Turn on/off Android device

Question

I want to implement some code lines that allow Android turn on/off screen like we quick turn on/off device by using Power button. Is there any way to do that?

The exactly what i want is recall LockScreen display. After turn screen off -> turn it on -> the LockScreen will be displayed. Do you have any suggestion? — Nguyen, Dec 13 '12 at 02:54

score 2 · Accepted Answer · edited May 23 '17 at 10:33

2

It seems you want to lock the device not turn it off. To lock the device its a simple code. Mentioned here

It uses device Policy Manager lockNow() method

In case of a RuntimeError use the method described in this question to set permissions

Android DevicePolicyManager lockNow()

http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html

To switch off the device:

This is not possible but you can reboot it using PowerManager

http://developer.android.com/reference/android/os/PowerManager.html#reboot

Note this requires REBOOT permission and OS may cancel it.

edited May 23 '17 at 10:33

Community

1
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answered Dec 13 '12 at 02:48

cjds

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I am working on Android framework, so maybe there are some differences bwt application and framework. It still doesn't work. Anyway, thanks for your reply – Nguyen Dec 14 '12 at 09:18

score 2 · Answer 2 · answered Dec 13 '12 at 02:49

2

You can use DevicePolicyManger.lockNow(): http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#lockNow%28%29

answered Dec 13 '12 at 02:49

Josh

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After call lockNow(), it throw exception:E/AndroidRuntime( 1159): *** FATAL EXCEPTION IN SYSTEM PROCESS: WindowManagerPolicy E/AndroidRuntime( 1159): java.lang.NullPointerException – Nguyen Dec 13 '12 at 03:22
after that, the device is forced to reboot – Nguyen Dec 13 '12 at 03:24

score 0 · Answer 3 · answered Aug 28 '16 at 17:52

Yes, you can do with programming using below code, Note: This solution works only on rooted device

Shutdown:

try {
    Process proc = Runtime.getRuntime()
                    .exec(new String[]{ "su", "-c", "reboot -p" });
    proc.waitFor();
} catch (Exception ex) {
    ex.printStackTrace();
}

Restart:

Same code, just use "reboot" instead of "reboot -p".

Turn on/off Android device

3 Answers3