强制RecyclerView调用onCreateViewHolder [英] Force RecyclerView to call onCreateViewHolder

问题描述

我有一个RecyclerView，可以将项目显示为列表，小网格或大网格，并且可以在运行时进行更改.根据用户选择的样式，我在onCreateViewHolder中填充不同的布局.

我还使用layoutManger.setSpanSizeLookUp()在样式之间进行切换.我的代码看起来像这样

I have a RecyclerView that can show items as list, small grids or large grid and this can be change at runtime. Depending on what style user chooses i inflate different layout in onCreateViewHolder.

I also use layoutManger.setSpanSizeLookUp() to switch between styles. My code looks like this

layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
        @Override
        public int getSpanSize(int position) {
            if(showType == ProductAdapter.SHOW_TYPE_SMALL_GRID)
                return 1;
            else
                return columnCount; //show one item per row
        }
    });

@Override
public void onClick(View v) {
    if(showType == ProductAdapter.SHOW_TYPE_SMALL_GRID)
        showType = ProductAdapter.SHOW_TYPE_LARGE_GRID;
    else
        showType = ProductAdapter.SHOW_TYPE_SMALL_GRID;


    int firstVisibleItem = layoutManager.findFirstVisibleItemPosition();
    adapter = new ProductAdapter(getActivity(), productList, showType);
    recyclerView.setAdapter(adapter);
    layoutManager.scrollToPosition(firstVisibleItem);
}

问题是每次用户更改样式时都要强制调用onCreateViewHolder我正在创建一个新对象.还有其他办法吗?强制onBindViewHolder()被召回.我只是使用adapter.notifyDataSetChanged()我怎么能为onCreateViewHolder?得到类似的东西

任何不使用多个适配器的解决方案就足够了！

The problem is to force onCreateViewHolder to be called I'm creating a new object every time user changes the style. Is there any other way?! to force onBindViewHolder() to be recalled. I simply use adapter.notifyDataSetChanged() How can i get something similar for onCreateViewHolder?

Any solution that doesn't uses multiple adapters is good enough!

推荐答案

您需要做的是:

1. 修改您的Adapter:

• 指定Adapter可以充气的两种Views类型:

• Specify two types of Views that your Adapter can inflate:

private static final int LARGE_GRID_ITEM = -1;
private static final int SMALL_GRID_ITEM = -2;

• 创建一个可以存储当前类型mCurrentType

  使用您的Adapter's

  Use your Adapter's getItemViewType. For example like this:

  @Override
  public int getItemViewType (int position) {
      return mCurrentType;
  }
  

  • 在createViewHolder中，使用viewType决定需要创建哪种类型的ViewHolder.
  • In your createViewHolder use the viewType to decide what type of ViewHolder you need to create.

  public final RecyclerView.ViewHolder createViewHolder (ViewGroup parent, int viewType){
      if (viewType == LARGE_GRID_ITEM) {
          //return large grid view holder
      } else {
          //return small grid view holder
      }
  }
  

  • 此外，您可以创建方法:

  public void toggleItemViewType () {
      if (mCurrentType == LARGE_GRID_ITEM){
          mCurrentType = SMALL_GRID_ITEM;
      } else {
          mCurrentType = LARGE_GRID_ITEM;
      }
  }
  
  public boolean displaysLargeGrid(){
      return mCurrentType == LARGE_GRID_ITEM;
  }
  

  1. 修改您发布的代码:

  layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
          @Override
          public int getSpanSize(int position) {
              if (adapter.displaysLargeGrid()) {
                  return 1;
              } else {
                  return columnCount; //show one item per row
              }
          }
      });
  
  @Override
  public void onClick(View v) {
      adapter.toggleItemViewType();
      adapter.notifyDataSetChanged();
  }
  

  这篇关于强制RecyclerView调用onCreateViewHolder的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！