RecyclerView.Adapter 自定义过滤器异常

Question

我有一个自定义 RecyclerView.Adapter class，我在其中实现了 Filterable 并使用了接口方法重写，如下所示：

private MyFilter myFilter = new MyFilter(); // Class implemented below

并且还实现了：

@Override
public Filter getFilter() {
    return myFilter;
}

这是 MyFilter class 实现：

    public class MyFilter extends Filter {


        @Override
        protected Filter.FilterResults performFiltering(CharSequence constraint) {

            FilterResults filterResult = new FilterResults();

            // If the constraint is 0 return the original data
            if(constraint.length() == 0) {

                filterResult.values = data;
                filterResult.count = data.size();
                return filterResult;

            }

            // Method local properties used to assemble the filtered list
            //String folderName;
            //String cardsNumber;
            //String rowId;
            String tempConstraint = constraint.toString().toLowerCase();

            // Iterate through the original data array
            for (int i = 0; i < data.size(); i++) {

                // Get the folder name from the data array
//                folderName = data.get(i).familyName;
//                cardsNumber = data.get(i).numOfCards;
//                rowId = data.get(i).folderRowId;

                // Check to see if the constraint variable corresponds to the folder name or to the
                // number of cards belonging to this particular folder
                if(data.get(i).familyName.toString().toLowerCase().contains(tempConstraint)) {

                    tempFolderRow = new FolderRow();

                    tempFolderRow.familyName = data.get(i).familyName;
                    tempFolderRow.numOfCards = data.get(i).numOfCards;
                    tempFolderRow.folderRowId = data.get(i).folderRowId;

                    // Add this object to the updated filtered list
                    filteredNames.add(data.get(i));

                }
            }

            // Assign the new list to the object filterResult for return
            filterResult.values = filteredNames;
            filterResult.count = filteredNames.size();

            return filterResult;
        }

        @Override
        protected void publishResults(CharSequence constraint, Filter.FilterResults results) {

            if(results.values != null) {

                Log.e("Values: ", results.values.toString());
            }

            notifyDataSetChanged();
        }
    }

接下来，在我的 activity 中，我的 editText 小部件是这样实现的：

searchView.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {


        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s) {
            // Filter the folder adapter
            mAdapterFolder.getFilter().filter(s);
        }

调试我的过滤器 class（见上面的代码），当它到达：

filteredNames.add(data.get(i)); // filteredNames is a List<FolderRow> obj

它 returns 一个看起来像这样的异常：

03-08 17:06:36.085 27853-27984/com.name.cardbox W/Filter﹕ An exception occured during performFiltering()! java.lang.UnsupportedOperationException at java.util.AbstractList.add(AbstractList.java:404) at java.util.AbstractList.add(AbstractList.java:425) at com.birsan.cardbox.FolderAdapter$MyFilter.performFiltering(FolderAdapter.java:288) at android.widget.Filter$RequestHandler.handleMessage(Filter.java:234) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.os.HandlerThread.run(HandlerThread.java:61)

还有一件事，如果我注释掉发生异常的行，(filteredNames.add(data.get(i));) 之前的 for 循环工作正常，所以我认为这是问题出在哪里。我究竟做错了什么？

Answer 1

好的，过滤器似乎不能很好地与 List<> 对象一起使用。我改变了：

filteredNames

从

List < FolderRow >

反对

ArrayList < FolderRow >

。这使它工作。

RecyclerView.Adapter 自定义过滤器异常

RecyclerView.Adapter custom filter exception

android

android-adapter

android-recyclerview