android教你打造独一无二的上拉下拉刷新加载框架

其实早在去年七月，群里小伙伴就有让我共享这个。但我当时绝的技术不纯熟。代码有bug什么的。没有写出来。现在感觉整理的差不多了。就写出来让大家看看，有问题一起讨论解决。

说到刷新加载，我们第一个想到啥，对了就是swiperefreshlayout，还有什么superswiperefreshlayout，xrecyclerview等等。反正老多了，我还是之前那句话，不管用什么，我们需要知道他的原理。

打造框架开始

对于刷新加载的实现，你们第一个想到的是什么？是用swiperefresh然后在recyclerview底部加一个不同type？还是用事件拦截呢？那必须是事件拦截啊，虽然现在swiperefreshlayout很火，基本很多app都能看到他。但是遇到那种坑比公司说刷新要用自己公司logo你也没辙。对把。。好了，感觉得罪了好多公司，不管他，我们继续。

我们先看下我们的效果图：

老铁，没毛病。下面我介绍如何实现的。

下拉刷新

首先我们给出如下几个参数，后面要用：

  private nestedscrollingparenthelper helper = null;
  private boolean isrefresh = true;
  private boolean isload = true;
  //滑动的总距离
  private int totaly = 0;
  private linearlayout headerlayout = null;
  private myrecyclerview myrecyclerview = null;
  private linearlayout footerlayout = null;

既然是刷新，我们的滚动肯定是在父view之前的。所以我们需要在onnestedprescroll这个方法里面写上我们所需要改动的x，y值。

我们需要用父view去拦截它。

我们需要判断dy的值是否大于0，因为大于0是刷新操作，小于0是加载操作。然后我们需要判断recyclerview是否是纵向的而不是横向的。

public void onnestedprescroll(view target, int dx, int dy, int[] consumed) {
    if (isrefresh) {
      if (dy > 0) {
        if (myrecyclerview.isorientation(0)) {
          totaly += dy;
          if ((totaly / 2) <= 0) {
            scrollto(0, totaly / 2);
            consumed[1] = dy;
          } else {
            scrollto(0, 0);
            consumed[1] = 0;
          }
        }
        return;
      }
    }

上拉加载

上面我也说了onnestedprescroll这个方法中判断dy<0才是加载操作。所以综上所述，代码变成了这样：

 public void onnestedprescroll(view target, int dx, int dy, int[] consumed) {
    if (totaly < 0 && myrecyclerview.isorientation(0) || totaly > 0 && myrecyclerview.isorientation(1)) {
      isfling = true;
    }
    if (isrefresh) {
      if (dy > 0) {
        if (myrecyclerview.isorientation(0)) {
          totaly += dy;
          if ((totaly / 2) <= 0) {
            scrollto(0, totaly / 2);
            consumed[1] = dy;
          } else {
            scrollto(0, 0);
            consumed[1] = 0;
          }
        }
        return;
      }
    }
    if (isload) {
      if (dy < 0) {
        if (myrecyclerview.isorientation(1)) {
          totaly += dy;
          if ((totaly / 2) >= 0) {
            scrollto(0, totaly / 2);
            consumed[1] = dy;
          } else {
            scrollto(0, 0);
            consumed[1] = 0;
          }
        }
        return;
      }
    }
  }

最后我们需要在子view滑动结束后，实行如下操作：

 //子view滑动结束调用
  //dyunconsumed < 0 向下滚
  //dyunconsumed > 0 向上滚
  public void onnestedscroll(view target, int dxconsumed, int dyconsumed, int dxunconsumed, int dyunconsumed) {
    if (dyunconsumed != 0) {
      totaly += dyunconsumed;
      scrollto(0, totaly / 2);
    }
  }

其实最主要的两个方法已经解决了，其他到没什么了，这边，我把nestedscrolling的8个接口的功能和自定义recyclerview放出来。已变大家参考。希望大家都能实现自己的刷新加载。告别swiperefreshlayout。

添加header和footer

这里我们参考listview自带的addheaderview和addfooterview。代码如下：

 public void addheaderview(view headerview, int headerheight) {
    this.headerlayout.removeallviews();
    this.headerlayout.addview(headerview);
    layoutparams layoutparams = new layoutparams(layoutparams.match_parent, headerheight);
    layoutparams.topmargin = -headerheight;
    this.headerlayout.setlayoutparams(layoutparams);
  }

  public void addfooterview(view footerview, int footerheight) {
    this.footerlayout.removeallviews();
    this.footerlayout.addview(footerview);
    this.footerlayout.setlayoutparams(new layoutparams(layoutparams.match_parent, footerheight));
  }

几个接口的实现

 public boolean onstartnestedscroll(view child, view target, int nestedscrollaxes) {
    return true;
  }

  public void onnestedscrollaccepted(view child, view target, int axes) {
    helper.onnestedscrollaccepted(child, target, axes);
  }

