com.beesham.beerac.ui.ScrollAwareFABBehavior.java Source code

Introduction

Here is the source code for com.beesham.beerac.ui.ScrollAwareFABBehavior.java

Source

/*
 * Copyright 2015 The Android Open Source Project
 *
 * 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.
 */

package com.beesham.beerac.ui;

import android.content.Context;
import android.content.res.TypedArray;
import android.support.design.widget.AppBarLayout;
import android.support.design.widget.CoordinatorLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.v4.view.animation.FastOutSlowInInterpolator;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Interpolator;

import com.beesham.beerac.R;

/**
 * Created by Beesham on 2/25/2017.
 */

public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
    private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
    private boolean mIsAnimatingOut = false;
    private int toolbarHeight;

    public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
        super();
        this.toolbarHeight = getToolbarHeight(context);
    }

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

    @Override
    public boolean onDependentViewChanged(CoordinatorLayout parent, FloatingActionButton fab, View dependency) {
        if (dependency instanceof AppBarLayout) {
            CoordinatorLayout.LayoutParams lp = (CoordinatorLayout.LayoutParams) fab.getLayoutParams();
            int fabBottomMargin = lp.bottomMargin;
            int distanceToScroll = fab.getHeight() + fabBottomMargin;
            float ratio = (float) dependency.getY() / (float) toolbarHeight;
            fab.setTranslationY(-distanceToScroll * ratio);
        }
        return true;
    }

    public int getToolbarHeight(Context context) {
        final TypedArray styledAttributes = context.getTheme()
                .obtainStyledAttributes(new int[] { R.attr.actionBarSize });
        int toolbarHeight = (int) styledAttributes.getDimension(0, 0);
        styledAttributes.recycle();

        return toolbarHeight;
    }

}