《Afinal 开源框架》FinalBitmap 之 简单配置与加载原理

这一节主要看看FinalBitmap的配置，它主要有哪些参数需要配置，并引出display方法

FinalBitmap finalBitmap;
                finalBitmap = FinalBitmap.create(this);
                finalBitmap.configBitmapLoadThreadSize(3);
                //图片大小
                finalBitmap.configBitmapMaxHeight(800);
                finalBitmap.configBitmapMaxWidth(480);
                //磁盘缓存路径
                finalBitmap.configDiskCachePath("");
                finalBitmap.configDiskCacheSize(10*1024);
                //配置显示
                finalBitmap.configDisplayer(new  Displayer() {
                         
                        @Override
                        public void loadFailDisplay(View imageView, Bitmap bitmap) {
                                // TODO Auto-generated method stub
                                //设置失败 显示图片 404 等等
                        }
                         
                        @Override
                        public void loadCompletedisplay(View imageView, Bitmap bitmap,
                                        BitmapDisplayConfig config) {
                                // TODO Auto-generated method stub
                                // 加载成功  开启动画等等imageView.startAnimation();
                        }
                });
                 
                //可自己定义下载器
                finalBitmap.configDownlader(new Downloader() {
                         
                        @Override
                        public byte[] download(String urlString) {
                                // TODO Auto-generated method stub
                                //自己写下载代码。这个已经是异步操作了
                                return null;
                        }
                });
                 
                //加载时显示的图片。即默认图片
                finalBitmap.configLoadingImage(null);
                 
                //配置内存缓存大小
                finalBitmap.configMemoryCacheSize(4);
                 
                //待我后面再讲
                finalBitmap.configRecycleImmediately(true);
                finalBitmap.setExitTasksEarly(true);
                 
                 
                //开始加载,如果你实例化后直接调用此方法，上面配置参数都默认的
                finalBitmap.display(imageView, "http://www.baidu.com/pic/logo.gif");

我们直接进入display方法

public void display(View imageView,String uri){
                doDisplay(imageView,uri,null);
        }

private void doDisplay(View imageView, String uri, BitmapDisplayConfig displayConfig) {
                if(!mInit ){
                        init();//用来建立缓存路径 ：1.内存 2磁盘 3.实例化线程池。如果我们没有在上面配置，就会加载默认配置
                }
                 
                if (TextUtils.isEmpty(uri) || imageView == null) {//判断uri地址
                        return;
                }
                 
                if(displayConfig == null)
                        displayConfig = mConfig.defaultDisplayConfig;
         
                Bitmap bitmap = null;
         
                if (mImageCache != null) {//判断是否在缓存中
                        bitmap = mImageCache.getBitmapFromMemoryCache(uri);
                }
         
                if (bitmap != null) {//如果存在，直接加载
                        if(imageView instanceof ImageView){
                                ((ImageView)imageView).setImageBitmap(bitmap);
                        }else{
                                imageView.setBackgroundDrawable(new BitmapDrawable(bitmap));
                        }
                         
                         
                }else if (checkImageTask(uri, imageView)) {//检测该任务是否已经运行了
                        final BitmapLoadAndDisplayTask task = new BitmapLoadAndDisplayTask(imageView, displayConfig );
                        //自定义Drawable ，设置默认图片
                        final AsyncDrawable asyncDrawable = new AsyncDrawable(mContext.getResources(), displayConfig.getLoadingBitmap(), task);
                
                        if(imageView instanceof ImageView){
                                ((ImageView)imageView).setImageDrawable(asyncDrawable);
                        }else{
                                imageView.setBackgroundDrawable(asyncDrawable);
                        }
                 
                task.executeOnExecutor(bitmapLoadAndDisplayExecutor, uri);//执行加载任务
            }
        }
大家看看任务线程

/**
         * bitmap下载显示的线程
         * @author michael yang
         */
        private class BitmapLoadAndDisplayTask extends AsyncTask<Object, Void, Bitmap> {
                private Object data;
                private final WeakReference<View> imageViewReference;
                private final BitmapDisplayConfig displayConfig;
 
                public BitmapLoadAndDisplayTask(View imageView,BitmapDisplayConfig config) {
                        imageViewReference = new WeakReference<View>(imageView);
                        displayConfig = config;
                }
 
                @Override
                protected Bitmap doInBackground(Object... params) {
                        data = params[0];
                        final String dataString = String.valueOf(data);
                        Bitmap bitmap = null;
 
                        synchronized (mPauseWorkLock) {
                                while (mPauseWork && !isCancelled()) {
                                        try {
                                                mPauseWorkLock.wait();
                                        } catch (InterruptedException e) {
                                        }
                                }
                        }
 
                        if (bitmap == null && !isCancelled()&& getAttachedImageView() != null && !mExitTasksEarly) {
                                bitmap = processBitmap(dataString,displayConfig);//下载数据
                        }
                         
                        if(bitmap!=null){
                                mImageCache.addToMemoryCache(dataString, bitmap);//下载完成后加入缓存
                        }
 
                        return bitmap;
                }
 
                @Override
                protected void onPostExecute(Bitmap bitmap) {
                        if (isCancelled() || mExitTasksEarly) {
                                bitmap = null;
                        }
 
                        // 判断线程和当前的imageview是否是匹配
                        final View imageView = getAttachedImageView();
                        if (bitmap != null && imageView != null) {//显示数据
                                mConfig.displayer.loadCompletedisplay(imageView,bitmap,displayConfig);                        
                        }else if(bitmap == null && imageView!=null ){
                                mConfig.displayer.loadFailDisplay(imageView, displayConfig.getLoadfailBitmap());
                        }
                }
 
                @Override
                protected void onCancelled(Bitmap bitmap) {
                        super.onCancelled(bitmap);
                        synchronized (mPauseWorkLock) {
                                mPauseWorkLock.notifyAll();
                        }
                }
 
                /**
                 * 获取线程匹配的imageView,防止出现闪动的现象
                 * @return
                 */
                private View getAttachedImageView() {
                        final View imageView = imageViewReference.get();
                        final BitmapLoadAndDisplayTask bitmapWorkerTask = getBitmapTaskFromImageView(imageView);
 
                        if (this == bitmapWorkerTask) {
                                return imageView;
                        }
 
                        return null;
                }
        }