Java tutorial
/* * Copyright 2012 Google Inc. * * 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.android.volley.cache.plus; import java.util.ArrayList; import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.annotation.TargetApi; import android.content.Context; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.drawable.BitmapDrawable; import android.graphics.drawable.ColorDrawable; import android.graphics.drawable.Drawable; import android.graphics.drawable.TransitionDrawable; import android.net.http.AndroidHttpClient; import android.os.Build; import android.support.v4.app.FragmentActivity; import android.widget.ImageView; import com.android.volley.Cache; import com.android.volley.Network; import com.android.volley.RequestQueue; import com.android.volley.cache.DiskLruBasedCache; import com.android.volley.cache.DiskLruBasedCache.ImageCacheParams; import com.android.volley.error.VolleyError; import com.android.volley.misc.NetUtils; import com.android.volley.misc.Utils; import com.android.volley.toolbox.BasicNetwork; import com.android.volley.toolbox.HttpClientStack; import com.android.volley.toolbox.HurlStack; import com.android.volley.toolbox.ImageCache; import com.android.volley.ui.PhotoView; /** * A class that wraps up remote image loading requests using the Volley library combined with a * memory cache. An single instance of this class should be created once when your Activity or * Fragment is created, then use {@link #get(String, android.widget.ImageView)} or one of * the variations to queue the image to be fetched and loaded from the network. Loading images * in a {@link android.widget.ListView} or {@link android.widget.GridView} is also supported but * you must store the {@link com.android.volley.Request} in your ViewHolder type class and pass it * into loadImage to ensure the request is canceled as views are recycled. */ public class SimpleImageLoader extends ImageLoader { private static final ColorDrawable transparentDrawable = new ColorDrawable(android.R.color.transparent); private static final int HALF_FADE_IN_TIME = Utils.ANIMATION_FADE_IN_TIME / 2; private static final String CACHE_DIR = "images"; private ArrayList<Drawable> mPlaceHolderDrawables; private boolean mFadeInImage = true; private int mMaxImageHeight = 0; private int mMaxImageWidth = 0; /** * Creates an ImageLoader with Bitmap memory cache. No default placeholder image will be shown * while the image is being fetched and loaded. */ public SimpleImageLoader(FragmentActivity activity) { super(newRequestQueue(activity, null), BitmapImageCache.getInstance(activity.getSupportFragmentManager()), activity.getResources()); } /** * Creates an ImageLoader with Bitmap memory cache. No default placeholder image will be shown * while the image is being fetched and loaded. */ public SimpleImageLoader(FragmentActivity activity, ImageCacheParams imageCacheParams) { super(newRequestQueue(activity, imageCacheParams), BitmapImageCache.getInstance(activity.getSupportFragmentManager(), imageCacheParams), activity.getResources()); } /** * Creates an ImageLoader with Bitmap memory cache and a default placeholder image while the * image is being fetched and loaded. */ public SimpleImageLoader(FragmentActivity activity, int defaultPlaceHolderResId, ImageCacheParams imageCacheParams) { super(newRequestQueue(activity, imageCacheParams), BitmapImageCache.getInstance(activity.getSupportFragmentManager(), imageCacheParams), activity.getResources()); mPlaceHolderDrawables = new ArrayList<Drawable>(1); mPlaceHolderDrawables .add(defaultPlaceHolderResId == -1 ? null : getResources().getDrawable(defaultPlaceHolderResId)); } /** * Creates an ImageLoader with Bitmap memory cache and a list of default placeholder drawables. */ public SimpleImageLoader(FragmentActivity activity, ArrayList<Drawable> placeHolderDrawables, ImageCacheParams imageCacheParams) { super(newRequestQueue(activity, imageCacheParams), BitmapImageCache.getInstance(activity.getSupportFragmentManager(), imageCacheParams), activity.getResources()); mPlaceHolderDrawables = placeHolderDrawables; } /** * Creates an ImageLoader with Bitmap memory cache and a default placeholder image while the * image is being fetched and loaded. */ public SimpleImageLoader(Context context, int defaultPlaceHolderResId, ImageCacheParams imageCacheParams) { super(newRequestQueue(context, imageCacheParams), BitmapImageCache.getInstance(null, imageCacheParams), context.getResources()); mPlaceHolderDrawables = new ArrayList<Drawable>(1); mPlaceHolderDrawables .add(defaultPlaceHolderResId == -1 ? null : getResources().getDrawable(defaultPlaceHolderResId)); } /** * Creates an ImageLoader with Bitmap memory cache and a list of default placeholder drawables. */ public SimpleImageLoader(Context context, ArrayList<Drawable> placeHolderDrawables, ImageCacheParams