CODEWITHSUNDEEP
javaandroidmultithreadingperformanceandroid-handler
falvojr
falvojr

Reputation: 3080

Communicating with the UI Thread Android: User Inactivity

I have a Android application that verifies the user inactivity through a Handler. But I would like know if my Handler implementation is the best solution in my case.

The code:

public abstract class UserInteractionControlActivity extends Activity {

    private static final int SESSION_TIME_OUT = 300000;
    private static final int SESSION_DELAY_TIME = 60000;

    private final Handler mHandler = new Handler(Looper.getMainLooper());

    private long mLastUserInterationTime;

    protected void onResume() {
        super.onResume();
        mHandler.postDelayed(new UserInteractionControl(), SESSION_TIME_OUT);
        Log.i("LOG_KEY", "HANDLER FIRST POST!");
    }

    public void onUserInteraction() {
        super.onUserInteraction();
        mLastUserInterationTime = System.currentTimeMillis();
    }

    private final class UserInteractionControl implements Runnable {

        public void run() {
            long currentTime = System.currentTimeMillis();
            long inactiveTime = currentTime - mLastUserInterationTime;
            if (inactiveTime > SESSION_TIME_OUT) {
                Log.i("LOG_KEY", "TIME OUT!");
            } else {
                mHandler.postDelayed(new UserInteractionControl(), SESSION_DELAY_TIME);
                Log.i("LOG_KEY", "HANDLER POST AGAIN!");
            }
        }
    }
}

My main questions are:

1) What is the difference between instantiate Handler using new Handler(Looper.getMainLooper()) and getWindow().getDecorView().getHandler()?

2) The use of System.currentTimeMillis() in this context is secure?

Upvotes: 3

Views: 572

Answers (1)

Kevin Coppock
Kevin Coppock

Reputation: 134664

1) As @corsair992 said, they should be equivalent, however I think having your own instance of Handler is preferable, as you explicitly control it. If you need to remove any pending Runnable instances later, you can just do a removeCallbacksAndRunnables(null); to remove any messages that your Handler has posted without affecting the decor view's Handler.

2) Don't use System.currentTimeMillis(). SystemClock.elapsedRealtime() is a much better indicator of elapsed time, as it won't be affected by the user changing the Date/Time (whereas currentTimeMillis() does change).

Upvotes: 3

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