当活动onPause（）时显示警报对话框

Question

I am trying to show an alert dialog when a countdown timer finishes and the activity is sent in the background via the onPause() method.

I did some research but couldn't find something to fit my needs.

I tried to achieve this by using a handler:

private Handler myHandler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
                int aResponse = msg.getData().getInt("message");
                if (aResponse == DISPLAY_DLG) {
                    showStopAlarmDialog();
                }
            }
        };

And in the timer's onFinish() method

Message msgObj = myHandler.obtainMessage();
Bundle b = new Bundle();
b.putInt("message", DISPLAY_DLG);
msgObj.setData(b);
myHandler.sendMessage(msgObj);

However, this still only works when the activity is in the front.

Answer 1

I would recommend using the AlarmManager for this task. Otherwise you have to be aware of handling a wake lock so the device doesn't goes to sleep, and if the time to elapse is too long then you will hit unnecessary battery drain.

Using the AlarmManager to fire an Intent and receive it in your app is the way that has work the better for me. Be sure to set the alarm when the activity goes to onPause() and unset the alarm when onResume() . You can also check if launching an Activity with Theme.Dialog is gonna suit better to your needs, 'cause if you lose the activity Context you won't be able to display a regular dialog.

Hope this helps.