其實早在去年七月，群里小伙伴就有讓我共享這個。但我當(dāng)時絕的技術(shù)不純熟。代碼有bug什么的。沒有寫出來。現(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，我們第一個想到啥，對了就是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
對于刷新加載的實現(xiàn)，你們第一個想到的是什么？是用swiperefresh然后在recyclerview底部加一個不同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。下面我介紹如何實現(xiàn)的。
下拉刷新
首先我們給出如下幾個參數(shù)，后面要用：
private NestedScrollingParentHelper helper = null; private boolean IsRefresh = true; private boolean IsLoad = true; //滑動的總距離 private int totalY = 0; private LinearLayout headerLayout = null; private MyRecyclerView myRecyclerView = null; private LinearLayout footerLayout = null;
既然是刷新，我們的滾動肯定是在父view之前的。所以我們需要在onNestedPreScroll這個方法里面寫上我們所需要改動的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，因為大于0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滑動結(jié)束后，實行如下操作：
//子view滑動結(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); } }其實最主要的兩個方法已經(jīng)解決了，其他到?jīng)]什么了，這邊，我把nestedscrolling的8個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)); }幾個接口的實現(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 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recyclerview。多麻煩，自定義一個，直接放在里面，然后分別放個header和footer 就沒必要每次有頁面用到刷新都要寫一個布局。3個布局解決整個項目的刷新和加載。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());//傳遞滾動到倒數(shù)第幾行// }// }// } }這樣我們變實現(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內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持武林網(wǎng)。
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