AndroidUI系列--在DecorView层解决RecyclerView和ScrollView的滑动冲突

Posted 2022-12-10 SingleShu888

滑动冲突，这个是作安卓的必经之坑。最开始的ListView和ScollView冲突，或者ListView嵌套ListView滑动冲突，再或者ListView和ViewPager的滑动冲突，再或者是GraidView等可滑动控件互相嵌套的冲突。解决方案呢，有很多。比如在onTouchEvent中拦截事件。又或者自定义ListView，修改onMesure测量，使它在测量时获得最大的宽高，这样可以让它不滑动。全部展示，当然作为在android摸爬滚打了这么久的程序猿，这些坑都应该踩过了，而且网上一大堆解决方案，不得不说，这就是开源的好处啊，想着谷歌巴巴把kotlin扶上位了，我们这些苦逼的程序猿，那就只有跟着大部队走了。没办法呀~夹缝里生存。

View的绘制流程，Activity–phonewindow–decorview–contentview，如下图

我们平时在Activity的setContentView就是在ContentViews作文章。那么我们的冲突就是在这里，在ContentView里设置了一个activity_main.xml,为什么会有滑动冲突呢，那是因为recyclerview和scollview都设置在了activity_main.xml。那么换个角度，如果把recyclerview加在contentviews和activity_main.xml布局平级。那么是不是就不存在滑动冲突了呢，想到就来试试。
首先自定义一个view，用来弹窗。

package com.example.administrator.bounceview;

import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.View;

/**
 * Created by ShuWen on 2017/5/23.
 */

public class BounceView extends View 

    private int mArcMaxHeight;//弹窗最高距离
    private int mArcHeight;//记录变换过程的距离
    private Paint mPaint;//画笔
    private Path mPath = new Path();//绘制动画弧度
    private BounceAnimatorListener animatorListener;//动画开始的监听回调
    private Status status = Status.NONE;//记录动画的状态


    public enum Status
        //没动，上升，下降
        NONE,STATUS_UP,STATUS_DOWN
    

    public BounceView(Context context) 
        super(context);
        init();
    


    public BounceView(Context context, AttributeSet attrs) 
        super(context, attrs);
        init();
    

    public BounceView(Context context, AttributeSet attrs, int defStyleAttr) 
        super(context, attrs, defStyleAttr);
        init();
    

    //初始化
    private void init() 
        mPaint = new Paint();
        mPaint.setColor(Color.WHITE);
        mPaint.setAntiAlias(true);
        mPaint.setStyle(Paint.Style.FILL);

        mArcMaxHeight = getResources().getDimensionPixelOffset(R.dimen.m_maxarcheight);

    

    //上升的动画
    public void show()
        status = Status.STATUS_UP;
        if (animatorListener != null)
            this.postDelayed(new Runnable() 
                @Override
                public void run() 
                   animatorListener.showContent();
                
            ,600);
        
        ValueAnimator animator = ValueAnimator.ofInt(0,mArcMaxHeight);
        animator.setDuration(700);
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() 
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) 
                mArcHeight = (int) valueAnimator.getAnimatedValue();
                if (mArcHeight == mArcMaxHeight)
                    bounce();
                
                invalidate();
            
        );
        animator.start();
    

    //下降的动画
    private void bounce() 
        status = Status.STATUS_DOWN;
        ValueAnimator valueAnimator = ValueAnimator.ofInt(mArcMaxHeight,0);
        valueAnimator.setDuration(600);
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() 
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) 
                mArcHeight = (int) valueAnimator.getAnimatedValue();
                invalidate();
            
        );
        valueAnimator.start();
    

    @Override
    protected void onDraw(Canvas canvas) 
        super.onDraw(canvas);
        int currentY = 0;
        switch (status)
            case NONE:
                currentY = 0;
                break;
            case STATUS_UP:
                currentY = (int) (getHeight()*(1 - (float)(mArcHeight/mArcMaxHeight))+mArcMaxHeight);
                break;
            case STATUS_DOWN:
                currentY = mArcMaxHeight;
                break;
        

        mPath.reset();
        mPath.moveTo(0,currentY);
        mPath.quadTo(getWidth()/2,currentY - mArcHeight,getWidth(),currentY);
        mPath.lineTo(getWidth(),getHeight());
        mPath.lineTo(0,getHeight());
        mPath.close();

        canvas.drawPath(mPath,mPaint);

    

    public void setAnimatorListener(BounceAnimatorListener animatorListener)
        this.animatorListener = animatorListener;
    

    public interface BounceAnimatorListener
        void showContent();
    

上升过程中，绘制动画，使用ValueAnimator在回调里进行更新界面，调用invalidate()。中间使用到了二阶贝塞尔曲线，关于贝塞尔其实很简单的，在网上一搜，当然就有了。

那么在创建一个类，用来加载BounceVeiw。

package com.example.administrator.bounceview;

import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.widget.FrameLayout;

