Question

我尝试使用Custom ListView扩展BaseAdapter将数据库mysql中的数据显示到listview。数据库中的数据如：

tbl_userbook：

    id   | username  |  title          | category
   ------+-----------+-----------------+-------------
    1    | A         |  Java           | 1
    2    | B         |  VB.NET         | 1
    3    | C         |  Swing Java     | 1
    4    | D         |  Java Hibernate | 1
    5    | E         |  C#             | 1
    6    | F         |  Ruby           | 1
    7    | G         |  MySQL          | 1
    8    | H         |  Sqlite         | 1
    9    | I         |  PHP            | 1
    10   | J         |  MsSQL          | 1

我的问题是为什么列表视图显示从id 1到6开始的重复项目以及数据id 7,8,9,10未在列表视图中显示。

Listview显示的数据如：

    | username  |  title          | 
    +-----------+-----------------+
    | A         |  Java           |
    | B         |  VB.NET         |
    | C         |  Swing Java     |
    | D         |  Java Hibernate |
    | E         |  C#             |
    | F         |  Ruby           |
    | A         |  Java           | < ----  duplicate starting from here
    | B         |  VB.NET         |
    | C         |  Swing Java     |
    | D         |  Java Hibernate |

BaseAdapter：

public class HomeListViewAdapter extends BaseAdapter {

Context context;
ArrayList<HashMap<String, String>> userList;
HashMap<String, String> map = new HashMap<String, String>();

public HomeListViewAdapter(Context context,
        ArrayList<HashMap<String, String>> arraylist) {
    this.context = context;
    userList = arraylist;
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return userList.size();
}

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub

    TextView tvUsername, tvTitle;

    if (convertView == null) {
        LayoutInflater layoutInflator = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        convertView = layoutInflator.inflate(R.layout.custom_listview_home, parent, false);

        map = membersList.get(position);

        tvUsername = (TextView) convertView.findViewById(R.id.tvUsername);
        tvTitle = (TextView) convertView.findViewById(R.id.tvTitle);

        tvUsername.setText(map.get(FragmentHome.USERNAME));
        tvTitle.setText(map.get(FragmentHome.TITLE));

    }
    return convertView;

片段

public class FragmentHome extends SherlockFragment {

public static String USERNAME = "username";
public static String TITLE = "title";

private ProgressDialog pDialog; 
JSONPostGet jPostget = new JSONPostGet();
JSONArray users = null;
ArrayList<HashMap<String, String>> userList;

private static String url_getbook = "http://....../get_userbook.php";

ListView list;
HomeListViewAdapter homeadapter;

private static final String KEY_SUCCESS = "success";
private static final String KEY_USERS = "users";
private static final String KEY_USERNAME = "username";
private static final String KEY_TITLE = "title";

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_home, container, false);
    userList = new ArrayList<HashMap<String,String>>();
    new LoadUserBook().execute();
    return rootView;
}

class LoadUserBook extends AsyncTask<String, String, String> {

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
        pDialog = new ProgressDialog(getActivity());
        pDialog.setMessage("Please wait....");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }

    @Override
    protected String doInBackground(String... args) {
        // TODO Auto-generated method stub
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("category", "1"));
        JSONObject json = jPostget.makeHttpRequest(url_getbook, "GET", params);
        Log.d("All News Feed: ", json.toString());
        try {
            int success = json.getInt(KEY_SUCCESS);
            if (success == 1) {
                users = json.getJSONArray(KEY_USERS);
                for (int i = 0; i < users.length(); i++) {
                    JSONObject c = users.getJSONObject(i);

                    String suname = c.getString(KEY_USERNAME);
                    String stitle = c.getString(KEY_TITLE);

                    HashMap<String, String> map = new HashMap<String, String>();
                    map.put(KEY_USERNAME, suname);
                    map.put(KEY_TITLE, stitle);

                    userList.add(map);
                }
            } else {
                // ...
            }
        } catch (JSONException e) {
            // TODO: handle exception
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(String result) {
        // TODO Auto-generated method stub
        pDialog.dismiss();
        try {
            getActivity().runOnUiThread(new Runnable() {

