显示来自Hashmap的Arraylist的数据

Question

我正在获取json数据并将其放入hashmap和hashmap到arraylist中。所有这些都发生在片段扩展ListFragment

中

  protected String doInBackground(String... urls) {
         JSONObject jsonObject = new JSONObject();

        try {

            jsonObject.put("full_name", etUserSearch.getText().toString());
            responseReceive = JsonPostClient.SendHttpPost(urls[0],
                    jsonObject);

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

        try {
            Success = responseReceive.getJSONArray("Success");

            for (int i = 0; i < Success.length(); i++) {
                JSONObject c = Success.getJSONObject(i);

                String full_name = c.getString(TAG_FULL_NAME);
                String user_name = c.getString(TAG_USER_NAME);
                String user_id = c.getString(TAG_USER_ID);

                HashMap<String, String> friends = new HashMap<String, String>();

                // adding each child node to HashMap key => value
                friends.put(TAG_FULL_NAME, full_name);
                friends.put(TAG_USER_NAME, user_name);
                friends.put(TAG_USER_ID, user_id);

                // adding contact to contact list
                FriendSearchList.add(friends);

            }
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            Log.d("hello", "");
            e.printStackTrace();
        }

        return null;
    }

    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        if (pDialog.isShowing())
            pDialog.dismiss();
        printFriends();
    };

我通过printFriends（）方法检查数据是否有效，并且只想显示＆＃39; TAG_FULL_NAME＆＃39;列表视图中的数据。我的ListView初始化

    View rootView = inflater.inflate(R.layout.tab_add_friends, container,
            false);
    lv = (ListView) rootView.findViewById(R.id.listView);

在ListView中检查数据和加载的方法

 public void printFriends() {
    int len = FriendSearchList.size();

    for (int i = 0; i < len; i++) {
        String f_name = FriendSearchList.get(i).get(TAG_FULL_NAME);
        String u_name = FriendSearchList.get(i).get(TAG_USER_NAME);
        String u_id = FriendSearchList.get(i).get(TAG_USER_ID);

        Log.d("full_name", f_name);
        Log.d("user_name", u_name);
        Log.d("user_id", u_id);
    }


    ListAdapter adapter = new SimpleAdapter(getActivity(),
            FriendSearchList, R.layout.tab_addfriend_list,
            new String[] { TAG_FULL_NAME }, new int[] { R.id.full_name });

    setListAdapter(adapter);

}

tab_add_friends xml layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ListView
       android:id="@android:id/list"
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"/>

</LinearLayout>

tab_addfriend_list xml layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="10dp"
    android:paddingLeft="10dp"
    android:paddingRight="10dp" >

<!-- Name Label -->

   <TextView
       android:id="@+id/full_name"
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:paddingBottom="2dip"
       android:paddingTop="6dip"
       android:textColor="#43bd00"
       android:textSize="16sp"
       android:textStyle="bold" />


</LinearLayout>

没有错误显示列表视图中没有显示任何内容。需要建议或线索来摆脱这个问题。

Answer 1

问题是你传递的是HashMap的Arraylist，其中SimpleAdapter不知道哪些数据要放在ListView项目的布局中。

您可以使用它来实现ListView

中的项目

<强>样品：

ListAdapter adapter = new SimpleAdapter(getActivity(),
                                            FriendSearchList, R.layout.tab_addfriend_list,
                                            new String[] { TAG_FULL_NAME }, new int[] { R.id.full_name }){
        @Override
        public int getCount() {
            return FriendSearchList.size();
        }
        @Override
        public View getView(int position,View convertView,ViewGroup parent) {
            View v;
            if(convertView == null)
            {
                v = getActivity().getLayoutInflater().inflate(R.layout.tab_addfriend_list, parent);
                TextView tx = (TextView) v.findViewById(R.id.full_name);
                tx.setText(FriendSearchList.get(i).get(TAG_FULL_NAME));
            } else 
                v = convertView;

            return v;
        }
    };

Answer 2

我有一次同样的问题 问题是你使用简单的适配器提供数据，但是你可能会在ui线程之外给rowView充气并从post执行中提供。这就是为什么你的观点没有得到数据。实际上你不必在这里给行视图充气就是你的漏洞代码。另外一个print friend方法也没用，只是在onPostExecute（）方法中初始化简单的适配器。

`public class MainActivity扩展了ListActivity {

private ProgressDialog pDialog;


// URL to get contacts JSON
private static String url = "http://api.androidhive.info/contacts/";

