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 haipeng.myalbum.imageload; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.InputStream; import java.lang.ref.WeakReference; import android.content.Context; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Color; import android.graphics.drawable.BitmapDrawable; import android.graphics.drawable.ColorDrawable; import android.graphics.drawable.Drawable; import android.graphics.drawable.TransitionDrawable; import android.support.v4.app.FragmentManager; import android.text.TextUtils; import android.util.Log; import android.widget.ImageView; import haipeng.myalbum.BuildConfig; import haipeng.myalbum.Utils.Loger; /** * 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. */ /** * @author zhaohaitao * */ public abstract class ImageWorker { private static final String TAG = "ImageWorker"; 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; public interface ImgLoadCompleteListener { void onLoadComplete(ImageView imgView, Bitmap bitmap, String url); } private ImgLoadCompleteListener mLoadCompleteListener; protected ImageWorker(Context context) { mResources = context.getResources(); } public void setImgLoadCompleteListener(ImgLoadCompleteListener listener) { this.mLoadCompleteListener = listener; } private void notifyLoadComplete(String url, Bitmap bm, ImageView imgView) { if (mLoadCompleteListener != null) { mLoadCompleteListener.onLoadComplete(imgView, bm, url); } } /** * ?bitmap null loadImage */ public Bitmap getBitmapFromMemoryCache(Object data) { Bitmap bitmap = null; if (mImageCache != null) { bitmap = mImageCache.getBitmapFromMemCache(String.valueOf(data)); } return bitmap; } /** * ??bitmap null loadImage */ public Bitmap getBitmapFromDiskCache(Object data) { Bitmap bitmap = null; if (mImageCache != null) { bitmap = mImageCache.getBitmapFromDiskCache(String.valueOf(data)); } if (bitmap != null && mImageCache != null) { mImageCache.addBitmapToCache(String.valueOf(data), bitmap); } return bitmap; } public void addBitmap2Cache(Object data, Bitmap bitmap) { if (data == null || bitmap == null) { return; } if (mImageCache != null) { mImageCache.addBitmapToCache(String.valueOf(data), bitmap); } } /** * Load an image specified by the data parameter into an ImageView (override * {@link ImageWorker(Object)} to define the processing * logic). A memory and disk cache will be used if an {@link ImageCache} has * been set using {@link ImageWorker#setImageCache(ImageCache)}. 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 data * The URL of the image to download. * @param imageView * The ImageView to bind the downloaded image to. * @param loadImgViaMobile * ?true */ public void loadImage(Object data, ImageView imageView, boolean loadImgViaMobile) { if (data == null || TextUtils.isEmpty(data.toString().trim())) { if (mLoadingBitmap != null && imageView != null) imageView.setImageBitmap(mLoadingBitmap); return; } Bitmap bitmap = null; if (mImageCache != null) { bitmap = mImageCache.getBitmapFromMemCache(String.valueOf(data)); } if (bitmap != null) { // Bitmap found in memory cache notifyLoadComplete(String.valueOf(data), bitmap, imageView); imageView.setImageBitmap(bitmap); } else if (cancelPotentialWork(data, imageView)) { final BitmapWorkerTask task = new BitmapWorkerTask(imageView, loadImgViaMobile); final AsyncDrawable asyncDrawable = new AsyncDrawable(mResources, mLoadingBitmap, task); imageView.setImageDrawable(asyncDrawable); // 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(AsyncTask.DUAL_THREAD_EXECUTOR, data); } } /** * Load an image specified by the data parameter into an ImageView (override * {@link ImageWorker(Object)} to define the processing * logic). A memory and disk cache will be used if an {@link ImageCache} has * been set using {@link ImageWorker#setImageCache(ImageCache)}. 