RecyclerView嵌套RecyclerView的条目,项目中可能会经常有这样的需求,但是我们将子条目设置为RecyclerView之后,却显示不出来。自己试了很久,终于找到了原因:必须先设置子RecylcerView的高度。你要花精力确定出子RecyclerView里面条目的高度,然后从而确定子RecyclerView的高度,设置给子RecylcerView,这样做RecyclerView就可以正确显示出子ReclyclerView。
首页布局就是一个竖直排列的RecyclerView
接下来在MainActivity对该布局进行初始化,然后制造一些假数据
protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); basicParamInit(); initData(); initRecyclerView(); } private void basicParamInit() { DisplayMetrics metric = new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(metric); screenWidth = metric.widthPixels; } private void initData() { data = new DataInfor(); ArrayListresourceList =new ArrayList<>(); resourceList.add(R.drawable.aaa); resourceList.add(R.mipmap.ic_launcher); resourceList.add(R.drawable.aaa); resourceList.add(R.mipmap.ic_launcher); resourceList.add(R.drawable.aaa); resourceList.add(R.mipmap.ic_launcher); resourceList.add(R.drawable.aaa); resourceList.add(R.mipmap.ic_launcher); data.gridData = data.horizontalData = data.verticalData = resourceList; } private void initRecyclerView() { recylcerview = (RecyclerView) findViewById(R.id.recylcerview); recylcerview.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL,false)); recylcerview.setBackgroundResource(R.color.c_e0e0e2); recylcerview.setAdapter(new RecyclerViewAdapter()); }
接下来看看RecyclerView的Adapter:
private class RecyclerViewAdapter extends RecyclerView.Adapter{ private final int HORIZONTAL_VIEW = 1000; private final int VERTICAL_VIEW = 1001; private final int GRID_VIEW = 1002; @Override public BaseHolder onCreateViewHolder(ViewGroup parent, int viewType) { switch (viewType){ case HORIZONTAL_VIEW: return new HorizontalViewHolder(R.layout.item_recyclerview,parent,viewType); case GRID_VIEW: return new GridViewHolder(R.layout.item_recyclerview,parent,viewType); case VERTICAL_VIEW: return new ItemViewHolder(R.layout.item_x2_imageview,parent,viewType); } return null; } @Override public void onBindViewHolder(BaseHolder holder, int position) { if(holder instanceof HorizontalViewHolder){ holder.refreshData(data.horizontalData,position); }else if(holder instanceof GridViewHolder){ holder.refreshData(data.gridData,position); }else if(holder instanceof ItemViewHolder){ holder.refreshData(data.verticalData.get(position - 2),position - 2); } } @Override public int getItemCount() { return 2 + data.verticalData.size(); } @Override public int getItemViewType(int position) { if(position == 0) return HORIZONTAL_VIEW; if(position == 1) return GRID_VIEW; return VERTICAL_VIEW; } }
可以看出,我们一共有三种条目类型,第一种是水平滑动的子RecyclerView,第二种是GridView形的子RecyclerView,第三种就是正常的子条目,根据viewType来返回不同的ViewHolder,到这里应该都没什么问题。
接下来就是各个类型的ViewHolder了,在Holder当中,我们要计算条目的高度然后设置给子RecyclerView
private class GridViewHolder extends BaseHolder>{ private RecyclerView item_recyclerview; private final int ONE_LINE_SHOW_NUMBER = 3; private List
data; public GridViewHolder(int viewId, ViewGroup parent, int viewType) { super(viewId, parent, viewType); item_recyclerview = (RecyclerView) itemView.findViewById(R.id.item_recyclerview); } @Override public void refreshData(List data, int position) { super.refreshData(data, position); this.data = data; //每行显示3个,水平显示 item_recyclerview.setLayoutManager(new GridLayoutManager(MainActivity.this,ONE_LINE_SHOW_NUMBER,LinearLayoutManager.HORIZONTAL,false)); ViewGroup.LayoutParams layoutParams = item_recyclerview.getLayoutParams(); //计算行数 int lineNumber = data.size()%ONE_LINE_SHOW_NUMBER==0? data.size()/ONE_LINE_SHOW_NUMBER:data.size()/ONE_LINE_SHOW_NUMBER +1; //计算高度=行数*每行的高度 +(行数-1)*10dp的margin + 10dp(为了居中) //因为每行显示3个条目,为了保持正方形,那么高度应该是也是宽度/3 //高度的计算需要自己好好理解,否则会产生嵌套recyclerView可以滑动的现象 layoutParams.height = lineNumber *(screenWidth/3) + (lineNumber-1)*dip2px(10) + dip2px(10); item_recyclerview.setLayoutParams(layoutParams); item_recyclerview.setBackgroundResource(R.color.colorPrimary); item_recyclerview.setAdapter(new GridAdapter()); } private class GridAdapter extends RecyclerView.Adapter { @Override public BaseHolder onCreateViewHolder(ViewGroup parent, int viewType) { return new ItemViewHolder(R.layout.item_x2_imageview,parent,viewType); } @Override public void onBindViewHolder(BaseHolder holder, int position) { holder.refreshData(data.get(position),position); } @Override public int getItemCount() { return data.size(); } } }
其他代码我就不贴了,想要看源码的可以直接下载:
https://github.com/z593492734/nesting-recylcerview
总体来说,RecyclerView嵌套RecyclerView是很简单的,而且也相当好用,希望这个demo可以给大家一些灵感。