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.ccz.viewimages.displayingbitmaps.util; import android.app.FragmentManager; import android.content.Context; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Matrix; import android.graphics.drawable.BitmapDrawable; import android.graphics.drawable.ColorDrawable; import android.graphics.drawable.Drawable; import android.graphics.drawable.TransitionDrawable; import android.util.Log; import android.view.View; import android.widget.ImageView; import com.ccz.viewimages.BuildConfig; import com.ccz.viewimages.R; import com.ccz.viewimages.ScrollingActivity; import com.ccz.viewimages.media.MediaItem; import java.lang.ref.WeakReference; import java.util.ArrayList; //import com.example.android.common.logger.Log; //import android.support.v4.app.FragmentActivity; //import android.support.v4.app.FragmentManager; //import com.example.android.displayingbitmaps.BuildConfig; /** * 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"; private static final int FADE_IN_TIME = 500; private ImageCache mImageCache; private ImageCache.ImageCacheParams mImageCacheParams; protected Bitmap mLoadingBitmap; protected Bitmap mLoadingColorBitmap; protected ArrayList<String> mdColors = new ArrayList(); protected int[] mColors; private boolean mFadeInBitmap = true; private boolean mExitTasksEarly = false; protected boolean mPauseWork = false; private final Object mPauseWorkLock = new Object(); protected Resources mResources; protected Context mContext; 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 static final int THUMB_MODE_DEFAULT = 0; //0: default, no buffer, 1:step1 (doing micro) 2: step 2(doing mini) public static final int THUMB_MODE_WBUFFER_STEP1 = 1; public static final int THUMB_MODE_WBUFFER_STEP2 = 2; protected ImageWorker(Context context) { mResources = context.getResources(); mContext = context; } /** * 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(android.support.v4.app.FragmentManager, ImageCache.ImageCacheParams)}. If the * image is found in the memory cache, it is set immediately, otherwise an {@link CustomAsyncTask} * 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. */ public void loadImage(Object data, ImageView imageView) { loadImageWithDoubleThumb(data, imageView, false); } public void loadImageWithDoubleThumb(Object data, ImageView imageView, boolean needDoubleThumb) { if (data == null) { return; } BitmapDrawable value = null; if (mImageCache != null) { value = mImageCache.getBitmapFromMemCache(String.valueOf(data)); } if (value != null) { // Bitmap found in memory cache imageView.setImageDrawable(value); } else if (cancelPotentialWork(data, imageView)) { //BEGIN_INCLUDE(execute_background_task) final BitmapWorkerTask task = new BitmapWorkerTask(data, imageView); if (needDoubleThumb) { task.enableDoubleThumb(); } final AsyncDrawable asyncDrawable = new AsyncDrawable(mResources, mLoadingBitmap, task); imageView.setImageDrawable(asyncDrawable); // NOTE: This uses a custom version of CustomAsyncTask 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(CustomAsyncTask.DUAL_THREAD_EXECUTOR); //END_INCLUDE(execute_background_task) } } /** * 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 {@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(android.app.FragmentManager activity, ImageCache.ImageCacheParams 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 data The data to identify which image to process, as provided by * {@link ImageWorker#loadImage(Object, ImageView)} * @return The processed bitmap */ protected abstract Bitmap processBitmap(Object data); /** * @return The {@link ImageCache} object currently being used by this ImageWorker. */ protected ImageCache getImageCache() { return mImageCache; } /** * 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.mData; 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) { //BEGIN_INCLUDE(cancel_potential_work) final BitmapWorkerTask bitmapWorkerTask = getBitmapWorkerTask(imageView); if (bitmapWorkerTask != null) { final Object bitmapData = bitmapWorkerTask.mData; 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; //END_INCLUDE(cancel_potential_work) } /** * @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 CustomAsyncTask that will asynchronously process the image. */ private class BitmapWorkerTask extends CustomAsyncTask<Void, Void, BitmapDrawable> { private Object mData; protected int mDoubleThumbingLevel = THUMB_MODE_DEFAULT; private final WeakReference<ImageView> imageViewReference; public BitmapWorkerTask(Object data, ImageView imageView) { mDoubleThumbingLevel = THUMB_MODE_DEFAULT; //we only use this in photo, so we use 0 mData = data; imageViewReference = new WeakReference<ImageView>(imageView); } /** * Background processing. */ @Override protected BitmapDrawable doInBackground(Void... params) { //BEGIN_INCLUDE(load_bitmap_in_background) if (BuildConfig.DEBUG) { Log.d(TAG, "doInBackground - starting work"); } final String dataString = String.valueOf(mData); // final String dataString = (mData instanceof MediaItem) ? ((MediaItem) mData).getCacheKey() : String.valueOf(mData); //bling bling Bitmap bitmap = null; BitmapDrawable drawable = null; // Wait here if work is paused and the task is not cancelled synchronized (mPauseWorkLock) { while (mPauseWork && !isCancelled() && THUMB_MODE_WBUFFER_STEP2 == mDoubleThumbingLevel) { try { //smith: if user scrolling, w'd better ignore the large thumb. if (isThumbnailSkipped()) { return null; } mPauseWorkLock.wait(100); } catch (InterruptedException e) { } } } //smith: if user scrolling, w'd better ignore the large thumb. if (isThumbnailSkipped()) { return null; } if (mData instanceof MediaItem) { MediaItem item = (MediaItem) mData; if (item.getSource().equals(MediaItem.SOURCE_SHARE) || item.getSource().equals(MediaItem.SOURCE_AUSTOR)) { mDoubleThumbingLevel = THUMB_MODE_DEFAULT; // 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_option_menu // process method (as implemented by a subclass) if (bitmap == null && !isCancelled() && getAttachedImageView() != null && !mExitTasksEarly) { bitmap = processBitmap(item.getThumbnailPath()); } } else { //rotate int degree = ((MediaItem) mData).getOrientation(); Bitmap microBitmap = null; if (THUMB_MODE_WBUFFER_STEP1 == mDoubleThumbingLevel) { microBitmap = ((MediaItem) mData).getMicroThumbnail(); } if (null != microBitmap) { bitmap = microBitmap; } else { if (THUMB_MODE_WBUFFER_STEP1 == mDoubleThumbingLevel) mDoubleThumbingLevel = THUMB_MODE_DEFAULT; BitmapFactory.Options option = new BitmapFactory.Options(); option.inPreferredConfig = Bitmap.Config.RGB_565; Bitmap oriBitmap = ((MediaItem) mData).getThumbnail(option); // Bitmap oriBitmap = ((MediaItem) mData).getFullScreenThumbnail(option); if (null == oriBitmap) { option = new BitmapFactory.Options(); option.inPreferredConfig = Bitmap.Config.RGB_565; oriBitmap = BitmapFactory.decodeFile(((MediaItem) mData).getThumbnailPath(), option); } bitmap = oriBitmap; } //smith: if user scrolling, w'd better ignore the large thumb. if (isThumbnailSkipped()) { return null; } if (null != bitmap && bitmap.getWidth() > 0 && bitmap.getHeight() > 0) { Matrix matrix = null; if (0 != degree) { if (null == matrix) matrix = new Matrix(); matrix.postRotate(degree); if (null != matrix) { bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true); } } } } } else { Log.e(TAG, "isn't MediaItem"); } // 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) { // if (FlavorUtils.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 && THUMB_MODE_WBUFFER_STEP1 != mDoubleThumbingLevel) { mImageCache.addBitmapToCache(dataString, drawable); } } if (BuildConfig.DEBUG) { Log.d(TAG, "doInBackground - finished work"); } return drawable; //END_INCLUDE(load_bitmap_in_background) } /** * Once the image is processed, associates it to the imageView */ @Override protected void onPostExecute(BitmapDrawable value) { //BEGIN_INCLUDE(complete_background_work) // 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"); } BitmapDrawable bd = (BitmapDrawable) imageView.getDrawable(); Bitmap b = null; if (null != bd) { b = bd.getBitmap(); } setImageDrawable(imageView, value, b); if (THUMB_MODE_WBUFFER_STEP1 == mDoubleThumbingLevel) { Bitmap bmp = value.getBitmap().copy(value.getBitmap().getConfig(), true); final BitmapWorkerTask task2 = new BitmapWorkerTask(mData, imageView); task2.setDoubleThumbLevel(THUMB_MODE_WBUFFER_STEP2); final AsyncDrawable asyncDrawable2 = new AsyncDrawable(mResources, bmp, task2); imageView.setImageDrawable(asyncDrawable2); task2.executeOnExecutor(CustomAsyncTask.DUAL_THREAD_EXECUTOR_CHANNEL2); } } //END_INCLUDE(complete_background_work) } @Override protected void onCancelled(BitmapDrawable value) { super.onCancelled(value); synchronized (mPauseWorkLock) { mPauseWorkLock.notifyAll(); } } public void enableDoubleThumb() { setDoubleThumbLevel(THUMB_MODE_WBUFFER_STEP1); } private void setDoubleThumbLevel(int level) { mDoubleThumbingLevel = level; } public boolean isThumbnailSkipped() { ImageView imageView = imageViewReference.get(); if (null == imageView) { // Log.e("aaaaaaaaaaa","EXIT AAAAA"); return true; // } else if ((imageView.getTag(R.id.tagID) instanceof ScrollingActivity.GalleryAdapter.ViewHolder) && ((ScrollingActivity.GalleryAdapter.ViewHolder) imageView.getTag(R.id.tagID)).mMediaItem != mData) { //// Log.e("aaaaaaaaaaa","EXIT BBBBB"); // return true; } else if (imageView.getVisibility() != View.VISIBLE && THUMB_MODE_WBUFFER_STEP2 == mDoubleThumbingLevel) { // Log.e("aaaaaaaaaaa","EXIT CCCCC"); return true; } return false; } /** * 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 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(); } } /** * 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) { setImageDrawable(imageView, drawable, null); } private void setImageDrawable(ImageView imageView, Drawable drawable, Bitmap transbitmap) { if (mFadeInBitmap) { // Transition drawable with a transparent drawable and the final drawable final TransitionDrawable td = new TransitionDrawable(new Drawable[] { new ColorDrawable(mResources.getColor(android.R.color.transparent)), drawable }); // Set background to loading bitmap if (null != transbitmap) { imageView.setBackgroundDrawable(new BitmapDrawable(mResources, transbitmap)); } imageView.setImageDrawable(td); td.startTransition(FADE_IN_TIME); } else { imageView.setImageDrawable(drawable); } } /** * 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(); } } } protected class CacheAsyncTask extends CustomAsyncTask<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); } }