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android教你打造獨(dú)一無二的上拉下拉刷新加載框架

 更新時(shí)間:2017年03月21日 08:22:07   作者:我就是馬云飛  
本篇文章主要介紹了android教你打造獨(dú)一無二的下拉刷新加載框架,具有一定的參考價(jià)值,有興趣的可以了解一下。

其實(shí)早在去年七月,群里小伙伴就有讓我共享這個(gè)。但我當(dāng)時(shí)絕的技術(shù)不純熟。代碼有bug什么的。沒有寫出來?,F(xiàn)在感覺整理的差不多了。就寫出來讓大家看看,有問題一起討論解決。

說到刷新加載,我們第一個(gè)想到啥,對(duì)了就是swiperefreshlayout,還有什么SuperSwiperefreshlayout,XRecyclerView等等。反正老多了,我還是之前那句話,不管用什么,我們需要知道他的原理。

打造框架開始

對(duì)于刷新加載的實(shí)現(xiàn),你們第一個(gè)想到的是什么?是用swiperefresh然后在recyclerview底部加一個(gè)不同type?還是用事件攔截呢?那必須是事件攔截啊,雖然現(xiàn)在swiperefreshlayout很火,基本很多app都能看到他。但是遇到那種坑比公司說刷新要用自己公司logo你也沒轍。對(duì)把。。好了,感覺得罪了好多公司,不管他,我們繼續(xù)。

我們先看下我們的效果圖:

老鐵,沒毛病。下面我介紹如何實(shí)現(xiàn)的。

下拉刷新

首先我們給出如下幾個(gè)參數(shù),后面要用:

  private NestedScrollingParentHelper helper = null;
  private boolean IsRefresh = true;
  private boolean IsLoad = true;
  //滑動(dòng)的總距離
  private int totalY = 0;
  private LinearLayout headerLayout = null;
  private MyRecyclerView myRecyclerView = null;
  private LinearLayout footerLayout = null;

既然是刷新,我們的滾動(dòng)肯定是在父view之前的。所以我們需要在onNestedPreScroll這個(gè)方法里面寫上我們所需要改動(dòng)的x,y值。

我們需要用父view去攔截它。

我們需要判斷dy的值是否大于0,因?yàn)榇笥?是刷新操作,小于0是加載操作。然后我們需要判斷recyclerview是否是縱向的而不是橫向的。

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;
      }
    }

上拉加載

上面我也說了onNestedPreScroll這個(gè)方法中判斷dy<0才是加載操作。所以綜上所述,代碼變成了這樣:

 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;
      }
    }
  }

最后我們需要在子view滑動(dòng)結(jié)束后,實(shí)行如下操作:

 //子view滑動(dòng)結(jié)束調(diào)用
  //dyUnconsumed < 0 向下滾
  //dyUnconsumed > 0 向上滾
  public void onNestedScroll(View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
    if (dyUnconsumed != 0) {
      totalY += dyUnconsumed;
      scrollTo(0, totalY / 2);
    }
  }

其實(shí)最主要的兩個(gè)方法已經(jīng)解決了,其他到?jīng)]什么了,這邊,我把nestedscrolling的8個(gè)接口的功能和自定義recyclerview放出來。已變大家參考。希望大家都能實(shí)現(xiàn)自己的刷新加載。告別swiperefreshlayout。

添加header和footer

這里我們參考listview自帶的addheaderview和addfooterview。代碼如下:

 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));
  }

幾個(gè)接口的實(shí)現(xiàn)

 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攔截子view的滾動(dòng)
  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滑動(dòng)結(jié)束調(diào)用
  //dyUnconsumed < 0 向下滾
  //dyUnconsumed > 0 向上滾
  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();
  }

自定義recyclerview

既然是自己寫的刷新加載框架,總不能還有自定義layout中在放個(gè)recyclerview。多麻煩,自定義一個(gè),直接放在里面,然后分別放個(gè)header和footer 就沒必要每次有頁面用到刷新都要寫一個(gè)布局。3個(gè)布局解決整個(gè)項(xiàng)目的刷新和加載。話不多說,代碼如下:

  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());//傳遞滾動(dòng)到倒數(shù)第幾行
//        }
//      }
//    }
  }

這樣我們變實(shí)現(xiàn)了自己的刷新加載框架,代碼我已上傳:SWPullRecyclerLayout_jb51.rar

以上就是本文的全部?jī)?nèi)容,希望對(duì)大家的學(xué)習(xí)有所幫助,也希望大家多多支持腳本之家。

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