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我有一個ListView，我已經做了一個自定義適配器綁定數據到它，我已經做了一個asynctask活動獲取數據並顯示它進入listView，我有兩個不同的Url爲同一個asyctask，根據我使用它的條件，事情是，當我第二次listView不會刪除以前的值。ListView中的舊數據仍然存在，當我將新值綁定到ListView中的android
main.java
public class MyMessagesActivity extends Activity {
private ProgressDialog pDialog;
JSONArray msgArry;
private MessageAdapter msgContent;
ArrayList<HashMap<String, String>> msgList;
ListView lv;
JSONArray msgs = null;
String pro_id, pro_name, pro_img, pro_unit;
TextView tv_switch;
public boolean flag = false;
Header header;
Menu menu;
String url;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_messgaes);
lv = (ListView) findViewById(R.id.list);
tv_switch = (TextView) findViewById(R.id.tv_switch);
header = (Header) findViewById(R.id.header_msg);
menu = (Menu) findViewById(R.id.menu_msg);
menu.setSelectedTab(3);
header.title.setText("Messages");
msgList = new ArrayList<HashMap<String, String>>();
// url = "?customer_id=" + Pref.getValue(MyMessagesActivity.this,
// Const.PREF_CUSTOMER_ID, "") + "&group_id=2";
tv_switch.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (flag) {
tv_switch.setText("Switch to supplier");
new GetMessages().execute();
flag = false;
} else {
tv_switch.setText("Switch to buyer");
new GetMessages().execute();
flag = true;
}
}
});
// AsyncTAsk for Wholesale Product List...!!!
new GetMessages().execute();
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// getting values from selected ListItem
// in = new Intent(getApplicationContext(),
// ProductDetailActivity.class);
/*
* pro_name = ((TextView)
* view.findViewById(R.id.product_label)).getText().toString();
*
* // getting ProductId from the tag...
*
* pro_id = msgList.get(position).get(Const.TAG_PRODUCT_ID);
* pro_name = msgList.get(position).get(Const.TAG_PRODUCT_NAME);
* pro_img = msgList.get(position).get(Const.TAG_PRODUCT_IMG);
* System.out.println(
* ":::::::::::::::;;THE INTENT FOR THE PRODUCUT DETIALS ACTIVITY================="
* + pro_name); Toast.makeText(MyMessagesActivity.this,
* pro_name, Toast.LENGTH_SHORT).show();
*/
// startActivity(in);
}
});
}
private class GetMessages extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(MyMessagesActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
BackendAPIService sh = new BackendAPIService();
String query = Const.API_MESSAGES;
if (flag) {
url = "?customer_id=" + Pref.getValue(MyMessagesActivity.this, Const.PREF_CUSTOMER_ID, "") + "&group_id=1";
} else {
url = "?customer_id=" + Pref.getValue(MyMessagesActivity.this, Const.PREF_CUSTOMER_ID, "") + "&group_id=2";
}
url = url.replace(" ", "%20");
url = query + url;
System.out.println(":::::::::::::My MESSGES URL::::::::::::::" + url);
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, BackendAPIService.GET);
Log.d("Response: ", "> " + jsonStr);
try {
if (jsonStr != null) {
msgArry = new JSONArray(jsonStr);
if (msgArry != null && msgArry.length() != 0) {
// looping through All Contacts
System.out.println(":::::::::::FLAG IN SUB:::::::::::" + msgArry.length());
for (int i = 0; i < msgArry.length(); i++) {
JSONObject c = msgArry.getJSONObject(i);
String custID = c.getString(Const.TAG_CUSTOMER_ID);
String custName = c.getString(Const.TAG_CUSTOMER_NAME);
String proID = c.getString(Const.TAG_PRODUCT_ID);
String email = c.getString(Const.TAG_CUSTOMER_EMAIL);
String photo = Const.API_HOST + "/" + c.getString(Const.TAG_PHOTO);
String subject = c.getString(Const.TAG_SUBJECT);
String msg_read = c.getString(Const.TAG_MESSAGE_READ);
HashMap<String, String> message = new HashMap<String, String>();
message.put(Const.TAG_CAT_ID, custID);
message.put(Const.TAG_CUSTOMER_NAME, custName);
message.put(Const.TAG_PRODUCT_ID, proID);
message.put(Const.TAG_CUSTOMER_EMAIL, email);
message.put(Const.TAG_PHOTO, photo);
message.put(Const.TAG_SUBJECT, subject);
message.put(Const.TAG_MESSAGE_READ, msg_read);
msgList.add(message);
}
} else {
runOnUiThread(new Runnable() {
@Override
public void run() {
Utils.showCustomeAlertValidation(MyMessagesActivity.this, "No messgaes found", "yehki", "Ok");
}
});
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
msgContent = new MessageAdapter(MyMessagesActivity.this, msgList);
msgContent.notifyDataSetChanged();
lv.setAdapter(msgContent);
}
}
}
請大家幫幫我吧，謝謝前夕，一個
當暫停狀態下的活動會清除數據，並且當任何對話框到達前臺時它可能處於暫停狀態，對話框是否不屬於Asynctask。所以總是必須在'onResume（）'中設置適配器 –