Question

我正在尝试使用顶部的编辑文本过滤列表视图，但它在添加文本更改的侦听器的adapter2.filter（文本）中提供空指针异常。请给我一些建议。

这是我的编辑文字

friendsList.setAdapter(new FriendListAdapter(this));

    search.addTextChangedListener(new TextWatcher() {

        @Override
        public void afterTextChanged(Editable arg0) {
            // TODO Auto-generated method stub

            String text = search.getText().toString().toLowerCase(Locale.getDefault());
            System.out.println("test=="+text);
            adapter2.filter(text);
        }

        @Override
        public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
            // TODO Auto-generated method stub
            //adapter.getFilter().filter(arg0.toString());

        }

        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                int arg3) {
            // TODO Auto-generated method stub

        }


    });

这是我的适配器

public class FriendListAdapter extends BaseAdapter {

    private LayoutInflater mInflater;

    FriendsList friendsList;
    Context context;
    ViewHolder holder;
    private boolean userSelected = false;
    private RadioButton mCurrentlyCheckedRB;

    private int mResourceId = 0;
    private LayoutInflater mLayoutInflater; 
    private RadioButton mSelectedRB;
    private int mSelectedPosition = -1;

    public FriendListAdapter(FriendsList friendsList) {
        this.friendsList = friendsList;
        if (Utility.model == null) {
            Utility.model = new FriendsGetProfilePics();
        }
        Utility.model.setListener(this);
        mInflater = LayoutInflater.from(friendsList.getBaseContext());
    }

    @Override
    public int getCount() {
        return jsonArray.length();
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int arg0) {
        return 0;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup viewgroup) {
        JSONObject jsonObject = null;
        Model model = (Model) getItem(position);
        try {
            jsonObject = jsonArray.getJSONObject(position);
        } catch (JSONException e1) {
            e1.printStackTrace();
        }
        View hView = convertView;
        if (convertView == null) {
            hView = mInflater.inflate(R.layout.friend_item, null);
            ViewHolder holder = new ViewHolder();
            holder.profile_pic = (ImageView) hView
                    .findViewById(R.id.profile_pic);
            holder.name = (TextView) hView.findViewById(R.id.name);
            holder.info = (TextView) hView.findViewById(R.id.info);
            holder.radiobt = (RadioButton) hView.findViewById(R.id.radio);
            hView.setTag(holder);
        }
        ViewHolder holder = (ViewHolder) hView.getTag();
        if (position == getCount() - 1 && userSelected == false) {
            holder.radiobt.setChecked(true);
            mCurrentlyCheckedRB = holder.radiobt;
        } else {
            holder.radiobt.setChecked(false);
        }

        holder.radiobt.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub



                if((position != mSelectedPosition && mSelectedRB != null)){
                    mSelectedRB.setChecked(false);
                }

                mSelectedPosition = position;
                mSelectedRB = (RadioButton)v;


                System.out.println("onItemClick ");
                try {

                    if (graph_or_fql.equals("graph")) {

                        System.out.println("in if loop ");
                        friendId = jsonArray.getJSONObject(position).getLong("id");
                        image = jsonArray.getJSONObject(position).getString("picture");
                        // sb.append(friendId).append(",");
                        freind_id = String.valueOf(friendId);

                    } else {

                        System.out.println("in else loop ");
                        friendId = jsonArray.getJSONObject(position).getLong("uid");
                        image = jsonArray.getJSONObject(position).getString(
                                "pic_square");
                        // sb.append(friendId).append(",");
                        freind_id = String.valueOf(friendId);
                    }
                    check = true;
                    name = jsonArray.getJSONObject(position).getString("name");

                    Toast.makeText(getApplicationContext(), "You Selected : " + name,
                            Toast.LENGTH_SHORT).show();

                } catch (JSONException e) {
                    e.printStackTrace();
                    e.getMessage();
                }



            }
        });


        if(mSelectedPosition != position){
            holder.radiobt.setChecked(false);
        }else{
            holder.radiobt.setChecked(true);
            if(mSelectedRB != null && holder.radiobt != mSelectedRB){
                mSelectedRB = holder.radiobt;
            }
        }

    try {
            if (graph_or_fql.equals("graph")) {
                holder.profile_pic.setImageBitmap(Utility.model.getImage(
                        jsonObject.getString("id"),
                        jsonObject.getString("picture")));
            } else {
                holder.profile_pic.setImageBitmap(Utility.model.getImage(
                        jsonObject.getString("uid"),
                        jsonObject.getString("pic_square")));
            }
        } catch (JSONException e) {
            holder.name.setText("");
        }
        try {
            holder.name.setText(jsonObject.getString("name"));
        } catch (JSONException e) {
            holder.name.setText("");
        }
        try {
            if (graph_or_fql.equals("graph")) {
                holder.info.setText(jsonObject.getJSONObject("location")
                        .getString("name"));
            } else {
                JSONObject location = jsonObject
                        .getJSONObject("current_location");
                holder.info.setText(location.getString("city") + ", "
                        + location.getString("state"));
            }

