package com.bignerdranch.android.custombehavior; import android.content.Context; import android.support.design.widget.CoordinatorLayout; import android.support.design.widget.FloatingActionButton; import android.support.design.widget.Snackbar; import android.support.v4.view.ViewCompat; import android.util.AttributeSet; import android.view.View; import java.util.List; public class ShrinkBehavior extends CoordinatorLayout.Behavior<FloatingActionButton> { public ShrinkBehavior() { } public ShrinkBehavior(Context context, AttributeSet attrs) { super(context, attrs); } @Override public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) { return dependency instanceof Snackbar.SnackbarLayout; } @Override public boolean onDependentViewChanged(CoordinatorLayout parent, FloatingActionButton child, View dependency) { float translationY = getFabTranslationYForSnackbar(parent, child); float percentComplete = -translationY / dependency.getHeight(); float scaleFactor = 1 - percentComplete; child.setScaleX(scaleFactor); child.setScaleY(scaleFactor); return false; } private float getFabTranslationYForSnackbar(CoordinatorLayout parent, FloatingActionButton fab) { float minOffset = 0; final List<View> dependencies = parent.getDependencies(fab); for (int i = 0, z = dependencies.size(); i < z; i++) { final View view = dependencies.get(i); if (view instanceof Snackbar.SnackbarLayout && parent.doViewsOverlap(fab, view)) { minOffset = Math.min(minOffset, ViewCompat.getTranslationY(view) - view.getHeight()); } } return minOffset; } }