Android Studio：如何在 recyclerview 上添加过滤器以及如何实现它

Question

private class ValueFilter extends Filter {
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            FilterResults results = new FilterResults();

            dbList = itemListCopy;

            if (constraint != null && constraint.length() > 0) {
                List<DbItemModel> filterList = new ArrayList();
                for (int i = 0; i < dbList.size(); i++) {
                    String str = (dbList.get(i).getItemDetails().toUpperCase()) + " " +
                            (dbList.get(i).getGroupName().toUpperCase()) + " " +
                            (dbList.get(i).getItemName().toUpperCase()) + " ";
                    if (str.contains(constraint.toString().toUpperCase())) {
                        filterList.add(dbList.get(i));
                    }
                }
                dbList = filterList;
                results.count = filterList.size();
                results.values = filterList;
            } else {
                results.count = itemListCopy.size();
                results.values = itemListCopy;
            }
            return results;
        }

        @Override
        protected void publishResults(CharSequence charSequence, FilterResults results) {
            dbList = (List<DbItemModel>) results.values;
            notifyDataSetChanged();
        }
    }

我想在我的 recyclerview 上添加过滤器并将其用于搜索功能。请。帮助我，如果你能让它变得简单。谢谢大家。

Answer 1

第 1 步为您的适配器实现 Filterable 接口并实现其方法

例如：

 public class MyAdapter extends
    RecyclerView.Adapter<MyAdapter.ViewHolder> implements Filterable{
  // Other code 

   }

第二步创建一个扩展过滤器的类

例如：

private class ValueFilter extends Filter {

@Override
protected FilterResults performFiltering(CharSequence constraint) {
  FilterResults results = new FilterResults();
  contactList = contactsListCopy;
// Replace with your own logic 
  if (constraint != null && constraint.length() > 0) {
    List<Contacts> filterList = new ArrayList();
    for (int i = 0; i < contactList.size(); i++) {
      if ((contactList.get(i).getName().toUpperCase())
          .contains(constraint.toString().toUpperCase())) {
        filterList.add(contactList.get(i));
      }
    }
    contactList = filterList;
    results.count = filterList.size();
    results.values = filterList;
  } else {
    results.count = contactsListCopy.size();
    results.values = contactsListCopy;
  }
  return results;
}

@Override
protected void publishResults(CharSequence charSequence, FilterResults results) {
  contactList = (List<Contacts>) results.values;
  notifyDataSetChanged();
}

}

第3步：为简单起见添加

<android.support.v7.widget.SearchView
  android:id="@+id/search"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"/>

在回收站视图上方的片段/活动布局中

您的活动/片段中的第 4 步实现 SearchView.OnQueryTextListener 并初始化视图

 SearchView sv = (SearchView) itemView.findViewById(R.id.search);
 sv.setVisibility(View.VISIBLE);
 sv.setQueryHint("Search Here");
sv.setOnQueryTextListener(this);

第五步：实现所有方法

步骤 6 像这样更新适配器

      @Override
  public boolean onQueryTextSubmit(String query) {
    mAdapter.getFilter().filter(query);
    return true;
  }

  @Override
  public boolean onQueryTextChange(String newText) {
    mAdapter.getFilter().filter(newText);
    return true;
}