Android实现RecyclerView下拉刷新效果

程序员文章站 2022-10-29 15:50:44

本文为大家分享了android实现recyclerview下拉刷新效果的具体代码，供大家参考，具体内容如下思路 realpullrefreshview继承了一...

本文为大家分享了android实现recyclerview下拉刷新效果的具体代码，供大家参考，具体内容如下

思路

realpullrefreshview继承了一个linearlayout
里面放置了一个刷新头布局，将其margin_top设置为负的刷新头的高度的
再添加一个recyclerview
触摸事件分发机制，当在特定条件下让realpullrefreshview拦截触摸事件，否则的话，不拦截，让recyclerview自己去处理触摸事件
在手指下拉时，定义好不同的状态state,在不同状态下，处理不同的显示，这里讲不同状态下的刷新头如何显示，抽象为一个接口，用户可以实现这个接口，自定义刷新头的布局和动画
加载更多的功能是利用recyclerview的多type布局实现的
难点在于触摸事件的拦截，和认真处理各种滑动的问题

使用

xml

 <com.example.apple.quickdemo.realview.view.realpullrefreshview
    android:id="@+id/real_pull_refresh_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    app:refresh_header_view="@layout/headerview"/>

这是headerview

<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
       android:layout_width="match_parent"
       android:layout_height="50dp"
       android:background="#ff0"
       android:orientation="horizontal"
       android:gravity="center">


  <textview
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:background="@color/coloraccent"
    android:visibility="visible"
    android:id="@+id/tv"
    android:gravity="center"
    android:text="下拉刷新"
    android:textsize="21sp"/>
  <imageview
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"

    android:src="@mipmap/ic_launcher"
    android:id="@+id/iv"
    />

</linearlayout>

代码

mrealpullrefreshview.setlayoutmanager(mlayoutmanager);
    mrealpullrefreshview.setadapter(mmyadapte);
    //用户可以自定义自己的刷新头布局和动画
   //mrealpullrefreshview.setonpullshowviewlistener(new gifonpullshowviewlisterner(mrealpullrefreshview));

    mrealpullrefreshview.setonpulllistener(new realpullrefreshview.onpulllistener() {
      @override
      public void onrefresh() {

        mhandler.postdelayed(new runnable() {
          @override
          public void run() {
            mbodies.add(0, new body("新数据"+i++,100));
            mrealpullrefreshview.refreshfinish();
          }
        }, 3000);

      }

      @override
      public void onloadmore() {

        final list<body> more=new arraylist<body>();
        mhandler.postdelayed(new runnable() {
          @override
          public void run() {
            for (int i = 0; i < 3; i++) {
              more.add(new body("more+++"+i,100));

            }


            mbodies.addall(more);
            mrealpullrefreshview.loadmrefinish();
          }
        }, 1500);

      }
    });

自定义刷新头布局和动画

package com.example.apple.quickdemo.realview.show;

import android.animation.objectanimator;
import android.animation.valueanimator;
import android.util.log;
import android.view.view;
import android.widget.imageview;
import android.widget.textview;

import com.example.apple.quickdemo.r;
import com.example.apple.quickdemo.realview.view.realpullrefreshview;

/**
 * created by apple on 2017/7/9.
 */

public class implonpullshowviewlistener implements realpullrefreshview.onpullshowviewlistener {

  private textview mtv;
  private imageview miv;
  private objectanimator mani;
  view mheaderview;


  public implonpullshowviewlistener(realpullrefreshview realpullrefreshview) {
    mheaderview = realpullrefreshview.getrefreshheaderview();
    mtv = (textview) mheaderview.findviewbyid(r.id.tv);
    miv = (imageview) mheaderview.findviewbyid(r.id.iv);
    mani = objectanimator.offloat(miv, "rotation", -15, 15).setduration(300);
    mani.setrepeatcount(valueanimator.infinite);
    mani.setrepeatmode(valueanimator.reverse);
  }

