@Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                // Navigate "up" the demo structure to the launchpad activity.
                // See http://developer.android.com/design/patterns/navigation.html for more.
                NavUtils.navigateUpTo(this, new Intent(this, AnimationsDemo.class));
                return true;

            case R.id.action_toggle:
                // Toggle whether content is loaded.
                mContentLoaded = !mContentLoaded;
                showContentOrLoadingIndicator(mContentLoaded);
                return true;
        }

        return super.onOptionsItemSelected(item);
    }
The system "short" animation time duration, in milliseconds. This duration is ideal for
subtle animations or animations that occur very frequently.
app/src/main/java/home/smart/fly/animations/ui/activity/demos/CrossfadeActivity.java