        } catch (JSONException e) {
            holder.info.setText("");
        }
        return hView;

    }


    // Filter Class
    public void filter(String charText) {
        System.out.println("in adapter filter");
        charText = charText.toLowerCase(Locale.getDefault());
        System.out.println("1");
        rowitems.clear();
        System.out.println("2");

        if (charText.length() == 0) {
            System.out.println("3");
            rowitems.addAll(listData);
        } else {
            for (Model wp : listData) {
                if (wp.getName().toLowerCase(Locale.getDefault())
                        .contains(charText)) {
                    rowitems.add(wp);
                }
            }
        }
        notifyDataSetChanged();
    }


    private class ViewHolder {
        ImageView profile_pic;
        TextView name;
        TextView info;
        // CheckBox check;
        RadioButton radiobt;
    }       
}

这是我的主要活动

public class FriendsList extends Activity implements OnItemClickListener{

private Handler mHandler;
public static Long friendId;
public static String name = "";
protected ListView friendsList;
protected static JSONArray jsonArray;
protected String graph_or_fql;
public Button bt;
public static String image = "0";
public boolean check = false;
public static String freind_id = "";
public boolean select = false;
public RadioButton radiobtn;    

public ListView friendList; 
private List<Model> rowitems=null;
ArrayList<Model> listData;
    AdapterList adapter;
    EditText search;

FriendListAdapter adapter2;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mHandler = new Handler();
    setContentView(R.layout.friends_list);
    //radioSexGroup = (RadioGroup) findViewById(R.id.radioSex);
    bt = (Button) findViewById(R.id.com_facebook_picker_done_button);
    radiobtn = (RadioButton) findViewById(R.id.radio);

    search=(EditText) findViewById(R.id.editText100);

    Bundle extras = getIntent().getExtras();
    String apiResponse = extras.getString("API_RESPONSE");
    graph_or_fql = extras.getString("METHOD");
    try {
        if (graph_or_fql.equals("graph")) {
            jsonArray = new JSONObject(apiResponse).getJSONArray("data");
        } else {
            jsonArray = new JSONArray(apiResponse);
        }
    } catch (JSONException e) {
        e.printStackTrace();
        e.getMessage();
        return;
    }
    friendsList = (ListView) findViewById(R.id.friends_list);

//  friendsList.setAdapter(new FriendListAdapter(this));

    adapter2=new FriendListAdapter(this);
    friendsList.setAdapter(adapter2);

    friendsList.setOnItemClickListener(this);

    search.addTextChangedListener(new TextWatcher() {

        @Override
        public void afterTextChanged(Editable arg0) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
            // TODO Auto-generated method stub

              adapter2.getFilter().filter(arg0.toString());
        }

        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                int arg3) {
            // TODO Auto-generated method stub

        }
    });

我将facebook好友列表传递给listview.please提供了一些建议提前致谢

Answer 1

使用顶部的编辑文本过滤列表视图。我用过这段代码。制作一个名为searchResults的列表，而不是onTextChanged edittext方法，只需执行此操作 -

String searchString = `your edittext object`.getText().toString();
int textLength = searchString.length();
searchResults.clear();
for (int i = 0; i < `your main list of items`.size(); i++) {
String name = `your main list of items`.get(i).get("`your key`").toString();
System.out.println(" name " + name);
if (textLength <= title.length()) {
// compare the String in EditText with Names in the
// ArrayList
if (searchString.equalsIgnoreCase(name.substring(0, textLength))) {
    searchResults.add(`your main list of items`.get(i));
    System.out.println("the array list is "+ `your main list of items`.get(i));
    mAdapter = new Adapter(this, searchResults);
    `your ListView object`.setAdapter(mAdapter);
    }
     }
  }
  if (searchResults.isEmpty()) {
  Toast toast = Toast.makeText(getApplicationContext(),"No Items Matched",Toast.LENGTH_SHORT);
  toast.show();
  mAdapter = new Adapter(this, searchResults);
    `your ListView object`.setAdapter(mAdapter);
 }
  mAdapter.notifyDataSetChanged();

并在setOnItemClickListener上检查searchResults.isEmpty()是否为真，而不是使用your main list of items，如果错误则使用searchResults列表。可能它会帮助你。这个。

Answer 2

使用以下代码更改过滤器：

@Override
public Filter getFilter() {
    //Log.d("in filter", "yes");
    return new Filter() {
          @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                final FilterResults oReturn = new FilterResults();

并在此功能中设置列表，然后设置列表：

    oReturn.values = YourList;

和finall

    return oReturn;

并在search.addTextChangedListener(new TextWatcher())中的onTextChanged添加以下行：

    adapter2.getFilter().filter(s.toString());

Answer 3

试试这个，

adapter2=new FriendListAdapter(this);
friendsList.setAdapter(adapter2);

带有过滤器的Listview

3 个答案: