异步加载图片
1第一步在getview中：
String videoUrl =ltVideos.get(position).getPath();
Bitmap cachedImage = asyncIThumbnailLoader.loadCacheThumbnail(videoUrl);
if(cachedImage!=null)
{
img.setBackgroundDrawable(null);
img.setImageBitmap(cachedImage);
}
else //没找到缓存设置默认图片
{
//Log.d("sky","cachedImagefalse");
img.setBackgroundDrawable(null);
img.setImageResource(R.drawable.default_poster);
}
在asyncIThumbnailLoader中
/**
* 检查缓存中的图片
* containsKey() 方法来检测是否数据是否存在,在同步情况下,可以大大降低消耗.
*/
public synchronized Bitmap loadCacheThumbnail(finalString imageUrl)
{
if(imageCache.containsKey(imageUrl))
{
Bitmap bitmap = imageCache.get(imageUrl); //缓存中有的话，直接去取
return bitmap;
}
return null;
}
2//在onCreate 建立U盘插入广播，在onReceive中，建立线程
private void setSDCardReceiver(){
broadcastRec= new BroadcastReceiver() {
public void onReceive(Context context,Intent intent) {
if(Intent.ACTION_MEDIA_REMOVED.equals(intent.getAction())
||Intent.ACTION_MEDIA_UNMOUNTED.equals(intent.getAction())
|| Intent.ACTION_MEDIA_BAD_REMOVAL.equals(intent.getAction())
||Constants.ACTION_NEWPVR_TSFILE.equals(intent.getAction()))
{
private void localKillGetThumbnailThread()
{
if(localGetThumbnailThreadRunable!=null)
{
localGetThumbnailThreadRunable.stop();
}
}
private void localCreateGetThumbnailThread()
{
localKillGetThumbnailThread();
localGetThumbnailThreadRunable = newLocalGetThumbnailThreadRunable();
newThread(localGetThumbnailThreadRunable).start();
}
}
3,线程的run方法中
private class LocalGetThumbnailThreadRunableimplements Runnable{
privateboolean stopFlag = false;
publicvoid stop()
{
stopFlag= true;
}
publicvoid run()
{
booleannRet;
if(visualVideoCount == 0)
{
visualVideoCount= 18;
}
endVideoPos= startVideoPos + visualVideoCount;
if(endVideoPos > gvVideo.getCount())
{
endVideoPos= gvVideo.getCount();
}
if(ltVideos == null||ltVideos.size()==0)
{
return;
}
//从一个位置处开始加载。。。
for(inti= startVideoPos;i<endVideoPos;i++)
{
if(stopFlag)
{
break;
}
try
{
StringvideoUrl = ltVideos.get(i).getPath();
BitmapcachedImage = asyncIThumbnailLoader.loadCacheThumbnail(videoUrl);
if(cachedImage==null)//缓存中没有的话
{
StringvideoId=""+ltVideos.get(i).getId();
cachedImage= adGvVideo.loadNoCacheThumbnailForAdapter(MainVideoPage.this,videoUrl,videoId);
if(cachedImage == null)
{
nRet= adGvVideo.loadNoCacheThumbnailBlockingForAdapter(MainVideoPage.this,videoUrl,videoId);
}
else
{
}
}
if(cachedImage==null)
{
Log.d("sky","cachedImageis null");
}
myHandler.post(newRunnable() {
publicvoid run() {
try
{
adGvVideo.notifyDataSetChanged();
}
catch(Exceptione)
{
e.printStackTrace();
}
}
});
}
catch(Exception e)
{
e.printStackTrace();
}
} // end for
}
}
loadNoCacheThumbnailForAdapter函数和loadNoCacheThumbnailBlockingForAdapter：
public synchronized boolean loadNoCacheThumbnailBlockingForAdapter(finalActivity context,final String Url, final String videos_id)
{
returnasyncIThumbnailLoader.loadNoCacheThumbnailBlocking(context,Url,videos_id);
}
publicsynchronized Bitmap loadNoCacheThumbnailForAdapter(finalActivity context,final String Url, final String videos_id)
{
returnasyncIThumbnailLoader.loadNoCacheThumbnail(context,Url,videos_id);
}
public Bitmap loadNoCacheThumbnail(final Activity context,finalString Url, final String videos_id)
{
//msgObj obj = new msgObj();
//obj.imageUrl = Url;
//obj.imageBmp =loadThumbnailFromDCIM(context,videos_id);
Bitmap imageBmp = loadThumbnailFromDCIM(context,videos_id);
if(imageBmp!=null)
{
//从消息池里返回一个新的Message，比new一个新的消息更高效
//Message message =imageLoadhandler.obtainMessage(0, obj);
//imageLoadhandler.sendMessage(message);
imageCache.put(Url,imageBmp);
}
return imageBmp;
}
public static Bitmap loadThumbnailFromDCIM(Activitycontext,String videos_id) {
Bitmap bitmap = null;
ContentResolverresolver=context.getContentResolver();
CursorthumbCursor=resolver.query(MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI,
newString[]{"video_id","_data"}, null, null, null);
////thumbCursor.getString(1)*/
if(thumbCursor != null)
{
while(thumbCursor.moveToNext())
{
inttempid = thumbCursor.getInt(0);
Stringsid = ""+tempid;
if(sid.equals(videos_id))
{
bitmap= BitmapFactory.decodeFile(thumbCursor.getString(1));
break;
}
}
}
if(thumbCursor != null)
{
thumbCursor.close();
}
return bitmap; }
public staticBitmap loadThumbnailFromMediastoreBlocking(Activitycontext,String videos_id) {
Bitmap bitmap = null;
Uri baseUri =MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI;
ContentResolvercr=context.getContentResolver();
String[] PROJECTION = new String[]{"video_id","_data"};
//阻塞方式获取thumbnail blocking
Uri blockingUri =baseUri.buildUpon().appendQueryParameter("blocking", "1")
.appendQueryParameter("orig_id",String.valueOf(videos_id))
.appendQueryParameter("group_id",String.valueOf(MediaStore.Video.Thumbnails.MINI_KIND)).build();
CursorthumbCursor=cr.query(blockingUri, PROJECTION, null, null, null);
////thumbCursor.getString(1)*/
if(thumbCursor != null)
{
while(thumbCursor.moveToNext())
{
inttempid = thumbCursor.getInt(0);
Stringsid = ""+tempid;
if(sid.equals(videos_id))
{
//vm.setThumbnailPath(thumbCursor.getString(1));
bitmap=MediaStore.Video.Thumbnails.getThumbnail(context.getContentResolver(),tempid,
MediaStore.Video.Thumbnails.MINI_KIND,null); //Log.i("loadThumbnailFromMediastore","******thumbnailPath3333333333333="+thumbCursor.getString(1));
break;
}
}
}
if(thumbCursor!= null)
{
thumbCursor.close();
}
return bitmap;
}