  @override
  public void onpulldownrefreshstate(int scrolly, int headviewheight,int deltay) {
    mtv.settext("下拉刷新");
    float f = -((float) scrolly / (float) headviewheight);
    log.e("tag", f+ "");
    log.e("tag", -scrolly + "scrolly");


    miv.setscalex(f);
    miv.setscaley(f);
  }

  @override
  public void onreleaserefreshstate(int scrolly, int deltay) {
    mtv.settext("松手刷新");

  }

  @override
  public void onrefreshingstate() {
    mtv.settext("正在刷新");
    miv.setscalex(1.0f);
    miv.setscaley(1.0f);
    mani.start();

  }

  @override
  public void ondefaultstate() {
    if (mani.isrunning()){
      mani.end();
      miv.setrotation(0);
    }
  }

}

源码

package com.example.apple.quickdemo.realview.view;

import android.content.context;
import android.content.res.typedarray;
import android.support.annotation.nullable;
import android.support.v7.widget.gridlayoutmanager;
import android.support.v7.widget.linearlayoutmanager;
import android.support.v7.widget.recyclerview;
import android.support.v7.widget.staggeredgridlayoutmanager;
import android.util.attributeset;
import android.util.log;
import android.view.layoutinflater;
import android.view.motionevent;
import android.view.velocitytracker;
import android.view.view;
import android.view.viewgroup;
import android.widget.linearlayout;
import android.widget.scroller;
import android.widget.toast;

import com.example.apple.quickdemo.r;
import com.example.apple.quickdemo.realview.show.implonpullshowviewlistener;

import static android.content.contentvalues.tag;

/**
 * created by apple on 2017/7/7.
 * 下拉刷新
 */

public class realpullrefreshview extends linearlayout {


  private int mtouchslop;
  //  分别记录上次滑动的坐标
  private int mlastx = 0;
  private int mlasty = 0;

  //  分别记录上次滑动的坐标(onintercepttouchenvent)
  private int mlastxintercept = 0;
  private int mlastyintercept = 0;

  private scroller mscroller;
  private velocitytracker mvelocitytracker;


  private recyclerview.adapter madapter;

  public recyclerview getrecyclerview() {
    return mrecyclerview;
  }

  private recyclerview mrecyclerview;


  private int default = 0;
  private final int pull_down_refresh = 1;
  private final int release_refresh = 2;
  private final int refreshing = 3;
  private final int load_more = 4;
  private int state = default;


  private int rfreshheaderwidth;
  private int refreshheadviewheight;


  private onpulllistener monpulllistener;
  private view mrefreshheaderview;

  private recyclerview.layoutmanager mlayoutmanager;


  int refreshheadviewid;

  public void setlayoutmanager(recyclerview.layoutmanager manager) {
    this.mlayoutmanager = manager;
    mrecyclerview.setlayoutmanager(mlayoutmanager);

  }

  public void setadapter(recyclerview.adapter adapter) {
    this.madapter = adapter;
    mrecyclerview.setadapter(madapter);

  }

  public view getrefreshheaderview() {
    return mrefreshheaderview;
  }

  public void setonpullshowviewlistener(onpullshowviewlistener onpullshowviewlistener) {
    monpullshowviewlistener = onpullshowviewlistener;
  }

  private onpullshowviewlistener monpullshowviewlistener;

  public void setonpulllistener(onpulllistener onpulllistener) {
    monpulllistener = onpulllistener;
  }

  public realpullrefreshview(context context) {
    super(context);

    initview(context);

  }

  public realpullrefreshview(context context, @nullable attributeset attrs) {
    super(context, attrs);

    initattrs(context, attrs);
//   ★★★★★一个坑initattrs方法里的typedarray去获取属性时，第一次获取的属性全是0，他会马上重走一次构造方法，再次获取一次，才能获得正确的值
//   如果第一次获取的值为0，则不去initview
    if (refreshheadviewid != 0) {
      initview(context);
    }


