如何显示警报不同的活动 [英] How to display an alert to a different activity

问题描述

我有一个活动，第二个活动。在第二个活动，我需要关闭的活动和的然后的第一活动再次显示警报给用户返回。

I have an activity and a second activity. In the second activity, I need to close the activity and then display an alert to the user back in the first activity again.

下面是当前code我使用弹出警报，并关闭活动：

Here is the current code I use to bring up the alert and close the activity:

String message = "message";

AlertDialog alertDialog = new AlertDialog.Builder(SecondActivity.this).create();
alertDialog.setMessage(message);
alertDialog.show();

alertDialog.setOnDismissListener(new OnDismissListener() 
{
    public void onDismiss(final DialogInterface dialog) 
    {
        finish();
    }
});

所以，我怎样才能让这个第二活性完成，再一次回到了第一个活动，显示一个警告用户？

So how can I make it so that the second activity finishes, and then once back on the first activity, display an alert to the user?

我想这个问题，以及：

String message = "message";

finish();

AlertDialog alertDialog = new AlertDialog.Builder(FirstActivity.class).create();
alertDialog.setMessage(message);
alertDialog.show();

但我得到这个错误：

but I get this error:

构造AlertDialog.Builder（类＆LT; FirstActivity＆gt;）的未定义

推荐答案

我需要使用 startActivityForResult 方法来启动从第一个第二个活动，然后通过在结果到第一个活动从次活动。

I needed to start the second activity from the first one by using the startActivityForResult method, and then pass the result to the first activity from the second activity.

Intent data = new Intent(); 
data.putExtra("reference for the message", message); // give the intent the String value to be passed to other activity
setResult(Activity.RESULT_OK, data);

finish();

在顶部将这个第一个活动课：

public static final int REQ_SECOND_ACTIVITY = 100;

这是如何启动次活动从第一个活动：

startActivityForResult(new Intent(FirstActivity.this, SecondActivity.class), REQ_SECOND_ACTIVITY);

最后，此方法添加到您的第一个活动课：

// this method gets called when the second activity is closed
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (resultCode == RESULT_OK && requestCode == REQ_SECOND_ACTIVITY) 
    {   
        String message = data.getStringExtra("reference for the message");

        AlertDialog alertDialog = new AlertDialog.Builder(FirstActivity.this).create();
        alertDialog.setMessage(message);
        alertDialog.show();        
    }
}

这个方法放在一起组合从用户 beworker 在这个问题上和的letroll~~MD~~aux 的过那个<一href="http://stackoverflow.com/questions/920306/sending-data-back-to-the-main-activity-in-android">question.

This method was put together in combination from users beworker on this question and letroll over at that question.

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