安卓：过滤自定义适配器的结果没有在UI反映 [英] Android: Results of filtering custom adapter are not reflecting in the UI

问题描述

在我的应用程序，我从获取Web服务器的数据并显示在列表视图中的数据。我的列表视图适配器包含图片和文字。现在，我要过滤列表视图。对于这一点，我在自定义适配器已实施过滤的接口。但是，它不给予任何结果。我搜索了很多，但couldn'tcome援引任何结果。这里是我的code：

In my app, I am fetching data from web server and showing the data in a list view. The adapter for my list view contains both image and text. Now,I want to filter list view. For this, I had implemented Filterable interface in my custom adapter. But, it is not giving any result. I searched alot but couldn'tcome toany result. Here's my code:

MainActivity

Runnable r = new Runnable() 
        {
            @Override
            public void run() 
            { 
                listMainMenu.setAdapter(mMenuAdapter);
                listMainMenu.setTextFilterEnabled(true);
                mMenuAdapter.notifyDataSetChanged();
                pd.dismiss();
                updateUI = false;
            }//run
        };

文字观察者类

_txtAutoSearch.addTextChangedListener(filterTextWatcher);

private TextWatcher filterTextWatcher = new TextWatcher() {
    public void afterTextChanged(Editable s) {
        Log.v(TAG+" filtertextwatcher", "afterTextChanged");
    }//afterTextChanged

    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        Log.v(TAG+" filtertextwatcher", "beforeTextChanged");
    }//beforeTextChanged

    public void onTextChanged(CharSequence s, int start, int before, int count) {
        Log.v(TAG+" filtertextwatcher", "onTextChanged");
        ((Filterable) listMainMenu.getAdapter()).getFilter().filter(s.toString());
    }//onTextChanged
};

我的自定义适配器：

    public class MainMenuAdapter extends BaseAdapter implements Filterable {
    Context ctx;
    ArrayList<MainCategoryDAO> mainCatDAOList;
    public static final String TAG = "MainMenuAdapter";
    ArrayList<MainCategoryDAO> arrayList;

    public MainMenuAdapter(Context ctx, ArrayList<MainCategoryDAO> mainCatDAOList) {
        this.ctx = ctx;
        this.mainCatDAOList = mainCatDAOList;
    }//Constructor

    public int getCount() {
        return mainCatDAOList.size();
    }//getCount

    public Object getItem(int position) {
        return mainCatDAOList.get(position);
    }//getItem

    public long getItemId(int position) {
        return 0;
    }//getItemId

    class ViewHolder {
        ImageView imgCategoryIcon;
        TextView txtCategoryName;
    }//ViewHolder

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if(convertView == null) {
            convertView = LayoutInflater.from(parent.getContext()).inflate(R.layout.main_menu_adapter, null);
            holder = new ViewHolder();
            holder.imgCategoryIcon = (ImageView)convertView.findViewById(R.id.imgCategoryIcon);
            holder.txtCategoryName = (TextView)convertView.findViewById(R.id.txtCategoryName);
            convertView.setTag(holder);
        }//if
        else {
            holder = (ViewHolder) convertView.getTag();
        }//else
        Typeface cat_nameTF = Typeface.createFromAsset(ctx.getAssets(), "fonts/arial.ttf");
        Log.v(TAG, "category name "+ mainCatDAOList.get(position).getCategory_name());
        Log.v(TAG, "category icon "+ mainCatDAOList.get(position).getCategory_icon());
        BitmapManager.INSTANCE.loadBitmap(mainCatDAOList.get(position).getCategory_icon(), holder.imgCategoryIcon, 50, 50);
        holder.txtCategoryName.setTypeface(cat_nameTF);
        holder.txtCategoryName.setText(mainCatDAOList.get(position).getCategory_name());
        Log.v(TAG, "text view category name "+ holder.txtCategoryName.getText());
        return convertView;
    }//getView