  //父view拦截子view的滚动
  public void onnestedprescroll(view target, int dx, int dy, int[] consumed) {
    if (totaly < 0 && myrecyclerview.isorientation(0) || totaly > 0 && myrecyclerview.isorientation(1)) {
      isfling = true;
    }
    if (isrefresh) {
      if (dy > 0) {
        if (myrecyclerview.isorientation(0)) {
          totaly += dy;
          if ((totaly / 2) <= 0) {
            scrollto(0, totaly / 2);
            consumed[1] = dy;
          } else {
            scrollto(0, 0);
            consumed[1] = 0;
          }
        }
        return;
      }
    }
    if (isload) {
      if (dy < 0) {
        if (myrecyclerview.isorientation(1)) {
          totaly += dy;
          if ((totaly / 2) >= 0) {
            scrollto(0, totaly / 2);
            consumed[1] = dy;
          } else {
            scrollto(0, 0);
            consumed[1] = 0;
          }
        }
        return;
      }
    }
  }

  //子view滑动结束调用
  //dyunconsumed < 0 向下滚
  //dyunconsumed > 0 向上滚
  public void onnestedscroll(view target, int dxconsumed, int dyconsumed, int dxunconsumed, int dyunconsumed) {
    if (dyunconsumed != 0) {
      totaly += dyunconsumed;
      scrollto(0, totaly / 2);
    }
  }

  public void onstopnestedscroll(view child) {
    helper.onstopnestedscroll(child);
    if (ontouchuplistener != null) {
      isfling = false;
      ontouchuplistener.touchup();
    }
  }

  public boolean onnestedfling(view target, float velocityx, float velocityy, boolean consumed) {
    return isfling;
  }

  public boolean onnestedprefling(view target, float velocityx, float velocityy) {
    return isfling;
  }

  public int getnestedscrollaxes() {
    return helper.getnestedscrollaxes();
  }

自定义recyclerview

既然是自己写的刷新加载框架，总不能还有自定义layout中在放个recyclerview。多麻烦，自定义一个，直接放在里面，然后分别放个header和footer 就没必要每次有页面用到刷新都要写一个布局。3个布局解决整个项目的刷新和加载。话不多说，代码如下：

  private class myrecyclerview extends recyclerview {
    private staggeredgridlayoutmanager staggeredgridlayoutmanager = null;
    private linearlayoutmanager linearlayoutmanager = null;
    private gridlayoutmanager gridlayoutmanager = null;
    private boolean isscrollload = false;
    private boolean isscrollrefresh = false;

    public myrecyclerview(context context) {
      super(context);
      setverticalfadingedgeenabled(false);
      sethorizontalfadingedgeenabled(false);
      setverticalscrollbarenabled(false);
      sethorizontalscrollbarenabled(false);
      setoverscrollmode(over_scroll_never);
      setitemanimator(new defaultitemanimator());
    }

    private void setmylayoutmanager(layoutmanager layoutmanager) {
      if (layoutmanager instanceof staggeredgridlayoutmanager) {
        staggeredgridlayoutmanager = (staggeredgridlayoutmanager) layoutmanager;
      } else if (layoutmanager instanceof gridlayoutmanager) {
        gridlayoutmanager = (gridlayoutmanager) layoutmanager;
      } else if (layoutmanager instanceof linearlayoutmanager) {
        linearlayoutmanager = (linearlayoutmanager) layoutmanager;
      }
      setlayoutmanager(layoutmanager);
      if (!isvertical()) {
        throw new nullpointerexception("vertical!");
      }
    }

    private boolean isorientation(int orientation) {//orientation,0代表向下，1代表向上
      if (orientation == 0)
        return iscanpulldown();
      else if (orientation == 1)
        return iscanpullup();
      return false;
    }

    private boolean iscanpulldown() {
      return !canscrollvertically(-1);
    }

    private boolean iscanpullup() {
      return !canscrollvertically(1);
    }

//    private int scrollload() {
//      int lastitem = 0;
//      int itemcount = 0;
//      int spancount = 1;
//      if (staggeredgridlayoutmanager != null) {
//        lastitem = staggeredgridlayoutmanager.findlastvisibleitempositions(null)[0];
//        itemcount = staggeredgridlayoutmanager.getitemcount();
//        spancount = staggeredgridlayoutmanager.getspancount();
//      } else if (linearlayoutmanager != null) {
//        lastitem = linearlayoutmanager.findlastvisibleitemposition();
//        itemcount = linearlayoutmanager.getitemcount();
//        spancount = 1;
//      } else if (gridlayoutmanager != null) {
//        lastitem = gridlayoutmanager.findlastvisibleitemposition();
//        itemcount = gridlayoutmanager.getitemcount();
//        spancount = gridlayoutmanager.getspancount();
//      }
//      return ((itemcount - 1) / spancount + 1) - (lastitem / spancount + 1);
//    }

    private boolean isvertical() {
      if (staggeredgridlayoutmanager != null)
        return staggeredgridlayoutmanager.getorientation() == staggeredgridlayoutmanager.vertical;
      else if (linearlayoutmanager != null)
        return linearlayoutmanager.getorientation() == linearlayoutmanager.vertical;
      else if (gridlayoutmanager != null)
        return gridlayoutmanager.getorientation() == gridlayoutmanager.vertical;
      return false;
    }

//    public void onscrolled(int dx, int dy) {
//      if (dy > 0 && !isscrollload) {
//        if (olior != null) {
//          onscrolllistener.scrollload(sc````````
`
``
llload());//传递滚动到倒数第几行
//        }
//      }
//    }
  }

这样我们变实现了自己的刷新加载框架，代码我已上传：swpullrecyclerlayout_jb51.rar

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。