmap); // } else { // Running on Gingerbread or older, so wrap in a // RecyclingBitmapDrawable // which will recycle automagically drawable = new RecyclingBitmapDrawable(mResources, bitmap); // } if (mImageCache != null) { mImageCache.addBitmapToCache(dataString, drawable); } // bitmap??? if (bitmap != null && mImageCache != null) { try { filepath = Uri.fromFile(new File(mImageCache.getBitmapFilepathFromDiskCache(dataString))) .toString(); } catch (Exception e) { Log.e(TAG, e); } } } if (BuildConfig.DEBUG) { Log.d(TAG, "doInBackground - finished work"); } return new Object[] { drawable, filepath }; } /** * Once the image is processed, associates it to the callback */ @Override protected void onPostExecute(Object[] values) { // if cancel was called on this task or the "exit early" flag is set // then we're done if (isCancelled() || mExitTasksEarly) { values[0] = null; values[1] = null; values = null; } final BitmapWorkCallbackTaskContainer callback = getAttachedCallback(); if (values != null && callback != null) { if (BuildConfig.DEBUG) { Log.d(TAG, "onPostExecute - setting bitmap"); } // js?img src??js???? synchronized (mCallbackSyncLock) { if (callback instanceof ImageFilepathCallback) { if (values[1] != null) { ((ImageFilepathCallback) callback).getImageFilePath((String) values[1]); } } else if (callback instanceof ImageDrawableCallback) { BitmapDrawable result = (BitmapDrawable) values[0]; if (result != null) { ((ImageDrawableCallback) callback).getImageDrawable(result); } } } } } @Override protected void onProgressUpdate(Integer... values) { final BitmapWorkCallbackTaskContainer callback = getAttachedCallback(); if (values != null && callback != null) { callback.updateProgress(values[0]); } } @Override public void updateProgress(int progress) { publishProgress(progress); } @Override protected void onCancelled(Object[] value) { super.onCancelled(value); synchronized (mPauseWorkLock) { mPauseWorkLock.notifyAll(); } } /** * Returns the Callback associated with this task as long as the * Callback's task still points to this task as well. Returns null * otherwise. */ private BitmapWorkCallbackTaskContainer getAttachedCallback() { if (callback == null) { return null; } final BitmapWorkerCallbackTask bitmapWorkerTask = callback.getBitmapWorkerCallbackTask(); if (this == bitmapWorkerTask) { return callback; } return null; } } /** * loadImage?BitmapWorkerCallbackTask * * @author Calvin * */ protected static abstract class BitmapWorkCallbackTaskContainer { /** */ private WeakReference<BitmapWorkerCallbackTask> mTaskWeakReference; /** * task???oom * * @param task */ private void setBitmapWorkerCallbackTask(BitmapWorkerCallbackTask task) { mTaskWeakReference = new WeakReference<BitmapWorkerCallbackTask>(task); } private BitmapWorkerCallbackTask getBitmapWorkerCallbackTask() { if (mTaskWeakReference == null) { return null; } return mTaskWeakReference.get(); } /** * * * @param progress */ public void updateProgress(int progress) { // override it if need } } /** * ?Uri * * @author Calvin * */ public static abstract class ImageFilepathCallback extends BitmapWorkCallbackTaskContainer implements ImageWorkerBitmapPathCallback { } /** * ?bitmap * * @author Calvin * */ public static abstract class ImageDrawableCallback extends BitmapWorkCallbackTaskContainer implements ImageWorkerDrawableCallback { } /** * ?Uri? * * @author Calvin * */ private interface ImageWorkerBitmapPathCallback { public void getImageFilePath(String filePath); } /** * ?drawable? * * @author Calvin * */ private interface ImageWorkerDrawableCallback { public void getImageDrawable(Drawable drawable); } /* * 2013-7-11item??? */ protected class BitmapTaskItem { /** ?? */ protected Object mDataSource; /** * * * @param dataSource */ protected BitmapTaskItem(Object dataSource) { mDataSource = dataSource; } } /* * 2013-7-17AsyncTaskonProgressUpdateprotected * ?processBitmap */ protected interface OnProcessProgressUpdate { /** * * * @param progress */ void updateProgress(int progress); } }