使用異步Http客戶端庫下載圖像

Question

我試圖使用AsyncHttpClient library by loopj從URL下載圖像資源，我不知道爲什麼我無法將其保存到內部存儲。我的問題是我沒有看到內部存儲器上運行下面的代碼中的任何圖像文件，但我沒有看到日誌或編譯時的任何錯誤。以下Toast聲明均適用。這是我正在使用的代碼。我是新的在stackoverflow，所以請裸露在我身邊。

代碼：

String[] allowedTypes = new String[] { "image/png" }; 
    AsyncHttpClient client = new AsyncHttpClient(); 
    client.get("http://example.com/dock.png", 
      new BinaryHttpResponseHandler(allowedTypes) { 
       @Override 
       public void onSuccess(int i, Header[] headers, byte[] bytes) { 

        Toast.makeText(getApplicationContext(),"Successful in finding file",Toast.LENGTH_SHORT).show(); 
        try { 
         Toast.makeText(getApplicationContext(),"Success",Toast.LENGTH_SHORT).show(); 
         FileOutputStream f = new FileOutputStream((new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES) + File.separator + "imgdwo.png"))); 
         f.write(bytes); //your bytes 
         f.close(); 
        } catch (FileNotFoundException e) { 
         e.printStackTrace(); 
        } catch (IOException e) { 
         e.printStackTrace(); 
        } 
       } 

       @Override 
       public void onFailure(int i, Header[] headers, byte[] bytes, Throwable throwable) { 

       } 


    }); 

更新：我在內部存儲器改變了硬編碼的位置，但不解決問題。該logcat的低於：

java.io.FileNotFoundException: /storage/emulated/0/Pictures: open failed: EISDIR (Is a directory) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at libcore.io.IoBridge.open(IoBridge.java:416) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at java.io.FileOutputStream.<init>(FileOutputStream.java:88) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at java.io.FileOutputStream.<init>(FileOutputStream.java:128) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at java.io.FileOutputStream.<init>(FileOutputStream.java:117) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at com.example.abhishek.asynchttpclient.AsyncActivity$1.onSuccess(AsyncActivity.java:41) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at com.loopj.android.http.AsyncHttpResponseHandler.handleMessage(AsyncHttpResponseHandler.java:311) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at com.loopj.android.http.AsyncHttpResponseHandler$ResponderHandler.handleMessage(AsyncHttpResponseHandler.java:138) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:99) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at android.os.Looper.loop(Looper.java:137) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5293) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:511) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at dalvik.system.NativeStart.main(Native Method) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ Caused by: libcore.io.ErrnoException: open failed: EISDIR (Is a directory) 
06-29 09:07:28.721 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at libcore.io.Posix.open(Native Method) 
06-29 09:07:28.726 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110) 
06-29 09:07:28.726 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ at libcore.io.IoBridge.open(IoBridge.java:400) 
06-29 09:07:28.726 17675-17675/com.example.abhishek.asynchttpclient W/System.err﹕ ... 14 more 

Answer 1

點要注意的，

1. 你必須確保，存在與之前已經存在相同名稱的目錄。嘗試在創建FileOutputStream之前刪除該目錄。

2. 使用new FileAsyncHttpResponseHandler(Context)構造函數，它會自動在您的應用程序的緩存目錄中創建臨時文件，然後您可以移動文件，重命名它，修改其內容或刪除它。

Answer 2

使用此代碼創建目錄如果不存在並在創建文件之後。

     Bitmap mIcon; 
         File dir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES); 
if (!dir.exists()) { 
        //noinspection ResultOfMethodCallIgnored 
        dir.mkdir(); 
       } 
String fname = "myimage.png"; 
File myimage = new File(dir, fname); 
         try { 
         InputStream in = new java.net.URL(imageurl).openStream(); 
         mIcon = BitmapFactory.decodeStream(in); 

         try { 
          FileOutputStream out = new FileOutputStream(myimage); 
          mIcon.compress(
            Bitmap.CompressFormat.JPEG, 
            100, out); 
          out.flush(); 
          out.close(); 
          return myimage; 

         } catch (FileNotFoundException e) { 
          return null; 
         } catch (IOException e) { 
          return null; 
         } 

        } catch (Exception e) { 
         return null; 
        } 

該代碼下載映像並將其保存在您想要的目錄和名稱中。使用它並分享任何錯誤。