How to lock/unlock phone programmatically : Android

on BroadcastReceiver set up the wakelock and in the activity

Do This:

Window window = this.getWindow();
window.addFlags(LayoutParams.FLAG_DISMISS_KEYGUARD);
window.addFlags(LayoutParams.FLAG_SHOW_WHEN_LOCKED);
window.addFlags(LayoutParams.FLAG_TURN_SCREEN_ON);

import following

import android.view.Window;
import android.view.WindowManager.LayoutParams;

As of API 27, FLAG_SHOW_WHEN_LOCKED and FLAG_TURN_SCREEN_ON were deprecated. Instead use this in the Manifest

<activity
    android:name=".MyActivity"
    android:turnScreenOn="true"
    android:showWhenLocked="true"/>

Or, for general usage, in your activity:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
        setTurnScreenOn(true);
        setShowWhenLocked(true);
    } else {
        Window window = getWindow();
        window.addFlags(LayoutParams.FLAG_SHOW_WHEN_LOCKED);
        window.addFlags(LayoutParams.FLAG_TURN_SCREEN_ON);
    }
}