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 data * The URL of the image to download. * @param imageView * The ImageView to bind the downloaded image to. * @param loadImgViaMobile * ?true */ public void loadImage(Object data, ImageView imageView, LoadingIndicatorView indicatorView, boolean loadImgViaMobile) { if (data == null || TextUtils.isEmpty(data.toString().trim())) { if (mLoadingBitmap != null && imageView != null) imageView.setImageBitmap(mLoadingBitmap); return; } Bitmap bitmap = null; if (mImageCache != null) { bitmap = mImageCache.getBitmapFromMemCache(String.valueOf(data)); } if (bitmap != null) { // Bitmap found in memory cache notifyLoadComplete(String.valueOf(data), bitmap, imageView); imageView.setImageBitmap(bitmap); indicatorView.onProgressUpdate(100); indicatorView.setAsyncIndicator(null); } else if (cancelPotentialWork(data, imageView)) { final BitmapWorkerTask task = new BitmapWorkerTask(imageView, indicatorView, loadImgViaMobile); final AsyncDrawable asyncDrawable = new AsyncDrawable(mResources, mLoadingBitmap, task); imageView.setImageDrawable(asyncDrawable); final AsyncIndicator asyncIndicator = new AsyncIndicator(task); indicatorView.setAsyncIndicator(asyncIndicator); // 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(AsyncTask.DUAL_THREAD_EXECUTOR, data); } } /** * 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.decodeResource(mResources, resId); } /** * Adds an {@link ImageCache} to this worker in the background (to prevent * disk access on UI thread). * * @param fragmentManager * @param cacheParams */ public void addImageCache(FragmentManager fragmentManager, ImageCache.ImageCacheParams cacheParams) { mImageCacheParams = cacheParams; setImageCache(ImageCache.findOrCreateCache(fragmentManager, mImageCacheParams)); new CacheAsyncTask().execute(MESSAGE_INIT_DISK_CACHE); } public void addImageCache(ImageCache.ImageCacheParams cacheParams) { mImageCacheParams = cacheParams; setImageCache(new ImageCache(cacheParams)); new CacheAsyncTask().execute(MESSAGE_INIT_DISK_CACHE); } /** * Sets the {@link ImageCache} object to use with this ImageWorker. Usually * you will not need to call this directly, instead use * {@link ImageWorker#addImageCache} which will create and add the * {@link ImageCache} object in a background thread (to ensure no disk * access on the main/UI thread). * * @param imageCache */ public void setImageCache(ImageCache imageCache) { mImageCache = imageCache; } /** * 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; } /** * 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 data * The data to identify which image to process, as provided by * {@link ImageWorker(Object, ImageView)} * @return The processed bitmap */ protected abstract Bitmap processBitmap(Object data, BitmapWorkerTask bitmapworkerTask); /** * 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.data; 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 Object bitmapData = bitmapWorkerTask.data; if (bitmapData == null || !bitmapData.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 AsyncDrawable) { final AsyncDrawable asyncDrawable = (AsyncDrawable) drawable; return asyncDrawable.getBitmapWorkerTask(); } } return null; } /** * The actual AsyncTask that will asynchronously process the image. */ protected class BitmapWorkerTask extends AsyncTask<Object, Integer, Bitmap> { private Object data; /* */ private int publishInterval; private boolean needNotify; private final WeakReference<ImageView> imageViewReference; private final WeakReference<LoadingIndicatorView> loadingIndicatorViewRef; /** ?*/ private boolean shouldLoadInMobile; public BitmapWorkerTask(ImageView imageView, boolean shouldLoadInMobile) { imageViewReference = new WeakReference<ImageView>(imageView); loadingIndicatorViewRef = null; needNotify = false; this.shouldLoadInMobile = shouldLoadInMobile; this.publishInterval = 1000; } public BitmapWorkerTask(ImageView imageView, LoadingIndicatorView indicatorView, boolean shouldLoadInMobile) { imageViewReference = new WeakReference<ImageView>(imageView); loadingIndicatorViewRef = new WeakReference<LoadingIndicatorView>(indicatorView); this.needNotify = true; this.shouldLoadInMobile = shouldLoadInMobile; this.publishInterval = 5; } public int getPublishInterval() { return publishInterval; } public boolean isNeedNotify() { return needNotify; } @Override protected void onProgressUpdate(Integer... values) { super.onProgressUpdate(values); int progress = values[0]; if (progress != -1) { final LoadingIndicatorView indicatorView = getAttachedIndicatorView(); if (indicatorView != null) { indicatorView.onProgressUpdate(progress); } } } /** * Background processing. */ @Override protected Bitmap doInBackground(Object... params) { if (BuildConfig.DEBUG) { // Log.d(TAG, "doInBackground - starting work"); } data = params[0]; final String dataString = String.valueOf(data); Bitmap bitmap = 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); Loger.i("not found in memcache, decode from file:" + dataString); // bitmap = ImageUtil.getBitmapByBytes(dataString); try { InputStream inputStream = new FileInputStream(dataString); if (inputStream != null) { bitmap = BitmapFactory.decodeStream(inputStream); } } catch (FileNotFoundException e) { e.printStackTrace(); } } // 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) { // if(!shouldLoadInMobile){ // if(!PhoneStateUtil.isUsingMobileConnect(BaseApplication.getContext())){ // bitmap = processBitmap(params[0], this); // }else{ // Log.i(TAG, "mobile??"); // } // }else{ // bitmap = processBitmap(params[0], 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 && mImageCache != null) { mImageCache.addBitmapToCache(dataString, bitmap); } if (BuildConfig.DEBUG) { // Log.d(TAG, "doInBackground - finished work"); } return bitmap; } /** * Once the image is processed, associates it to the imageView */ @Override protected void onPostExecute(Bitmap bitmap) { // if cancel was called on this task or the "exit early" flag is set // then we're done if (isCancelled() || mExitTasksEarly) { bitmap = null; } final ImageView imageView = getAttachedImageView(); if (bitmap != null && imageView != null) { if (BuildConfig.DEBUG) { Log.d(TAG, "onPostExecute - setting bitmap"); } notifyLoadComplete(String.valueOf(data), bitmap, imageView); setImageBitmap(imageView, bitmap); } final LoadingIndicatorView indicatorView = getAttachedIndicatorView(); if (indicatorView != null) { if (bitmap != null) { indicatorView.onProgressUpdate(100); } else { indicatorView.onProgressUpdate(-1); } indicatorView.setAsyncIndicator(null); } } @Override protected void onCancelled(Bitmap bitmap) { super.onCancelled(bitmap); 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; } private LoadingIndicatorView getAttachedIndicatorView() { if (loadingIndicatorViewRef != null) { final LoadingIndicatorView indicatorView = loadingIndicatorViewRef.get(); if (indicatorView != null) { final AsyncIndicator indicator = indicatorView.getAsyncIndicator(); if (indicator != null) { final BitmapWorkerTask bitmapWorkerTask = indicator.getBitmapWorkerTask(); if (this == bitmapWorkerTask) { return indicatorView; } } } } 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 AsyncDrawable extends BitmapDrawable { private final WeakReference<BitmapWorkerTask> bitmapWorkerTaskReference; public AsyncDrawable(Resources res, Bitmap bitmap, BitmapWorkerTask bitmapWorkerTask) { super(res, bitmap); bitmapWorkerTaskReference = new WeakReference<BitmapWorkerTask>(bitmapWorkerTask); } public BitmapWorkerTask getBitmapWorkerTask() { return bitmapWorkerTaskReference.get(); } } static class AsyncIndicator { private final WeakReference<BitmapWorkerTask> bitmapWorkerTaskReference; public AsyncIndicator(BitmapWorkerTask bitmapWorkerTask) { bitmapWorkerTaskReference = new WeakReference<BitmapWorkerTask>(bitmapWorkerTask); } public BitmapWorkerTask getBitmapWorkerTask() { return bitmapWorkerTaskReference.get(); } } /** * Called when the processing is complete and the final bitmap should be set * on the ImageView. * * @param imageView * @param bitmap */ @SuppressWarnings("deprecation") private void setImageBitmap(ImageView imageView, Bitmap bitmap) { if (mFadeInBitmap) { // Transition drawable with a transparent drwabale and the final // bitmap final TransitionDrawable td = new TransitionDrawable(new Drawable[] { new ColorDrawable(Color.TRANSPARENT), new BitmapDrawable(mResources, bitmap) }); // Set background to loading bitmap imageView.setBackgroundDrawable(new BitmapDrawable(mResources, mLoadingBitmap)); imageView.setImageDrawable(td); td.startTransition(FADE_IN_TIME); } else { imageView.setImageBitmap(bitmap); } } public void setPauseWork(boolean pauseWork) { synchronized (mPauseWorkLock) { mPauseWork = pauseWork; if (!mPauseWork) { mPauseWorkLock.notifyAll(); } } } 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; } return null; } } protected void initDiskCacheInternal() { if (mImageCache != null) { mImageCache.initDiskCache(); } } protected void clearCacheInternal() { if (mImageCache != null) { mImageCache.clearCache(); } } 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); } }