Collapsing Toolbar only for one Fragment in Navigation View

Question

The Problem

I have a navigation drawer with different fragments. There is a default toolbar every Fragment should use, except of one Fragment

Answer 1

The best solution that I found to easily collapse, lock it(keep it in collapsed mode) and unlock the collapsingToolbar.

private void collapseAppBar() {
    // Collapse the AppBarLayout with animation
    mAppBarLayout.setExpanded(false, true);
}

private void lockAppBar() {
    /* Disable the nestedScrolling to disable expanding the
     appBar with dragging the nestedScrollView below it */
    ViewCompat.setNestedScrollingEnabled(nestedScrollView, false);

    /* But still appBar is expandable with dragging the appBar itself
    and below code disables that too
     */
    CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) mAppBarLayout.getLayoutParams();
    AppBarLayout.Behavior behavior = (AppBarLayout.Behavior) params.getBehavior();
    behavior.setDragCallback(new AppBarLayout.Behavior.DragCallback() {
        @Override
        public boolean canDrag(AppBarLayout appBarLayout) {
            return false;
        }
    });
}

private void unLockAppBar() {
    ViewCompat.setNestedScrollingEnabled(nestedScrollView, true);

    CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) mAppBarLayout.getLayoutParams();
    AppBarLayout.Behavior behavior = (AppBarLayout.Behavior) params.getBehavior();
    if (behavior != null) {
        behavior.setDragCallback(new AppBarLayout.Behavior.DragCallback() {
            @Override
            public boolean canDrag(AppBarLayout appBarLayout) {
                return true;
            }
        });
    }
}

And I use these functions in this way:

    Fragment fragment = null;
    Class fragmentClass;
    switch (menuItem.getItemId()) {
        case R.id.fragment1:
            unLockAppBar();
            fragmentClass = first_Fragment.class;
            break;
        case R.id.fragment2:
            collapseAppBar();
            lockAppBar();
            fragmentClass = second_Fragment.class;
            break;
        case R.id.fragment3:
            collapseAppBar();
            lockAppBar();
            fragmentClass = third_Fragment.class;
            break;