How to lock Android screen via ADB?

Question

Is there a way to lock the Android screen via the ADB?

I find ways to lock the display in an apk, but I want to lock the screen from the PC via ADB, to simulate a displ

Answer 1

For those using earlier versions of android (4.2+ at least), dumpsys power has a different output.
Instead of using mPowerState= as the answer given by @Jakub Czaplicki, I used mScreenOn=.

p = Runtime.getRuntime().exec("su", null, null);
OutputStream o = p.getOutputStream();
o.write(("dumpsys power").getBytes("ASCII"));
o.flush();
o.close();
p.waitFor();

boolean screenState;
BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((res = in.readLine()) != null) dump += res;
screenState = dump.charAt( dump.indexOf("mScreenOn=") + 10 ) == 't';

screenState is true (screen on), or false (screen off).