imageCacheParams) { super(newRequestQueue(context, imageCacheParams), BitmapImageCache.getInstance(null, imageCacheParams), context.getResources()); mPlaceHolderDrawables = placeHolderDrawables; } /** * Starts processing requests on the {@link RequestQueue}. */ public void startProcessingQueue() { getRequestQueue().start(); } /** * Stops processing requests on the {@link RequestQueue}. */ public void stopProcessingQueue() { getRequestQueue().stop(); } /** * Clears {@link Cache}. */ public void clearCache() { getCache().clear(); } /** * Flushed {@link Cache} and clears {@link ImageCache}. */ public void flushCache() { getImageCache().clear(); getCache().flush(); } /** * Closes {@link Cache}. */ public void closeCache() { getCache().close(); } public void invalidate(String key) { final String cacheKey = getCacheKey(key, mMaxImageWidth, mMaxImageHeight); getImageCache().invalidateBitmap(cacheKey); getCache().invalidate(key, true); } public SimpleImageLoader setFadeInImage(boolean fadeInImage) { mFadeInImage = fadeInImage; return this; } public SimpleImageLoader setMaxImageSize(int maxImageWidth, int maxImageHeight) { mMaxImageWidth = maxImageWidth; mMaxImageHeight = maxImageHeight; return this; } public SimpleImageLoader setMaxImageSize(int maxImageSize) { return setMaxImageSize(maxImageSize, maxImageSize); } public int getMaxImageWidth() { return mMaxImageWidth; } public int getMaxImageHeight() { return mMaxImageHeight; } //Get public ImageContainer get(String requestUrl, ImageView imageView) { return get(requestUrl, imageView, 0); } public ImageContainer get(String requestUrl, ImageView imageView, int maxImageWidth, int maxImageHeight) { return get(requestUrl, imageView, mPlaceHolderDrawables != null ? mPlaceHolderDrawables.get(0) : null, maxImageWidth, maxImageHeight); } public ImageContainer get(String requestUrl, ImageView imageView, int placeHolderIndex) { return get(requestUrl, imageView, mPlaceHolderDrawables != null ? mPlaceHolderDrawables.get(placeHolderIndex) : null, mMaxImageWidth, mMaxImageHeight); } public ImageContainer get(String requestUrl, ImageView imageView, Drawable placeHolder) { return get(requestUrl, imageView, placeHolder, mMaxImageWidth, mMaxImageHeight); } public ImageContainer get(String requestUrl, ImageView imageView, Drawable placeHolder, int maxWidth, int maxHeight) { // Find any old image load request pending on this ImageView (in case this view was // recycled) ImageContainer imageContainer = imageView.getTag() != null && imageView.getTag() instanceof ImageContainer ? (ImageContainer) imageView.getTag() : null; // Find image url from prior request String recycledImageUrl = imageContainer != null ? imageContainer.getRequestUrl() : null; // If the new requestUrl is null or the new requestUrl is different to the previous // recycled requestUrl if (requestUrl == null || !requestUrl.equals(recycledImageUrl)) { if (imageContainer != null) { // Cancel previous image request imageContainer.cancelRequest(); imageView.setTag(null); } if (requestUrl != null) { // Queue new request to fetch image imageContainer = get(requestUrl, getImageListener(getResources(), imageView, placeHolder, mFadeInImage), maxWidth, maxHeight); // Store request in ImageView tag imageView.setTag(imageContainer); } else { if (!(imageView instanceof PhotoView)) { imageView.setImageDrawable(placeHolder); } imageView.setTag(null); } } return imageContainer; } //Set public ImageContainer set(String requestUrl, ImageView imageView, Bitmap bitmap) { return set(requestUrl, imageView, 0, bitmap); } public ImageContainer set(String requestUrl, ImageView imageView, int placeHolderIndex, Bitmap bitmap) { return set(requestUrl, imageView, mPlaceHolderDrawables != null ? mPlaceHolderDrawables.get(placeHolderIndex) : null, mMaxImageWidth, mMaxImageHeight, bitmap); } public ImageContainer set(String requestUrl, ImageView imageView, Drawable placeHolder, Bitmap bitmap) { return set(requestUrl, imageView, placeHolder, mMaxImageWidth, mMaxImageHeight, bitmap); } public ImageContainer set(String requestUrl, ImageView imageView, Drawable placeHolder, int maxWidth, int maxHeight, Bitmap bitmap) { // Find any old image load request pending on this ImageView (in case this view was // recycled) ImageContainer imageContainer = imageView.getTag() != null && imageView.getTag() instanceof ImageContainer ? (ImageContainer) imageView.getTag() : null; // Find image url from prior request //String recycledImageUrl = imageContainer != null ? imageContainer.getRequestUrl() : null; if (imageContainer != null) { // Cancel previous image request imageContainer.cancelRequest(); imageView.setTag(null); } if (requestUrl != null) { // Queue new request to fetch image imageContainer = set(requestUrl, getImageListener(getResources(), imageView, placeHolder, mFadeInImage), maxWidth, maxHeight, bitmap); // Store request in ImageView tag imageView.setTag(imageContainer); } else { if (!