  }


  public realpullrefreshview(context context, @nullable attributeset attrs, int defstyleattr) {
    super(context, attrs, defstyleattr);

    initattrs(context, attrs);
    if (refreshheadviewid != 0) {
      initview(context);
    }
  }

  private void initattrs(context context, attributeset attrs) {

    typedarray typedarray = context.obtainstyledattributes(attrs, r.styleable.realpullrefreshview);

    try {

      refreshheadviewid = typedarray.getresourceid(r.styleable.realpullrefreshview_refresh_header_view, 0);


    } finally {
      typedarray.recycle();

    }


  }


  private void initview(context context) {

    mscroller = new scroller(getcontext());
    mvelocitytracker = velocitytracker.obtain();


//    添加headerview

//    ★ ★ ★ ★ ★ 注意不要用这个方法inflate布局，会导致layout的所有属性失效，height、width、margin
//    原因见 http://blog.csdn.net/zhaokaiqiang1992/article/details/36006467
//    ★ ★ ★ ★ ★ mrefreshheaderview = minflater.inflate(r.layout.headerview, null);

    mrefreshheaderview = layoutinflater.from(context).inflate(refreshheadviewid, this, false);
    addview(mrefreshheaderview);
//    }

//    以下代码主要是为了设置头布局的margintop值为-headerviewheight
//    注意必须等到一小会才会得到正确的头布局宽高
    postdelayed(new runnable() {
      @override
      public void run() {
        log.e("q11", refreshheadviewheight + "qqqqqqqqqq   " + mrefreshheaderview.getheight());
        rfreshheaderwidth = mrefreshheaderview.getwidth();
        refreshheadviewheight = mrefreshheaderview.getheight();

        marginlayoutparams lp = new linearlayout.layoutparams(rfreshheaderwidth, refreshheadviewheight);
        lp.setmargins(0, -refreshheadviewheight, 0, 0);
        mrefreshheaderview.setlayoutparams(lp);

      }
    }, 100);


//   添加recyclerview
    mrecyclerview = new recyclerview(context);
    addview(mrecyclerview, layoutparams.match_parent, viewgroup.layoutparams.match_parent);


//   这里我提供了一个默认的显示效果，如果用户不使用mrealpullrefreshview.setonpullshowviewlistener的话，会默认使用这个
//   用户可以实现onpullshowviewlistener接口，去实现自己想要的显示效果
    monpullshowviewlistener = new implonpullshowviewlistener(this);


    setloadmore();


  }

  private void setloadmore() {
    // 当目前的可见条目是所有数据的最后一个时，开始加载新的数据

    mrecyclerview.addonscrolllistener(new recyclerview.onscrolllistener() {

      @override
      public void onscrolled(recyclerview recyclerview, int dx, int dy) {
        super.onscrolled(recyclerview, dx, dy);

        int lastcompletelyvisibleitemposition = -1;
        if (mlayoutmanager instanceof linearlayoutmanager) {
          linearlayoutmanager manager = (linearlayoutmanager) mlayoutmanager;
          lastcompletelyvisibleitemposition = manager.findlastvisibleitemposition();

        } else if (mlayoutmanager instanceof gridlayoutmanager) {
          gridlayoutmanager manager = (gridlayoutmanager) mlayoutmanager;
          lastcompletelyvisibleitemposition = manager.findlastvisibleitemposition();

        } else if (mlayoutmanager instanceof staggeredgridlayoutmanager) {
          staggeredgridlayoutmanager manager = (staggeredgridlayoutmanager) mlayoutmanager;
          lastcompletelyvisibleitemposition = manager.findlastvisibleitempositions(new int[manager.getspancount()])[0];
        }
        if (lastcompletelyvisibleitemposition + 1 == madapter.getitemcount()) {
          if (monpulllistener != null && state == default) {
            state = load_more;
            monpulllistener.onloadmore();
          }
        }


