如何阻止我的警报对话框立即被关闭？

Question

I'm trying to read a boarding pass barcode to inform the user if we have details on their flight and if so why not. I'm using AlertDialogs to communicate with the user as Toast notifications did not appear clearly enough. However they dismiss as soon as they are called without the user clicking ok.

How do I stop this? Is onActivityResult the wrong place to put this code?

public void onActivityResult(int requestCode, int resultCode, Intent intent) {
    if (requestCode == 0) {
        if (resultCode == RESULT_OK) {
            String boardingPassString = intent
                    .getStringExtra("SCAN_RESULT");
            Log.d("Scan Result", "contents: " + boardingPassString);
            String flightNumber = dataProcessor.decodeFlightNumber(boardingPassString);

            Builder dialogBuilder = new AlertDialog.Builder(this);
            String isFlightOld = isFlightOld(boardingPassString);
            if(isFlightOld.equals(CURRENT))
            {
                Log.d("Block", "Current");
                postData(flightNumber);
            }
            else if(isFlightOld.equals(TOO_NEW))
            {
                dialogBuilder.setTitle(R.string.dialog_title_new);

                dialogBuilder.setMessage(R.string.dialog_msg_new1 + flightNumber + R.string.dialog_msg_new2);
                dialogBuilder.setPositiveButton(android.R.string.ok, null);
                AlertDialog alert = dialogBuilder.create();
                alert.show();

                Log.d("Block", getResources().getString(R.string.dialog_title_new));
            }
            else if(isFlightOld.equals(OLD))
            {
                dialogBuilder.setTitle(R.string.dialog_title_old);
                dialogBuilder.setMessage(R.string.dialog_msg_old1 + flightNumber + R.string.dialog_msg_old2);
                dialogBuilder.setPositiveButton(android.R.string.ok, null);
                AlertDialog alert = dialogBuilder.create();
                alert.show();
                Log.d("Block", getResources().getString(R.string.dialog_title_old));
            }
            else
            {
                dialogBuilder.setTitle(R.string.dialog_title_error);
                dialogBuilder.setMessage(R.string.dialog_msg_error).show();
                dialogBuilder.setPositiveButton(android.R.string.ok, null);
                AlertDialog alert = dialogBuilder.create();
                alert.show();
                Log.d("Block", getResources().getString(R.string.dialog_title_error));
            }


        } else if (resultCode == RESULT_CANCELED) {
            Log.d("Scan Result", "RESULT_CANCELED");
        }
    }
}

Calling Code

scanButton.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {

            // Testing shortcut
            // =================================
            // getXMLFlightDetails("US729");
            // ==================================

            // Uncomment to return Barcode scanning!!!
            // =============================================
            Intent intent = new Intent(getApplicationContext(),
                    CaptureActivity.class);
            intent.setAction("com.google.zxing.client.android.SCAN");
            intent.putExtra("SCAN_MODE", "PDF417_MODE");
            intent.putExtra("SAVE_HISTORY", false);
            startActivityForResult(intent, 0);

        }
    });

Answer 1

Just try the following code, hopefully it should work. You need to pass the context in Dialog Builder. Then the Android OS will know which activity the dialog is attached to and where it should be popped.

public void onActivityResult(int requestCode, int resultCode, Intent intent) {
    if (requestCode == 0) {
        if (resultCode == RESULT_OK) {
            String boardingPassString = intent
                    .getStringExtra("SCAN_RESULT");
            Log.d("Scan Result", "contents: " + boardingPassString);
            String flightNumber = dataProcessor.decodeFlightNumber(boardingPassString);

        Builder dialogBuilder = new AlertDialog.Builder(this);
        String isFlightOld = isFlightOld(boardingPassString);
        if(isFlightOld.equals(CURRENT))
        {
            Log.d("Block", "Current");
            postData(flightNumber);
        }
        else if(isFlightOld.equals(TOO_NEW))
        {
            displayAlert(R.string.dialog_msg_new1 + flightNumber + R.string.dialog_msg_new2);
            Log.d("Block", getResources().getString(R.string.dialog_title_new));
        }
        else if(isFlightOld.equals(OLD))
        {
            displayAlert(R.string.dialog_msg_old1 + flightNumber + R.string.dialog_msg_old2);
            Log.d("Block", getResources().getString(R.string.dialog_title_old));
        }
        else
        {
            displayAlert(R.string.dialog_msg_error);
            Log.d("Block", getResources().getString(R.string.dialog_title_error));
        }


    } else if (resultCode == RESULT_CANCELED) {
        Log.d("Scan Result", "RESULT_CANCELED");
    }
}
}



displayAlert(String message)
{

  AlertDialog.Builder alertDialog = new AlertDialog.Builder(MyActivity.this);
  alertDialog.setTitle(getResources().getString(R.string.alert_title));
  alertDialog.setMessage(message);

  alertDialog.setPositiveButton(getResources().getString(R.string.ok),
    new DialogInterface.OnClickListener() {
      public void onClick(DialogInterface dialog, int which) 
      {
         //your action here
      }
  });


  alertDialog.setNegativeButton(getResources().getString(R.string.ok),
      new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int which) {
           // Your Action here      
      }
  });
  alertDialog.show();

}

If this does not solve your problem. Then you need to show ur entire activity code, as it may be possible that your activity is getting finished soon after the dialog is displayed to the screen.

Answer 2

This turned out to be a multi-threading issue. The method postData used a HTTPResponse call so was not on the main thread. This method would finish a few milliseconds after tyhe dialog had been displayed and was what was dismissing the alertDialogs.

A simple join() call to get the main thread to wait for the postData method to do it's buisness before displaying the alertDialogs was all it took.