横版布局的RecyclerView的回弹效果实现

横版布局的RecyclerView的回弹效果实现

直接上代码：

package com.ahtelit.zbv.myapplication;

import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.TranslateAnimation;
import android.widget.HorizontalScrollView;

/**
 * Created by Administrator on 2018/5/16.
 * qzx
 */

public class MyHorizontalScrollView extends HorizontalScrollView{

    private View inner;

    public MyHorizontalScrollView(Context context) {
        this(context,null);
    }

    public MyHorizontalScrollView(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }

    public MyHorizontalScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        //取消滑动到最前和最后是出现的蓝色颜色阴影块
        setOverScrollMode(View.OVER_SCROLL_NEVER);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        if(getChildCount()>0)
        inner=getChildAt(0);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if(inner!=null){
            commOnTouchEvent(ev);
        }
        return super.onTouchEvent(ev);
    }

    private float downX;
    private static final int DEFAULT_DEVIDE=4;
    private Rect normal = new Rect();
    private void commOnTouchEvent(MotionEvent ev){
        switch (ev.getAction()){
            case MotionEvent.ACTION_DOWN:
                downX=ev.getX();
                break;
            case MotionEvent.ACTION_MOVE:
                float moveX=ev.getX();
                int deltX=(int)(downX-moveX)/DEFAULT_DEVIDE;
                downX=moveX;

                //不能滚动就直接移动布局
                if(isNeedMove()){
                    if (normal.isEmpty()) {
                        // 保存正常的布局位置
                        normal.set(inner.getLeft(), inner.getTop(),
                                inner.getRight(), inner.getBottom());
                        return;
                    }
                    inner.layout(inner.getLeft()-deltX,inner.getTop(),inner.getRight()-deltX,inner.getBottom());
                }
                break;
            case MotionEvent.ACTION_UP:
                if (isNeedAnimation()) {
                    // Log.v("mlguitar", "will up and animation");
                    animation();
                }
                break;
        }
    }

    private boolean isNeedMove(){
        int offset=inner.getMeasuredWidth()-getWidth();
        int scrollX=getScrollX();
        Log.d("zbv","offset="+offset+";scrollX="+scrollX);
        //头和尾
        if(scrollX==0||scrollX==offset){
            return true;
        }
        return false;
    }

    // 开启动画移动

    public void animation() {
        // 开启移动动画
        TranslateAnimation ta = new TranslateAnimation(getLeft(), normal.left, 0,
                0);
        ta.setDuration(200);
        inner.startAnimation(ta);
        // 设置回到正常的布局位置
        inner.layout(normal.left, normal.top, normal.right, normal.bottom);
        normal.setEmpty();
    }

    // 是否需要开启动画
    public boolean isNeedAnimation() {
        return !normal.isEmpty();
    }
}

使用如下（我这里让scrollview设置背景色，这样的话移动recyclerview的话也就是同样的颜色了，具体recyclerview这个的代码就不贴了）：

<com.ahtelit.zbv.myapplication.MyHorizontalScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#555555"
        >

        <android.support.v7.widget.RecyclerView
            android:paddingBottom="15dp"
            android:paddingTop="15dp"

            android:id="@+id/rv_thumbnail"
            android:layout_alignParentBottom="true"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"> 
         </android.support.v7.widget.RecyclerView>
  </com.ahtelit.zbv.myapplication.MyHorizontalScrollView>