Question

我正在尝试使用TextChangedListener在ListView上实现搜索功能。但是在EditText中添加了一些字符后; ListView变为空白。我在ArrayAdapter类中实现了filter方法。

我从JSON获取数据。

这是我的代码：

UserList.java

public class UserList extends AppCompatActivity {

private ListView listView;
private ArrayList<MyDataModel> list;
private MyArrayAdapter adapter;
private EditText search;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.user_list);

    search = (EditText) findViewById(R.id.search);

    //Array List for Binding Data from JSON to this List
    list = new ArrayList<>();

    //Binding that List to Adapter
    adapter = new MyArrayAdapter(this, list);

    //Getting List and Setting List Adapter
    listView = (ListView) findViewById(R.id.listView);
    listView.setAdapter(adapter);

    listView.setTextFilterEnabled(true);
    search.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) {

            String text = search.getText().toString().toLowerCase(Locale.getDefault());
            adapter.filter(text);
        }

        @Override
        public void afterTextChanged(Editable s) {
        }
    });


    //Checking Internet Connection
    if (InternetConnection.checkConnection(getApplicationContext())) {
        new GetDataTask().execute();
    } else {
        Snackbar.make(findViewById(R.id.parentLayout),"Internet Connection Not Available", Snackbar.LENGTH_LONG).show();
    }
}

//Creating Get Data Task for Getting Data From Web
class GetDataTask extends AsyncTask<Void, Void, Void> {

    ProgressDialog dialog;
    int jIndex;
    int x;

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        //Progress Dialog for User Interaction
        x=list.size();

        if(x==0)
            jIndex=0;
        else
            jIndex=x;

        dialog = new ProgressDialog(UserList.this);
        dialog.setTitle("Please Wait..."+x);
        dialog.setMessage("Retrieving Data");
        dialog.show();

    }

    @Nullable
    @Override
    protected Void doInBackground(Void... params) {

        //Getting JSON Object from Web Using okHttp
        JSONObject jsonObject = JSONParser.getDataFromWeb();

        try {

            if (jsonObject != null) {

                if(jsonObject.length() > 0) {

                    JSONArray array = jsonObject.getJSONArray(Keys.KEY_CONTACTS);

                    //Check Length of Array...
                    int lenArray = array.length();
                    if(lenArray > 0) {
                        for( ; jIndex < lenArray; jIndex++) {

                            //Creating Every time New Object and adding to List
                            MyDataModel model = new MyDataModel();

                            JSONObject innerObject = array.getJSONObject(jIndex);
                            String name = innerObject.getString(Keys.KEY_NAME);

                            model.setName(name);
                            list.add(model);
                        }
                    }
                }
            } else {

            }
        } catch (JSONException je) {
            Log.i(JSONParser.TAG, "" + je.getLocalizedMessage());
        }
        return null;
    }


    @Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);
        dialog.dismiss();

        //Checking if List size if more than zero then update ListView
        if(list.size() > 0) {
            adapter.notifyDataSetChanged();

        } else {
            Snackbar.make(findViewById(R.id.parentLayout), "No Data Found", Snackbar.LENGTH_LONG).show();
        }

    }
}
}

我在ArrayAdapter类中实现了filter方法。

这是我的ArrayAdapter类：

MyArrayAdapter.java

public class MyArrayAdapter extends ArrayAdapter<MyDataModel> implements Filterable{

List<MyDataModel> modelList;
Context context;
private LayoutInflater mInflater;
private ArrayList<MyDataModel> arrayList;

public MyArrayAdapter(Context context, List<MyDataModel> objects) {
    super(context, 0, objects);
    this.context = context;
    this.mInflater = LayoutInflater.from(context);
    modelList = objects;

    this.arrayList = new ArrayList<MyDataModel>();
    this.arrayList.addAll(modelList);
}

@Override
public MyDataModel getItem(int position) {
    return modelList.get(position);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    final ViewHolder vh;
    if (convertView == null) {
        View view = mInflater.inflate(R.layout.layout_row_view, parent, false);
        vh = ViewHolder.create((RelativeLayout) view);
        view.setTag(vh);
    } else {
        vh = (ViewHolder) convertView.getTag();
    }

    MyDataModel item = getItem(position);

    vh.textViewName.setText(item.getName());
    return vh.rootView;
}


private static class ViewHolder {
    public final RelativeLayout rootView;

    public final TextView textViewName;

    private ViewHolder(RelativeLayout rootView, TextView textViewName) {
        this.rootView = rootView;
        this.textViewName = textViewName;
    }

    public static ViewHolder create(RelativeLayout rootView) {
        TextView textViewName = (TextView) rootView.findViewById(R.id.textViewName);
        return new ViewHolder(rootView, textViewName);
    }
}

// Filter Class
public void filter(String charText) {
    charText = charText.toLowerCase(Locale.getDefault());
    modelList.clear();
    if (charText.length() == 0) {
        modelList.addAll(arrayList);
    } else {
        for (MyDataModel wp : arrayList) {
            if (wp.getName().toLowerCase(Locale.getDefault()).contains(charText)) {
                modelList.add(wp);
            }
        }
    }
    notifyDataSetChanged();
}

Answer 1

您需要再创建一个arryList来过滤数据。

public class MyArrayAdapter extends ArrayAdapter<MyDataModel> implements Filterable{

List<MyDataModel> modelList;
Context context;
private LayoutInflater mInflater;
private ArrayList<MyDataModel> arrayList;

public MyArrayAdapter(Context context, List<MyDataModel> objects) {
super(context, 0, objects);
this.context = context;
this.mInflater = LayoutInflater.from(context);
modelList = objects;
this.arrayList = new ArrayList<MyDataModel>();
    this.arraylist.addAll(modelList);
}

现在在Filter方法中，你必须在arrayList

的基础上进行比较

// Filter Class
 public void filter(String charText) {
 charText = charText.toLowerCase(Locale.getDefault());
 modelList.clear();
if (charText.length() == 0) {
    modelList.addAll(arrayList);
    } else {
    for (MyDataModel wp : arrayList) {
        if 
   (wp.getName().toLowerCase(Locale.getDefault()).contains(charText)) {
            modelList.add(wp);
        }
     }
    }
 notifyDataSetChanged();
}

TextChangedListener没有做任何事情

1 个答案: