Question

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

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

并实施了：

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

这是MyFilter类的实现：

    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，在我的活动中，我的editText小部件实现如下：

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Filter类（参见上面的代码），当它到达：

时

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

它返回一个如下所示的异常：

03-08 17：06：36.085 27853-27984 / com.name.cardbox W / Filter：performFiltering（）期间发生异常！ java.lang.UnsupportedOperationException at java.util.AbstractList.add（AbstractList.java:404） at java.util.AbstractList.add（AbstractList.java:425）在com.birsan.cardbox.FolderAdapter $ MyFilter.performFiltering（FolderAdapter.java:288）在android.widget.Filter $ RequestHandler.handleMessage（Filter.java:234）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:135）在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，所以我认为这就是问题所在。我究竟做错了什么？

Answer 1

好吧，似乎过滤器不适用于List＆lt;＆gt;对象。我改变了：

filteredNames

来自

列表＆lt; FolderRow＆gt;

反对

ArrayList＆lt; FolderRow＆gt;

。这让它发挥作用。

RecyclerView.Adapter自定义筛选器异常

1 个答案: