抓取遠程圖像Asynchrounously一個ImageAdapter

Question

我有一個Android圖庫ImageAdapter實施getView（）（如下所示）：

public View getView(int arg0, View arg1, ViewGroup arg2) { 
    String strURL = "http://app1.exactdev.co.za/android/celebs/celeb" + (arg0+1) + ".jpg";  
    Bitmap bm = RemoteBitMapHelper.getRemoteBitMap(strURL); //synchronous request    

    ImageView i = new ImageView(ctx);  
    i.setImageBitmap(bm); 
    return i; 
} 

我怎樣才能讓getView完成自己的工作異步？

Answer 1

簡單的答案是你可以把它放在一個AsyncTask中。像下面這樣（未經測試）

public View getView(int arg0, View arg1, ViewGroup arg2) { 

    final ImageView i = new ImageView(ctx); 
    String url = "http://app1.exactdev.co.za/android/celebs/celeb" + (arg0 + 1) + ".jpg"; 

    new AsyncTask<String, Void, Bitmap>() { 

     @Override 
     protected Bitmap doInBackground(String... urls) { 
      return RemoteBitMapHelper.getRemoteBitMap(urls[0]); 
     } 

     @Override 
     protected void onPostExecute(Bitmap result) { 
      if (result != null) { 
       i.setImageBitmap(result); 
      } 
     } 

    }.execute(url); 

    return i; 
}