我是android的新手，我希望在数据插入mysql数据库时更新我的列表视图。我在互联网上搜索过，我使用过adapter.notifyDataSetChanged（）;但我一直收到错误＆＃34;方法notifyDataSetChanged（）未定义类型ListAdapter＆＃34;
代码：
public class Messages extends BaseActivity{
private String[] navMenuTitles;
private TypedArray navMenuIcons;
private EditText editTextName;
SharedPreferences sp;
private String jsonResult;
private ListView listView;
private Button b;
EditText etname, et;
TextView tv;
String myJSON;
private static final String TAG = "MainActivity.java";
private static final String TAG_RESULTS="result";
private static final String TAG_USERNAME = "username";
private static final String TAG_NAME = "message_recd";
private static final String TAG_ADD ="message_sent";
JSONArray peoples = null;
ArrayList<HashMap<String, String>> personList;
ListView list;
public static final String USER_NAME = "USERNAME";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_first);
SharedPreferences myprefs= getSharedPreferences("user", MODE_WORLD_READABLE);
String session_id= myprefs.getString("session_id", null);
TextView textView = (TextView) findViewById(R.id.fname);
textView.setText("Welcome "+session_id);
navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);
navMenuIcons = getResources().obtainTypedArray(R.array.nav_drawer_icons);
// load icons from
// strings.xml
set(navMenuTitles, navMenuIcons);
editTextName = (EditText) findViewById(R.id.editTextName);
b=(Button)findViewById(R.id.button1);
list = (ListView) findViewById(R.id.listView);
personList = new ArrayList<HashMap<String,String>>();
getData();
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
etname=(EditText)findViewById(R.id.editTextName);
if( etname.getText().toString().trim().equals("")){
etname.setError( "Cannot be left empty!" );
}
// TODO Auto-generated method stub
else{
Intent intent = getIntent();
String fName = intent.getStringExtra("fname");
String message = etname.getText().toString();
insertToDatabase(message, fName);
}
etname.setText("");
}
});
}
//send messages start
private void insertToDatabase(String message, String fName1){
class SendPostReqAsyncTask extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... params) {
String paramUsername = params[0];
String fname = params[1];
//InputStream is = null;
String message = editTextName.getText().toString();
Intent intent1 = getIntent();
String fName = intent1.getStringExtra("fname");
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair("message", message));
nameValuePairs.add(new BasicNameValuePair("username", fName));
try {
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost("http://10.0.2.2/test/test.php");
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpClient.execute(httpPost);
HttpEntity entity = response.getEntity();
//is = entity.getContent();
} catch (ClientProtocolException e) {
} catch (IOException e) {
}
return "success";
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
Toast.makeText(getApplicationContext(), result, Toast.LENGTH_LONG).show();
}
}
SendPostReqAsyncTask sendPostReqAsyncTask = new SendPostReqAsyncTask();
sendPostReqAsyncTask.execute(message, fName1);
}
//send messages stop
//get json data start
protected void showList(){
try {
JSONArray peoples = new JSONArray(myJSON);
for(int i=0;i<peoples.length();i++){
JSONObject c = peoples.getJSONObject(i);
String name=null, address=null;
if(c.has("message_recd"))
name = c.getString("message_recd");
else
address = c.getString("message_sent");
HashMap<String,String> persons = new HashMap<String,String>();
persons.put(TAG_NAME,name);
persons.put(TAG_ADD,address);
personList.add(persons);
}
/*ListAdapter adapter = new SimpleAdapter(
Messages.this, personList, R.layout.list_item,
new String[]{TAG_NAME,TAG_ADD},
new int[]{R.id.name, R.id.address}
);*/
ListAdapter adapter = new SimpleAdapter(
Messages.this, personList, R.layout.list_item,
new String[]{TAG_NAME,TAG_ADD},
new int[]{R.id.name, R.id.address}
);
// http://www.vogella.com/tutorials/AndroidListView/article.html
// http://stackoverflow.com/questions/8166497/custom-adapter-for-list-view
list.setAdapter(adapter);
} catch (JSONException e) {
Log.i("tagconvertstr", "["+myJSON+"]");
}
}
public void getData(){
class GetDataJSON extends AsyncTask<String, Void, String>{
@Override
protected String doInBackground(String... params) {
SharedPreferences myprefs= getSharedPreferences("user", MODE_WORLD_READABLE);
String session_id= myprefs.getString("session_id", null);
InputStream inputStream = null;
String result = null;
try {
String postReceiverUrl = "http://10.0.2.2/progress_card/messages/get_messages.php";
// HttpClient
HttpClient httpClient = new DefaultHttpClient();
// post header
HttpPost httpPost = new HttpPost(postReceiverUrl);
// add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("username", session_id));
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpClient.execute(httpPost);
HttpEntity resEntity = response.getEntity();
inputStream = resEntity.getContent();
// json is UTF-8 by default
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
result = sb.toString();
} catch (Exception e) {
Log.i("tagconvertstr", "["+result+"]");
System.out.println(e);
}
finally {
try{if(inputStream != null)inputStream.close();}catch(Exception squish){}
}
return result;
}
@Override
protected void onPostExecute(String result){
myJSON = result;
showList();
}
}
GetDataJSON g = new GetDataJSON();
g.execute();
}
//get json data stop
}
答案 0 :(得分：2)
notifyDataSetChanged方法是在BaseAdapter中定义和实现的，SimpleAdapter的超类型。所以只需添加一个转换为BaseAdapter或SimpleAdapter。
答案 1 :(得分：-1)
当您将任何add()或remove()操作执行到您的个人列表时，
调用adpater.notifyDataSetChanged();方法更新ListView