MainContainerBehaviour.java

package com.patloew.countries.ui.main;

import android.content.Context;
import android.support.design.widget.AppBarLayout;
import android.support.design.widget.CoordinatorLayout;
import android.util.AttributeSet;
import android.view.View;

/* Copyright 2016 Patrick Löwenstein
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License. */
public class MainContainerBehaviour extends CoordinatorLayout.Behavior<View> {

    public MainContainerBehaviour(Context context, AttributeSet attrs) {}

    @Override
    public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {
        return dependency instanceof AppBarLayout;
    }

    @Override
    public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {
        CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) child.getLayoutParams();

        if(dependency instanceof AppBarLayout) {
            layoutParams.topMargin = dependency.getMeasuredHeight();
            child.setLayoutParams(layoutParams);
        }

        return true;
    }

}