FooterBehaviorDependAppBar.java

package io.github.mayubao.kuaichuan.ui.view;

import android.animation.Animator;
import android.content.Context;
import android.support.design.widget.CoordinatorLayout;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.animation.FastOutSlowInInterpolator;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewPropertyAnimator;
import android.view.animation.Interpolator;

/**
 * 测试Behavior的类
 *
 * Created by mayubao on 2016/12/6.
 * Contact me 345269374@qq.com
 */
public class FooterBehaviorDependAppBar extends CoordinatorLayout.Behavior<View>{

    private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
    private static final String TAG = FooterBehaviorDependAppBar.class.getSimpleName();


    private int sinceDirectionChange;

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

    //1.判断滑动的方向 我们需要垂直滑动
    @Override
    public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, View child, View directTargetChild, View target, int nestedScrollAxes) {
        Log.i(TAG, "onStartNestedScroll------>>>nestedScrollAxes : " +  nestedScrollAxes);
        Log.i(TAG, "onStartNestedScroll------>>>directTargetChild : " +  directTargetChild.getClass().getSimpleName());
        Log.i(TAG, "onStartNestedScroll------>>>target : " +  target.getClass().getSimpleName());
        return (nestedScrollAxes & ViewCompat.SCROLL_AXIS_VERTICAL) != 0;
    }

    //2.根据滑动的距离显示和隐藏footer view
    @Override
    public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, View child, View target, int dx, int dy, int[] consumed) {
        Log.i(TAG, "onNestedPreScroll------>>>" + "dx:" + dx + ",dy:" + dy);
        Log.i(TAG, "onNestedPreScroll------>>>target : " +  target.getClass().getSimpleName());

        if (dy > 0 && sinceDirectionChange < 0 || dy < 0 && sinceDirectionChange > 0) {
            child.animate().cancel();
            sinceDirectionChange = 0;
        }
        sinceDirectionChange += dy;
        if (sinceDirectionChange > child.getHeight() && child.getVisibility() == View.VISIBLE) {
            hide(child);
        } else if (sinceDirectionChange < 0 && child.getVisibility() == View.GONE) {
            show(child);
        }
    }


    private void hide(final View view) {
        ViewPropertyAnimator animator = view.animate().translationY(view.getHeight()).setInterpolator(INTERPOLATOR).setDuration(200);
        animator.setListener(new Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animator) {

            }

            @Override
            public void onAnimationEnd(Animator animator) {
                view.setVisibility(View.GONE);
            }

            @Override
            public void onAnimationCancel(Animator animator) {
                show(view);
            }

            @Override
            public void onAnimationRepeat(Animator animator) {

            }
        });
        animator.start();
    }


    private void show(final View view) {
        ViewPropertyAnimator animator = view.animate().translationY(0).setInterpolator(INTERPOLATOR).setDuration(200);
        animator.setListener(new Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animator) {

            }

            @Override
            public void onAnimationEnd(Animator animator) {
                view.setVisibility(View.VISIBLE);
            }

            @Override
            public void onAnimationCancel(Animator animator) {
                hide(view);
            }

            @Override
            public void onAnimationRepeat(Animator animator) {

            }
        });
        animator.start();

    }
}