转载自： http://doinone.iteye.com/blog/1074283
Android中获取网络图片是一件耗时的操作，如果直接获取有可能会出现应用程序无响应（ANR:Application Not Responding）对话框的情况。对于这种情况，一般的方法就是耗时操作用线程来实现。下面列三种获取url图片的方法：
1.直接获取：（容易：ANR，不建议）
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- mImageView = (ImageView)this.findViewById(R.id.imageThreadConcept) ;
- Drawable drawable = loadImageFromNetwork(IMAGE_URL);
- mImageView.setImageDrawable(drawable) ;
公用方法：
[java] view plain copy
- private Drawable loadImageFromNetwork(String imageUrl)
- {
- Drawable drawable = null;
- try {
- // 可以在这里通过文件名来判断，是否本地有此图片
- drawable = Drawable.createFromStream(
- new URL(imageUrl).openStream(), "image.jpg");
- } catch (IOException e) {
- Log.d("test", e.getMessage());
- }
- if (drawable == null) {
- Log.d("test", "null drawable");
- } else {
- Log.d("test", "not null drawable");
- }
- return drawable ;
- }
2. 后台线程获取url图片：
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- mImageView = (ImageView)this.findViewById(R.id.imageThreadConcept) ;
- new Thread(new Runnable(){
- Drawable drawable = loadImageFromNetwork(IMAGE_URL);
- @Override
- public void run() {
- // post() 特别关键，就是到UI主线程去更新图片
- mImageView.post(new Runnable(){
- @Override
- public void run() {
- // TODO Auto-generated method stub
- mImageView.setImageDrawable(drawable) ;
- }}) ;
- }
- }).start() ;
3.AsyncTask获取url图片
[java] view plain copy
- mImageView = (ImageView)this.findViewById(R.id.imageThreadConcept) ;
- new DownloadImageTask().execute(IMAGE_URL) ;
- private class DownloadImageTask extends AsyncTask<String, Void, Drawable>
- {
- protected Drawable doInBackground(String... urls) {
- return loadImageFromNetwork(urls[0]);
- }
- protected void onPostExecute(Drawable result) {
- mImageView.setImageDrawable(result);
- }
- }