scheduleVisibilityCheck - A method to place a runnable on a handlers message queue

VisibilityTracker.java

public class VisibilityTracker {
    private static final long VISIBILITY_CHECK_DELAY_MILLIS = 100;
    private WeakHashMap<View, TrackingInfo> mTrackedViews = new WeakHashMap<>();
    private ViewTreeObserver.OnPreDrawListener mOnPreDrawListener;
    private VisibilityTrackerListener mVisibilityTrackerListener;
    private boolean mIsVisibilityCheckedScheduled;
    private Handler mVisibilityHandler;
    private VisibilityChecker mVisibilityChecker;
    private Runnable mVisibilityRunnable;

public VisibilityTracker(Activity activity) {
    View rootView = activity.getWindow().getDecorView();

    mVisibilityHandler = new Handler();
    mVisibilityChecker = new VisibilityChecker();
    mVisibilityRunnable = new VisibilityRunnable();
    // ........


private void scheduleVisibilityCheck() {
    if (mIsVisibilityCheckedScheduled) {
        return;
    }
    mIsVisibilityCheckedScheduled = true;
    mVisibilityHandler.postDelayed(mVisibilityRunnable, VISIBILITY_CHECK_DELAY_MILLIS);
}