Keep the screen on while the activity is visible.

KeepScreenOn.java

public class KeepScreenOn extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_keepscreenon);
    }

    @Override
    protected void onResume() {
        super.onResume();
        this.getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    }

    @Override
    protected void onPause() {
        this.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
        super.onPause();
    }
}