    @Override
public Filter getFilter() 
{
    Filter mFilter = new Filter() 
    {

        @SuppressWarnings("unchecked")
        @Override
        protected void publishResults(CharSequence constraint,
                FilterResults results) 
        {
            Log.v(TAG+" getFilter", "publishResults called");
            arrayList = (ArrayList<MainCategoryDAO>) results.values;
            Log.v(TAG+" getFilter", "publishResults arrayList size "+arrayList.size());
            for(int i = 0; i < arrayList.size(); i++)
            {
                Log.v(TAG+" getFilter filtered name", " "+arrayList.get(i).getCategory_name());
            }//for
            notifyDataSetChanged();
        }//publishResults

        @Override
        protected FilterResults performFiltering(CharSequence constraint) 
        {
            Log.v(TAG+" getFilter", "performFiltering called");
            FilterResults results = new FilterResults();
            ArrayList<MainCategoryDAO> FilteredArrList = new ArrayList<MainCategoryDAO>();

            if (constraint == null || constraint.length() == 0) 
            {
                Log.v(TAG+" getFilter", "if, constraint.length null or 0");
                results.count = mainCatDAOList.size();
                results.values = mainCatDAOList;
            }//if 
            else 
            {
                Log.v(TAG+" getFilter", "else, constraint.length not 0");
                constraint = constraint.toString();
                Log.v(TAG+" getFilter", "else, constraint = "+constraint);
                for (int i = 0; i < mainCatDAOList.size(); i++) 
                {
                    Log.v(TAG+" getFilter", "for loop, constraint.length not null or 0");
                    String data = mainCatDAOList.get(i).getCategory_name();
                    Log.v(TAG+" getFilter", "else, data to check "+data);
                    if (data.toLowerCase().startsWith(constraint.toString()))   
                    {
                        Log.v(TAG+" getFilter", "if in for loop, constraint.length not null or 0");
                        FilteredArrList.add(mainCatDAOList.get(i));
                    }//if
                }//for
                results.count = FilteredArrList.size();
                results.values = FilteredArrList;
            }//else
            return results;
        }//performFiltering
    };
    return mFilter;
}//getFilter
}//MainMenuAdapter

经测试，我发现它过滤结果，但是，改变也不会在列表视图反映。我甚至尝试设置listview.setTextFilterEnabled（）为真，但它也没有工作。虽然我logcat中，我可以看到筛选值。但没有得到为什么同样未在UI反射

Upon testing, I found that it is filtering the result but, changes are not reflecting in listview. I even tried setting listview.setTextFilterEnabled() to true, but it also didn't worked. While on my logcat, I can see the filtered values. but not getting why the same is not reflecting in the UI.

推荐答案

这是正常的，你看不到任何用户界面的变化，因为你不是过滤后的更新数据的右侧列表。你的 MainMenuAdapter 是基于数据的 mainCatDAOList 名单上，但在 publishResults 方法，其中适配器的数据应该被刷新你做的：

It's normal that you don't see any UI changes, because you aren't updating the right list of data after the filtering. Your MainMenuAdapter is based on the mainCatDAOList list of data, but in the publishResults method where the adapter's data should be refreshed you do:

arrayList = (ArrayList<MainCategoryDAO>) results.values;
notifyDataSetChanged();

正如你可以看到你更新的ArrayList 通过过滤值，而不是 mainCatDAOList 这样的适配器没有按看不到任何变化。所以，你的code应该是：

As you can see you're updating the arrayList with the filtered values instead of mainCatDAOList so the adapter doesn't see any changes. So your code should be:

protected void publishResults(CharSequence constraint,
            FilterResults results) {
        Log.v(TAG+" getFilter", "publishResults called");
        mainCatDAOList = (ArrayList<MainCategoryDAO>) results.values;
        Log.v(TAG+" getFilter", "publishResults arrayList size "+arrayList.size());
        for(int i = 0; i < arrayList.size(); i++)
        {
            Log.v(TAG+" getFilter filtered name", " "+arrayList.get(i).getCategory_name());
        }//for
        notifyDataSetChanged();
    }

此外，你应该有数据的初步名单的副本以用于过滤，否则会无法恢复到满值的集合。

Also you should have a copy of the initial list of data to be used for filtering, otherwise you'll not be able to return to the full set of values.

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