                @Override
                public void run() {
                    // TODO Auto-generated method stub      
                    list = (ListView) getView().findViewById(R.id.listview1);
                    homeadapter = new HomeListViewAdapter(getActivity(), userList);
                    list.setAdapter(homeadapter);
                    homeadapter.notifyDataSetChanged();
                }
            });
        } catch (Exception e) {
            // TODO: handle exception
        }
    }
}

}

请帮忙。谢谢你提前

Answer 1

您的getView实施不正确。试试这个 -

  @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub

        TextView tvUsername, tvTitle;

        if (convertView == null) {
            LayoutInflater layoutInflator = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            convertView = layoutInflator.inflate(R.layout.custom_listview_home, parent, false);   
        }


            map = membersList.get(position);

            tvUsername = (TextView) convertView.findViewById(R.id.tvUsername);
            tvTitle = (TextView) convertView.findViewById(R.id.tvTitle);

            tvUsername.setText(map.get(FragmentHome.USERNAME));
            tvTitle.setText(map.get(FragmentHome.TITLE));

        return convertView;
}

Answer 2

我认为您没有将else添加到为convertView指定的条件为null。

所以现在你的代码只为那些当前正在显示的视图设置数据，对于剩余的数据，它重复先前已经初始化的视图。

试试这样，我相信你会得到解决方案：

if(convertView == null){
// some code here 
} 
else{
     holder = (ViewHolder) row.getTag();
}

Answer 3

我认为getItem（）应该返回userlist.get（position）和onCreateView
map = membersList.get（position）;
应该是 ap = userlist.get（position）;

另一件事是转换视图不为null时缺少else子句。

Answer 4

试试这个：

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub

    TextView tvUsername, tvTitle;

    if (convertView == null) {
        LayoutInflater layoutInflator = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        convertView = layoutInflator.inflate(R.layout.custom_listview_home, parent, false);




    }else{
       LayoutInflater layoutInflator = convertView;

    }

     map = membersList.get(position);

        tvUsername = (TextView) convertView.findViewById(R.id.tvUsername);
        tvTitle = (TextView) convertView.findViewById(R.id.tvTitle);

        tvUsername.setText(map.get(FragmentHome.USERNAME));
        tvTitle.setText(map.get(FragmentHome.TITLE));

    return convertView;
}

Answer 5

解决方案： -

您尚未正确实施Base适配器。 android出于性能原因回收视图，因此您需要初始化文本图像等。 everytime。所以你只需要将initiliazation代码放在convertview null检查之外。只需这样做： -

@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub

TextView tvUsername, tvTitle;

if (convertView == null) {
    LayoutInflater layoutInflator = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    convertView = layoutInflator.inflate(R.layout.custom_listview_home, parent, false);



    tvUsername = (TextView) convertView.findViewById(R.id.tvUsername);
    tvTitle = (TextView) convertView.findViewById(R.id.tvTitle);



}
map = membersList.get(position);
tvUsername.setText(map.get(FragmentHome.USERNAME));
    tvTitle.setText(map.get(FragmentHome.TITLE));
return convertView;
}

Answer 6

public View getView（int position，View view，ViewGroup parent）{ // TODO自动生成的方法存根

$("#hide").removeClass('hide');

检查此代码以了解何时回到父活动并通过.clear（）方法清除数据。我在我的应用程序及其工作中使用了此代码，因此您可以从此代码中了解如何管理列表视图中的重复条目

Answer 7

public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) context
        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View gridView;
    if (convertView == null) {
        gridView = new View(context);
    } else {
        gridView = (View) convertView;
    }
    gridView = inflater.inflate(R.layout.worker_listmain, null);
    // your source code here!!! Run 100%
    return gridView;
}

Answer 8

我认为您必须在活动类的清单文件中添加此行。机器人：windowSoftInputMode = “adjustPan”

使用BaseAdapter复制项自定义列表视图

8 个答案:

解决方案： -