(imageView instanceof PhotoView)) { imageView.setImageDrawable(placeHolder); } imageView.setTag(null); } return imageContainer; } private static ImageListener getImageListener(final Resources resources, final ImageView imageView, final Drawable placeHolder, final boolean fadeInImage) { return new ImageListener() { @Override public void onResponse(ImageContainer response, boolean isImmediate) { imageView.setTag(null); if (response.getBitmap() != null) { if (imageView instanceof PhotoView) { setPhotoImageBitmap((PhotoView) imageView, response.getBitmap(), resources, fadeInImage && !isImmediate); } else { setImageBitmap(imageView, response.getBitmap(), resources, fadeInImage && !isImmediate); } } else { if (!(imageView instanceof PhotoView)) { imageView.setImageDrawable(placeHolder); } } } @Override public void onErrorResponse(VolleyError volleyError) { } }; } private static RequestQueue newRequestQueue(Context context, ImageCacheParams imageCacheParams) { Network network = new BasicNetwork(Utils.hasHoneycomb() ? new HurlStack() : new HttpClientStack(AndroidHttpClient.newInstance(NetUtils.getUserAgent(context)))); Cache cache; if (null != imageCacheParams) { cache = new DiskLruBasedCache(imageCacheParams); } else { cache = new DiskLruBasedCache(Utils.getDiskCacheDir(context, CACHE_DIR)); } RequestQueue queue = new RequestQueue(cache, network); queue.start(); return queue; } /** * Sets a {@link android.graphics.Bitmap} to an {@link android.widget.ImageView} using a * fade-in animation. If there is a {@link android.graphics.drawable.Drawable} already set on * the ImageView then use that as the image to fade from. Otherwise fade in from a transparent * Drawable. */ @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1) private static void setImageBitmap(final ImageView imageView, final BitmapDrawable bitmapDrawable, Resources resources, boolean fadeIn) { // If we're fading in and on HC MR1+ if (fadeIn && Utils.hasHoneycombMR1()) { // Use ViewPropertyAnimator to run a simple fade in + fade out animation to update the // ImageView imageView.animate().scaleY(0.95f).scaleX(0.95f).alpha(0f) .setDuration(imageView.getDrawable() == null ? 0 : HALF_FADE_IN_TIME) .setListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { imageView.setImageDrawable(bitmapDrawable); imageView.animate().alpha(1f).scaleY(1f).scaleX(1f).setDuration(HALF_FADE_IN_TIME) .setListener(null); } }); } else if (fadeIn) { // Otherwise use a TransitionDrawable to fade in Drawable initialDrawable; if (imageView.getDrawable() != null) { initialDrawable = imageView.getDrawable(); } else { initialDrawable = transparentDrawable; } // Use TransitionDrawable to fade in final TransitionDrawable td = new TransitionDrawable( new Drawable[] { initialDrawable, bitmapDrawable }); imageView.setImageDrawable(td); td.startTransition(Utils.ANIMATION_FADE_IN_TIME); } else { // No fade in, just set bitmap directly imageView.setImageDrawable(bitmapDrawable); } } /** * Sets a {@link android.graphics.Bitmap} to an {@link android.widget.ImageView} using a * fade-in animation. If there is a {@link android.graphics.drawable.Drawable} already set on * the ImageView then use that as the image to fade from. Otherwise fade in from a transparent * Drawable. */ @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1) private static void setPhotoImageBitmap(final PhotoView imageView, final BitmapDrawable bitmapDrawable, Resources resources, boolean fadeIn) { // If we're fading in and on HC MR1+ if (fadeIn && Utils.hasHoneycombMR1()) { // Use ViewPropertyAnimator to run a simple fade in + fade out animation to update the // ImageView imageView.animate().scaleY(0.95f).scaleX(0.95f).alpha(0f) .setDuration(imageView.getDrawable() == null ? 0 : HALF_FADE_IN_TIME) .setListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { imageView.bindDrawable(bitmapDrawable); imageView.animate().alpha(1f).scaleY(1f).scaleX(1f).setDuration(HALF_FADE_IN_TIME) .setListener(null); } }); } else if (fadeIn) { // Otherwise use a TransitionDrawable to fade in Drawable initialDrawable; if (imageView.getDrawable() != null) { initialDrawable = imageView.getDrawable(); } else { initialDrawable = transparentDrawable; } // Use TransitionDrawable to fade in final TransitionDrawable td = new TransitionDrawable( new Drawable[] { initialDrawable, bitmapDrawable }); imageView.bindDrawable(td); td.startTransition(Utils.ANIMATION_FADE_IN_TIME); } else { // No fade in, just set bitmap directly imageView.bindDrawable(bitmapDrawable); } } /** * Interface an activity can implement to provide an ImageLoader to its children fragments. */ public interface ImageLoaderProvider { SimpleImageLoader getImageLoaderInstance(); } }