/**
 * Created by ShuWen on 2017/5/23.
 */

public class BounceMenu 
    private RecyclerView recyclerView;
    private BounceView bounceView;
    private ViewGroup parentVG;
    private View rootView;

    private BounceMenu(View view, int resId, final MyAdapter myAdapter) 
        parentVG = findParentVG(view);

        rootView = LayoutInflater.from(view.getContext()).inflate(resId,null,false);
        recyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerview);
        bounceView = (BounceView) rootView.findViewById(R.id.bounceview);

        recyclerView.setLayoutManager(new LinearLayoutManager(view.getContext()));
        bounceView.setAnimatorListener(new BounceView.BounceAnimatorListener() 
            @Override
            public void showContent() 
                recyclerView.setVisibility(View.VISIBLE);
                recyclerView.setAdapter(myAdapter);
                recyclerView.scheduleLayoutAnimation();
            
        );
    

    public static BounceMenu makeBounce(View view, int resId, final MyAdapter myAdapter)
        return new BounceMenu(view, resId, myAdapter);
    

    public void show()
        if (rootView != null)
            parentVG.removeView(rootView);
        
        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        parentVG.addView(rootView,layoutParams);
        bounceView.show();
    

    private ViewGroup findParentVG(View view) 
        do 
            if (view instanceof FrameLayout)
                //找到decorview的根布局
                if (view.getId() == android.R.id.content)
                    return (ViewGroup) view;
                
            

            if (view != null)
                ViewParent viewParent = view.getParent();
                view = viewParent instanceof View? (View) viewParent :null;
            
        while (view!= null);
        return null;
    

在这里面，传入需要添加recylerview的跟布局，通过这个根布局获得decorview的contentviews这个布局，然后在这个布局上添加recyclerview。这样就是与activity_main同级，不会有滑动冲突。在bounceview的监听里，添加recyclerview的动画。
那么再来看看MianAcicity的代码：

package com.example.administrator.bounceview;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity 

    private MyAdapter myAdapter;
    private List<String> stringList;

    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        stringList = new ArrayList<>();

        for (int i = 0; i < 20; i++) 
            stringList.add("阿西吧"+i);
        

        myAdapter = new MyAdapter(this,stringList) 
            @Override
            protected int ItemLayoutId() 
                return R.layout.item;
            

            @Override
            protected void onBindHolder(MyViewHolder myViewHolder, int position) 
                TextView textView = myViewHolder.getTextView(R.id.text);
                textView.setText(stringList.get(position));
            

        ;

    

    public void click(View view)
        BounceMenu bounceMenu = BounceMenu.makeBounce(findViewById(R.id.activity_main),R.layout.bounce_view_layout,myAdapter);
        bounceMenu.show();
    

调用就是相当的简单了。同时还有炫酷的动画，何乐而不为呢。接下来所有代码都贴出来。
activity_main的xml布局。使用ScrollView，展示主要数据。在每一项的点击事件，触发弹窗，recyclerview。

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.administrator.bounceview.MainActivity">

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#465">
        <LinearLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:gravity="center"
                android:textSize="20sp"
                android:onClick="click"
                android:text="你滑动啊"
                />
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#fff">
            </View>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:gravity="center"
                android:textSize="20sp"
                android:onClick="click"
                android:text="你滑动啊"
                />
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#fff">
            </View>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:gravity="center"
                android:onClick="click"
                android:textSize="20sp"
                android:text="你滑动啊"
                />
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#fff">
            </View>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:gravity="center"
                android:textSize="20sp"
                android:onClick="click"
                android:text="你滑动啊"
                />
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#fff">
            </View>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:gravity="center"
                android:textSize="20sp"
                android:onClick="click"
                android:text="你滑动啊"
                />
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#fff">
            </View>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:gravity="center"
                android:textSize="20sp"
                android:onClick="click"
                android:text="你滑动啊"
                />
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#fff">
            </View>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:gravity="center"
                android:textSize="20sp"
                android:onClick="click"
                android:text="你滑动啊"
                />
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#fff">
            </View> <TextView
            android:layout_width="match_parent"
            android:layout_height="100dp"
            android:gravity="center"
            android:textSize="20sp"
            android:onClick="click"
            android:text="你滑动啊"
            />
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#fff">
            </View>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="100dp"
                android:gravity="center"
                android:textSize="20sp"
                android:onClick="click"
                android:text="你滑动啊"
                />
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#fff">
            </View>

        </LinearLayout>
    </ScrollView>

</RelativeLayout>

那么再看看弹窗的xml。

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="290dp"
        android:layout_gravity="bottom">

        <com.example.administrator.bounceview.BounceView
            android:id="@+id/bounceview"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            />

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recyclerview"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipChildren="false"
            android:overScrollMode="never"
            android:layout_alignParentBottom="true"
            android:layoutAnimation="@anim/bounce_layout"
            android:layout_marginTop="70dp">

        </android.support.v7.widget.RecyclerView>
    </RelativeLayout>

</FrameLayout>

这里就是弹窗了，recyclerview和scrollview同级，不会产生滑动冲突。
这个是解决滑动冲突的一个可行方案，相当不错。如果觉得动画不必要，直接去掉动画，只需要BounceMenu中的一些逻辑就ok了。我会把代码放在git上，有兴趣的朋友可以自己研究研究。

git地址：https://github.com/SingleShu/BounceView

效果图：