FooterBehavior.java

package org.opensilk.common.ui.behavior;

import android.content.Context;
import android.os.Build;
import android.support.design.widget.CoordinatorLayout;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.ViewPropertyAnimatorListener;
import android.support.v4.view.animation.FastOutSlowInInterpolator;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.view.animation.Interpolator;
import android.widget.LinearLayout;

/**
 * Created by drew on 9/3/15.
 */
public class FooterBehavior extends CoordinatorLayout.Behavior<View> {
    private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
    private boolean mIsAnimatingOut = false;

    public FooterBehavior(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, View child,
                                       View directTargetChild, View target, int nestedScrollAxes) {
        return (nestedScrollAxes & ViewCompat.SCROLL_AXIS_VERTICAL) != 0;
    }

    @Override
    public void onNestedScroll(CoordinatorLayout coordinatorLayout, View child, View target,
                               int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
        if (dyConsumed > 0 && !this.mIsAnimatingOut && child.getVisibility() == View.VISIBLE) {
            animateOut(child);
        } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
            animateIn(child);
        }
    }

    private void animateOut(final View view) {
        ViewCompat.animate(view)
                .translationY(view.getHeight())
                .setInterpolator(INTERPOLATOR)
                .withLayer()
                .setListener(new ViewPropertyAnimatorListener() {
                    public void onAnimationStart(View view) {
                        mIsAnimatingOut = true;
                    }

                    public void onAnimationCancel(View view) {
                        mIsAnimatingOut = false;
                    }

                    public void onAnimationEnd(View view) {
                        mIsAnimatingOut = false;
                        view.setVisibility(View.GONE);
                    }
                })
                .start();
    }

    private void animateIn(final View view) {
        ViewCompat.animate(view)
                .translationY(0)
                .setInterpolator(INTERPOLATOR)
                .withLayer()
                .setListener(new ViewPropertyAnimatorListener() {
                    @Override
                    public void onAnimationStart(View view) {
                        view.setVisibility(View.VISIBLE);
                    }

                    @Override
                    public void onAnimationEnd(View view) {

                    }

                    @Override
                    public void onAnimationCancel(View view) {

                    }
                })
                .start();
    }
}