@Override
public void onScroll(int l, int t, int oldl, int oldt) {
int height = mHeader.getMeasuredHeight() - mToolbar.getMeasuredHeight();
Drawable drawable = mToolbarContainer.getBackground();
int alpha = 255 * (Math.min(Math.max(t, 0), height)) / height;
drawable.setAlpha(alpha);
if (alpha >= 255) {
ViewCompat.setElevation(mToolbarContainer, mElevation);
ViewCompat.setElevation(mHeader, 0);
} else {
ViewCompat.setElevation(mToolbarContainer, 0);
ViewCompat.setElevation(mHeader, mElevation);
}
}
