Android在进入睡眠状态时会更改活动

Question

I'm maintaining an Android app that controls an industrial process. It has a main Activity/screen which allows you to selects various industrial tasks, and each task has its own activity/screen.

The problem - if the user is in one of these other Activities and the droid goes to sleep (say because the worker takes a break or goes to lunch), when it wakes up again it's back in the main Activity!

This is hard to debug because to debug it I have to be connected to the USB and when it's attached to USB it doesn't go to sleep.

1. What Activity Lifecycle events are associated with it going to sleep? What does it actually mean to go to sleep - the display goes off but obviously other stuff is happening, too, because when it wakes up it's in a different activity.

2. Is there a way I can allow it to enter sleep mode even when attached to USB so I can set breakpoints and debug this properly?

Details:

• Samsung Galaxy Player (basically Samsung phone without the phone) running 2.35.
• Activity that's open when it goes to sleep uses the default Standard launch mode.

Answer 1

When android goes to sleep, the top most activity receives onPause , but it still remains as the top most activity in the activity stack, and therefore it will receive onResume and will be started when the device awakes.

The reason you see your main activity when the device wakes up is that there should be some code in your onPause which forces the top most activity to finish after onPause (similarly there might be some settings. For example, setting noHistory to true in AndroidManifest.xml for an activity forces the activity to shutdown itself when it receives onPause, and so when you go back, you will see Main Activity on top).