      }
    });
  }


  @override
  public boolean onintercepttouchevent(motionevent event) {
    boolean intercepted = false;
    int x = (int) event.getx();
    int y = (int) event.gety();

    switch (event.getaction()) {
      case motionevent.action_down: {
        intercepted = false;
        /*if (state!=default||state!=refreshing){
        if (!mscroller.isfinished()) {
          mscroller.abortanimation();
        }}*/
        break;
      }
      case motionevent.action_move: {
        int deltax = x - mlastxintercept;
        int deltay = y - mlastyintercept;

        int firstcompletelyvisibleitemposition = -1;
        if (mlayoutmanager instanceof linearlayoutmanager) {
          linearlayoutmanager manager = (linearlayoutmanager) mlayoutmanager;
          firstcompletelyvisibleitemposition = manager.findfirstcompletelyvisibleitemposition();

        } else if (mlayoutmanager instanceof gridlayoutmanager) {
          gridlayoutmanager manager = (gridlayoutmanager) mlayoutmanager;
          firstcompletelyvisibleitemposition = manager.findfirstcompletelyvisibleitemposition();

        } else if (mlayoutmanager instanceof staggeredgridlayoutmanager) {
          staggeredgridlayoutmanager manager = (staggeredgridlayoutmanager) mlayoutmanager;
          firstcompletelyvisibleitemposition = manager.findfirstcompletelyvisibleitempositions(new int[manager.getspancount()])[0];
        }


        //        ******************这里说明什么规则下，拦截，其余代码不要动了，其余代码指的是处理滑动冲突的代码***************


        if (firstcompletelyvisibleitemposition == 0 && deltay > 0 && math.abs(deltay) > math.abs(deltax)) {//拉倒最顶部，继续往下拉，将拉出头布局，要父布局拦截
          intercepted = true;
        } else if (getscrolly() < 0) {//表示头布局已经向下拉出来，头布局已经显示了，要父布局拦截
          intercepted = true;

        } else if (deltay < 0) {
          intercepted = false;//不要父布局拦截了

        } else {
          intercepted = false;//不要父布局拦截了
        }
        //        ******************什么规则下，拦截***************

        break;
      }
      case motionevent.action_up: {
        intercepted = false;
        break;
      }
      default:
        break;
    }

    log.d(tag, "intercepted=" + intercepted);
    mlastx = x;
    mlasty = y;
    mlastxintercept = x;
    mlastyintercept = y;

    return intercepted;
  }


  /**
   * 下面不同布局，不同的滑动需求
   *
   * @param event
   * @return
   */
  @override
  public boolean ontouchevent(motionevent event) {
    mvelocitytracker.addmovement(event);
    int x = (int) event.getx();
    int y = (int) event.gety();
    switch (event.getaction()) {
      case motionevent.action_down: {
        if (!mscroller.isfinished()) {
          mscroller.abortanimation();
        }
        break;
      }
      case motionevent.action_move: {
        int deltax = x - mlastx;
        int deltay = y - mlasty;
        if (getscrolly() > 0) {
          //防止在正在刷新状态下，上拉出空白
        } else if (getscrolly() <= 0 && getscrolly() > -refreshheadviewheight * 5) {
//          最多下拉到头布局高度5倍的距离
          scrollby(0, -deltay / 2);
        }

        if (getscrolly() > -refreshheadviewheight && state != refreshing) {//头布局显示不全时，为下拉刷新pull_down_refresh状态
          state = pull_down_refresh;

          if (monpullshowviewlistener != null) {
            monpullshowviewlistener.onpulldownrefreshstate(getscrolly(), refreshheadviewheight, deltay);
          }

        }
        if (getscrolly() < -refreshheadviewheight && state != refreshing) {//头布局完全显示时，为释放刷新release_refresh状态
          state = release_refresh;
          if (monpullshowviewlistener != null) {
            monpullshowviewlistener.onreleaserefreshstate(getscrolly(), deltay);
          }

        }

        break;
      }
      case motionevent.action_up: {
        final int scrolly = getscrolly();
        //松手时，根据所处的状态，让布局滑动到不同的地方，做不同的操作
        switch (state) {

          case pull_down_refresh:
            state = default;
            //头布局没有完全显示，完全隐藏头布局
            smoothscrollby(0, -scrolly);
            break;
          case release_refresh:
            state = refreshing;
            smoothscrollby(0, -refreshheadviewheight - scrolly);


            if (monpullshowviewlistener != null) {
              monpullshowviewlistener.onrefreshingstate();
            }


            if (monpulllistener != null) {
              monpulllistener.onrefresh();
            }
            break;
          case refreshing:
            if (getscrolly() < -refreshheadviewheight) {
              smoothscrollby(0, -refreshheadviewheight - scrolly);
            } else {
              smoothscrollby(0, -scrolly);
            }
            break;
        }

        mvelocitytracker.clear();
        break;
      }
      default:
        break;
    }

    mlastx = x;
    mlasty = y;
    return true;
  }

  /**
   * 当用户使用完下拉刷新回调时，需要调用此方法，将头不去隐藏，将state恢复
   */
  public void refreshfinish() {
    smoothscrollby(0, 0 - getscrolly());
    getrecyclerview().getadapter().notifydatasetchanged();
    state = default;
    if (monpullshowviewlistener != null) {
      monpullshowviewlistener.ondefaultstate();
    }

    toast.maketext(getcontext(), "刷新成功!", toast.length_short).show();
  }

  /**
   * 当用户使用完加载更多后回调时，需要调用此方法，将state恢复
   */
  public void loadmrefinish() {
    getrecyclerview().getadapter().notifydatasetchanged();
    state = default;

    toast.maketext(getcontext(), "加载成功了!", toast.length_short).show();
  }

  /**
   * 在500毫秒内平滑地滚动多少像素点
   *
   * @param dx
   * @param dy
   */
  private void smoothscrollby(int dx, int dy) {
    mscroller.startscroll(0, getscrolly(), 0, dy, 500);
    invalidate();
  }

  @override
  public void computescroll() {
    if (mscroller.computescrolloffset()) {
      scrollto(mscroller.getcurrx(), mscroller.getcurry());
      postinvalidate();
    }
  }

  /**
   * 释放资源
   */
  @override
  protected void ondetachedfromwindow() {
    mvelocitytracker.recycle();
    super.ondetachedfromwindow();
  }


//  ***************


//  *****************

  /**
   * 回调接口
   */
  public interface onpulllistener {
    /**
     * 当下拉刷新正在刷新时，这时候可以去请求数据，记得最后调用refreshfinish()复位
     */
    void onrefresh();

    /**
     * 当加载更多时
     */
    void onloadmore();
  }


  /**
   * 回调接口，可以通过下面的回调，自定义各种状态下的显示效果
   * 可以根据下拉距离scrolly设计动画效果
   */
  public interface onpullshowviewlistener {

    /**
     * 当处于下拉刷新时，头布局显示效果
     *
     * @param scrolly    下拉的距离
     * @param headviewheight 头布局高度
     * @param deltay     movey-lastmovey,正值为向下拉
     */
    void onpulldownrefreshstate(int scrolly, int headviewheight, int deltay);

    /**
     * 当处于松手刷新时，头布局显示效果
     *
     * @param scrolly 下拉的距离
     * @param deltay movey-lastmovey,正值为向下拉
     */
    void onreleaserefreshstate(int scrolly, int deltay);

    /**
     * 正在刷新时，页面的显示效果
     */
    void onrefreshingstate();

    /**
     * 默认状态时，页面显示效果，主要是为了复位各种状态
     */
    void ondefaultstate();


  }
}

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