Android應用程序在等待HTTP響應時顯示黑屏

Question

我一直在試圖開發一個Android應用程序，它可以讓用戶拍照並通過HTTP發送圖像。我正在使用本機相機。

用戶拍攝照片並點擊保存按鈕後，當應用程序發送信息並等待響應時，屏幕出現黑屏。我寧願顯示一個進度對話框，但無論我嘗試了什麼，黑屏都停留在那裏，進度對話框只有在獲得響應並點擊後退按鈕後才能看到。我曾嘗試使用setContentView（）無濟於事。這些線程用於HTTP請求。

下面是攝像頭的開始和結束的代碼：

protected void startCameraActivity() 
{ 

    File file = new File(_path); 
    Uri out = Uri.fromFile(file); 

    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); 
    intent.putExtra(MediaStore.EXTRA_OUTPUT, out); 

    startActivityForResult(intent, 0); 
} 

protected void onActivityResult(int requestCode, int resultCode, Intent data) 
{ 
    switch(resultCode) 
    { 
    case 0: 
     break; 

    case -1: 
     m_ProgressDialog = ProgressDialog.show(MainActivity.this, "Please wait...", "Uploading data ...", true, true); 
     onPhoto(); 
     break; 
    } 
} 

protected void onPhoto() 
{ 
    taken = true; 


    PipedOutputStream pos = new PipedOutputStream(); 
    PipedInputStream pis = null; 
    try { 
     pis = new PipedInputStream(pos); 
    } catch (IOException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 
    Sender sender = new Sender(pos); 
    Receiver receiver = new Receiver(pis); 
    sender.start(); 
    receiver.start(); 
    try { 
     sender.join(); 
     receiver.join(); 
     try { 
      field.setText(receiver.getIn().readUTF()); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } catch (InterruptedException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 

    try { 
     pis.close(); 
     pos.close(); 
    } catch (IOException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 

} 

Answer 1

退房此鏈接：How can I use an Async Task to upload a file to the server?

在onPreExecute()你可以定義你想顯示什麼，而圖像處理（進度酒吧，一個微調......）。

Answer 2

可以使用的AsyncTask，並顯示ProgressDialog任務的同時執行

private class YourTask extends AsyncTask { 
     private ProgressDialog dialog; 

     private GetNewsTask(Context context) { 
      this.dialog = new ProgressDialog(context); 
     } 

     @Override 
     protected void onPreExecute() { 
      this.dialog.setMessage(getResources().getString(R.string.loading)); 
      this.dialog.show(); 
     } 

     @Override 
     protected Object doInBackground(Object... objects) { 
      // your hard work 
      return something; 
     } 

     @Override 
     protected void onPostExecute(Object result) { 
      if (this.dialog.isShowing()) this.dialog.dismiss(); 
      // hanle results 

     } 

    }