Android Widget 中ListView加載網絡圖片

關於Widget的介紹和用法能夠看這兩篇博文，寫的很是詳細了

Android 之窗口小部件詳解--App Widget http://www.cnblogs.com/skywang12345/p/3158310.html 

Android 之窗口小部件高級篇--App Widget 之 RemoteViews http://www.cnblogs.com/skywang12345/p/3264991.html

上面兩篇博文沒有提到怎麼給Widget中的ListView或者GridView中顯示網絡圖片，而咱們的項目的需求中須要Widget中的ListView填充接口得到的文字和圖片，試過不少方法最後發現仍是如下這種僞同步比較讓人滿意。

private Map<Integer, Boolean> flags = Collections.synchronizedMap(new HashMap<Integer, Boolean>());
            private Bitmap mBitmap;
            private Handler handler = new Handler(Looper.getMainLooper());


            @Override
            public RemoteViews getViewAt(final int position) { 
                //這裏初始化RemoteView，設置監聽，等等....

                flags.put(position, false);
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        //這裏用了ImageLoader，或者別的帶有加載回調加載庫
                        ImageLoader.getInstance().loadImage(datas.get(position).getImgUrl, new SimpleImageLoadingListener() {
                            @Override
                            public void onLoadingStarted(String imageUri, View view) {
                            }
    
                            @Override
                            public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
                                flags.put(position, true);
                            }
    
                            @Override
                            public void onLoadingCancelled(String imageUri, View view) {
                                flags.put(position, true);
                            }
    
                            @Override
                            public void onLoadingComplete(String arg0, View arg1, Bitmap bitmap) {
                                mBitmap = bitmap;
                                flags.put(position, true);
                            }
                        });
                    }
                });
                //在此一直等待獲取到網絡圖片
                while (!flags.get(position)) {
                    try {
                        Thread.sleep(2000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                flags.put(position, false);
                if (mBitmap != null) {
                    mRemoteViews.setImageViewBitmap(R.id.widget_item_image, mBitmap);
                } else {
                    mRemoteViews.setImageViewResource(R.id.widget_item_image, R.mipmap.ic_launcher);
                }
                mBitmap = null;
    
                return mRemoteViews;
            }