// JSON Node names
private static final String TAG_CONTACTS = "contacts";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
private static final String TAG_ADDRESS = "address";
private static final String TAG_GENDER = "gender";
private static final String TAG_PHONE = "phone";
private static final String TAG_PHONE_MOBILE = "mobile";
private static final String TAG_PHONE_HOME = "home";
private static final String TAG_PHONE_OFFICE = "office";


private boolean isConnection = false;

// contacts JSONArray
JSONArray contacts = null;

// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList;

ArrayList<HashMap<String, String>> oflineContactList;

private MyContactDataSource dataSource;

List<Contatcs> oflineContatcs;

// private ListAdapter adapter1;

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



    dataSource = new MyContactDataSource(MainActivity.this); 
    dataSource.open();




    contactList = new ArrayList<HashMap<String,String>>();



    oflineContactList = dataSource.getContatcs();


    Log.i("data", oflineContactList.toString());
        ListView lv = getListView();

        ListAdapter adapter = new SimpleAdapter(
                MainActivity.this, oflineContactList,
                R.layout.list_item, new String[] { TAG_NAME, TAG_EMAIL,
                        TAG_PHONE_MOBILE }, new int[] { R.id.email,
                        R.id.name, R.id.mobile });

        setListAdapter(adapter);




    lv.setOnItemClickListener(new OnItemClickListener() {



        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // getting values from selected ListItem
            String name = ((TextView) arg1.findViewById(R.id.name))
                    .getText().toString();
            String cost = ((TextView) arg1.findViewById(R.id.email))
                    .getText().toString();
            String description = ((TextView) arg1.findViewById(R.id.mobile))
                    .getText().toString();

            // Starting single contact activity
            Intent intent = new Intent(MainActivity.this, SingleListItemActivity.class);
            intent.putExtra(TAG_NAME, name);
            intent.putExtra(TAG_EMAIL, cost);
            intent.putExtra(TAG_PHONE_MOBILE, description);

            startActivity(intent);

        }
    });

    new GetContacts().execute();


}



private class GetContacts extends AsyncTask<Void, Void, Void>{

    @Override
    protected void onPreExecute() {

        super.onPreExecute();
        pDialog = new ProgressDialog(MainActivity.this);
        pDialog.setMessage("Data is loading...please wait...");
        pDialog.setCancelable(false);
        pDialog.show();
    }


    @Override
    protected Void doInBackground(Void... params) {
        // Creating service handler class instance
        ServiceHandler mHandler = new ServiceHandler();


        // Making a request to url and getting response
        String jsonStr = mHandler.makeServiceCall(url, ServiceHandler.GET);

         Log.d("Response: ", "> " + jsonStr);

         if(jsonStr != null){
            try {
                JSONObject jsonObject = new JSONObject(jsonStr);

                //Getting JSON Array node
                contacts = jsonObject.getJSONArray(TAG_CONTACTS);

                // looping through All Contacts
                for (int i = 0; i < contacts.length(); i++) {
                    JSONObject c = contacts.getJSONObject(i);

                    String id = c.getString(TAG_ID);
                    String name = c.getString(TAG_NAME);
                    String email = c.getString(TAG_EMAIL);
                    String address = c.getString(TAG_ADDRESS);
                    String gender = c.getString(TAG_GENDER);

                 // Phone node is JSON Object
                    JSONObject phone = c.getJSONObject(TAG_PHONE);
                    String mobile = phone.getString(TAG_PHONE_MOBILE);
                    String home = phone.getString(TAG_PHONE_HOME);
                    String office = phone.getString(TAG_PHONE_OFFICE);


                 // tmp hashmap for single contact
                    HashMap<String, String> contact = new HashMap<String, String>();

                 // adding each child node to HashMap key => value
                    contact.put(TAG_ID, id);
                    contact.put(TAG_NAME, name);
                    contact.put(TAG_EMAIL, email);
                    contact.put(TAG_PHONE_MOBILE, mobile);

                 // adding contact to contact list
                    contactList.add(contact);

                }
                dataSource.creareContacts(contactList);
                dataSource.close();
            } catch (JSONException e) {
                e.printStackTrace();
            }


         }
         else {
             Log.e("ServiceHandler", "Couldn't get any data from the url");
        }
        return null;
    }


    @Override
    protected void onPostExecute(Void result) {

        super.onPostExecute(result);

        // Dismiss the progress dialog
        if(pDialog.isShowing()){
            pDialog.dismiss();
        }

         /**
         * Updating parsed JSON data into ListView
         * */
         ListAdapter adapter = new SimpleAdapter(
                 MainActivity.this, contactList,
                    R.layout.list_item, new String[] { TAG_NAME, TAG_EMAIL,
                            TAG_PHONE_MOBILE }, new int[] { R.id.name,
                            R.id.email, R.id.mobile });

         setListAdapter(adapter);
    }
}

}`