Suggestion: handle onOffsetChanged better

[AndroidDeveloperLB]

It seems it won't show the title&subtitle if the toolbar is currently showing them, after orientation change.

I suggest to make it much shorter, and ditch the field used for it:

@Override
public void onOffsetChanged(AppBarLayout appBarLayout, int offset) {
    int maxScroll = appBarLayout.getTotalScrollRange();
    float percentage = (float) Math.abs(offset) / (float) maxScroll;
    toolbarHeaderView.setVisibility(percentage < 1f ? View.GONE : View.VISIBLE);
}