Lock/unlock android phone programatically

Lock and unlock phone in android programmatically/ Lock phone using power manager/wave lock in android/Turn screen off in android/Display screen off in android

To turn screen on in android, use the code below

powermanager=  ((PowerManager)context.getSystemService(Context.POWER_SERVICE));

                 wakeLock=powermanager.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP, "tag");

            wakeLock.acquire();

To lock or to turn off display screen off, use the code below

if(wakeLock.isHeld())

            {

                  wakeLock.release();

            }

Also set permission in Android manifest file

<uses-permission android:name="android.permission.WAKE_LOCK"/>