PullToRefreshLayout +RecyclerView 实现上拉加载下拉刷新
16lz
2021-01-23
1 ，xml布局：com.xinshangyun.app.ui.view.PullToRefreshLayout android:id="@+id/fudan_refresh_view" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@+id/title_bar" android:divider="@android:color/transparent" android:dividerHeight="@dimen/dp_0" android:listSelector="@android:color/transparent">
2，自定义的RecycleView
public class PullableRecyclerView extends RecyclerView implements Pullable { private int lastPosition; private boolean mCanPullDown = true; private boolean mCanPullUp = true; private boolean pd = true; public PullableRecyclerView(Context context) { super(context); } public PullableRecyclerView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); } public PullableRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } //判断是否可以下拉刷新 public void setNo(boolean pd){ this.pd = pd; } //是否可以下拉 public void setCanPullDown(boolean canPullDown) { this.mCanPullDown = canPullDown; } public void setCanPullUp(boolean canPullUp) { this.mCanPullUp = canPullUp; } /** * 可以下拉 * * @return */ @Override public boolean canPullDown() { if(mCanPullDown) { if (getChildCount() == 0) { return true; } else if (getChildAt(0).getTop() >= 0) { if (getLayoutManager() instanceof LinearLayoutManager) { int firstVisibleItem = ((LinearLayoutManager) getLayoutManager()).findFirstVisibleItemPosition(); if (firstVisibleItem == 0) { return true; } } else if (getLayoutManager() instanceof GridLayoutManager) { int firstVisibleItem = ((GridLayoutManager) getLayoutManager()).findFirstVisibleItemPosition(); if (firstVisibleItem == 0) { return true; } }else if(getLayoutManager() instanceof StaggeredGridLayoutManager){ //因为StaggeredGridLayoutManager的特殊性可能导致最后显示的item存在多个，所以这里取到的是一个数组 //得到这个数组后再取到数组中position值最大的那个就是最后显示的position值了// int[] lastPositionsDown = new int[((StaggeredGridLayoutManager) getLayoutManager()).getSpanCount()]; int lastPositionsDown[] = ((StaggeredGridLayoutManager)getLayoutManager()).findFirstVisibleItemPositions(null); if(findMin(lastPositionsDown)==0){ return true; } } } } return false; } /** * 可以上拉 * * @return */ @Override public boolean canPullUp() { if(mCanPullUp) { if (getChildCount() == 0) { return true; } else { RecyclerView.LayoutManager layoutManager = getLayoutManager(); if (layoutManager instanceof GridLayoutManager) { //通过LayoutManager找到当前显示的最后的item的position lastPosition = ((GridLayoutManager) layoutManager).findLastVisibleItemPosition(); } else if (layoutManager instanceof LinearLayoutManager) { lastPosition = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition(); } else if (layoutManager instanceof StaggeredGridLayoutManager) { //因为StaggeredGridLayoutManager的特殊性可能导致最后显示的item存在多个，所以这里取到的是一个数组 //得到这个数组后再取到数组中position值最大的那个就是最后显示的position值了 int[] lastPositions = new int[((StaggeredGridLayoutManager) layoutManager).getSpanCount()]; ((StaggeredGridLayoutManager) layoutManager).findLastVisibleItemPositions(lastPositions); lastPosition = findMax(lastPositions); } //时判断界面显示的最后item的position是否等于itemCount总数-1也就是最后一个item的position //如果相等则说明已经滑动到最后了 if (lastPosition == getLayoutManager().getItemCount()-1 && this.computeVerticalScrollExtent() + this.computeVerticalScrollOffset() >= this.computeVerticalScrollRange()) { return true; } } } return false; } private int findMax(int[] lastPositions) { int max = lastPositions[0]; for (int value : lastPositions) { if (value > max) { max = value; } } return max; } private int findMin(int[] lastPositions) { int min = lastPositions[0]; for (int value : lastPositions) { if (value< min) { min = value; } } return min; }}
更多相关文章
- 什么是链表？链表与数组的区别？
- C# 数组作为参数传递出现的问题解决
- 第三章C++：字符串string、向量vector和数组
- Ruby如何创建数组
- C++实现在二维数组中的查找
- c语言数组怎么定义？
- c语言数组怎么输入？
- 二维数组怎么定义
- c语言中二维数组怎么用？