code: public void setKeyguardLocked(boolean isKeyguardLocked) {
      this.isKeyguardLocked = isKeyguardLocked;
      if (callback != null) {
        if (isKeyguardLocked) {
          callback.onDismissCancelled();
        } else {
          callback.onDismissSucceeded();
        }
        callback = null;
      }
    }
docs: Sets whether the device keyguard is locked or not. This affects the value to be returned by
  {@link #isKeyguardLocked()} and also invokes callbacks set in
  {@link KeyguardManager#requestDismissKeyguard()}.
  
  @param isKeyguardLocked true to lock the keyguard. If a KeyguardDismissCallback is set will
  fire {@link KeyguardDismissCallback#onDismissCancelled()} or false to unlock and dismiss the
  keyguard firing {@link KeyguardDismissCallback#onDismissSucceeded()} if a
  KeyguardDismissCallback is set.