我想通过从后台服务收到新数据来更新我的ChatMessageAdapter，以便我想从后台调用UpdateAdapter方法来更新适配器。
这是我的ServiceClass：
public class MyService extends Service{
private String loginUserInfoId;
SessionManager session;
DatabaseHelper db;
MessageListActivity mLA;
long totalSize = 0;
@Override
public void onCreate() {
super.onCreate();
}
@Override
public void onDestroy() {
super.onDestroy();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
db = new DatabaseHelper(getApplicationContext());
mLA = new MessageListActivity();
session = new SessionManager(getApplicationContext());
session.checkLogin();
HashMap<String, String> user = session.getUserDetails();
loginUserInfoId = user.get(SessionManager.KEY_USER_INFO_ID);
if(isInternetOn()) {
new syncMessageFromServer().execute();
new SyncPendingMessageToServer();
}
return super.onStartCommand(intent, flags, startId);
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
private class syncMessageFromServer extends AsyncTask<Void, Integer, String> {
@Override
protected void onPreExecute() {
// setting progress bar to zero
//progressBar.setProgress(0);
super.onPreExecute();
}
@Override
protected void onProgressUpdate(Integer... progress) {
}
@Override
protected String doInBackground(Void... params) {
return uploadFile();
}
@SuppressWarnings("deprecation")
private String uploadFile() {
String str = "";
HttpResponse response;
HttpClient myClient = new DefaultHttpClient();
HttpPost myConnection = new HttpPost("http://192.168.1.2/AndroidApp/GetAllMessage/" + loginUserInfoId);
try {
response = myClient.execute(myConnection);
str = EntityUtils.toString(response.getEntity(), "UTF-8");
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
JSONArray jArray = new JSONArray(str);
for (int i = 0; i <= jArray.length() - 1; i++) {
JSONObject row = jArray.getJSONObject(i);
ChatMessage cm = new ChatMessage();
String offlineFileURL = "";
/******* Firstly take data in model object ******/
cm.setOriginalMsgThreadId(row.getString("MessageThreadId"));
cm.setSenderUserInfoId(row.getString("SenderUserId")); cm.setReceiverUserInfoId(row.getString("MultipleReceiversId"));
cm.setMessageStatus("SENT");
cm.setIsPending(0);
cm.setMessageText(row.getString("MessageText"));
cm.setMediaURL(offlineFileURL);
cm.setThumbImage(offlineFileURL);
cm.setMediaMIMEType("");
cm.setMediaSize(0);
cm.setMediaName("");
cm.setLatitude("");
cm.setLongitude("");
cm.setSendTimeStamp(row.getString("SendTime"));
cm.setReceiveTimeStamp(row.getString("ReadTime"));
mLA.UpdateAdapter(ChatMessage cm);
long messageThreadId = db.SendMessage(cm);
}
} catch (JSONException e) {
e.printStackTrace();
}
return str;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if(isInternetOn()) {
new syncMessageFromServer().execute();
}
}
}
}
这是我的MessageActivityList类：
public class MessageListActivity extends ActionBarActivity {
private String receiverUserInfoId;
private String loginUserInfoId;
private String orgMsgThreadId;
private String userName;
private String uploadedFileURL = "";
DatabaseHelper db;
SessionManager session;
private ChatMessageAdapter chatMessageAdapter;
private EditText chatText;
private ImageButton buttonSend;
private ListView listView;
private static final String TAG = MessageListActivity.class.getSimpleName();
// Camera activity request codes
private static final int CAMERA_CAPTURE_IMAGE_REQUEST_CODE = 100;
private static final int CAMERA_CAPTURE_VIDEO_REQUEST_CODE = 200;
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
private Uri fileUri; // file url to store image/video
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_message_list);
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
.detectAll()
.penaltyLog()
.build());
StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder().detectAll()
.penaltyLog()
.build());
db = new DatabaseHelper(getApplicationContext());
session = new SessionManager(getApplicationContext());
session.checkLogin();
HashMap<String, String> user = session.getUserDetails();
loginUserInfoId = user.get(SessionManager.KEY_USER_INFO_ID);
Intent intent=getIntent();
Bundle extra = intent.getExtras();
receiverUserInfoId=extra.getString("UserInfoId");
orgMsgThreadId = extra.getString("OrgMessageThreadId");
userName=extra.getString("UserName");
setTitle(userName);
listView = (ListView) findViewById(R.id.messageList);
chatMessageAdapter = new ChatMessageAdapter(getApplicationContext(), R.layout.activity_single_message);
listView.setAdapter(chatMessageAdapter);
buttonSend = (ImageButton) findViewById(R.id.buttonSend);
chatText = (EditText) findViewById(R.id.chatText);
chatText.setOnKeyListener(new View.OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {
if(chatText.getText().toString().trim().length() > 0){
sendChatMessage();
}
}
return false;
}
});
buttonSend.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
sendChatMessage();
}
});
listView.setTranscriptMode(AbsListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
// listView.setAdapter(chatMessageAdapter);
//to scroll the list view to bottom on data change
chatMessageAdapter.registerDataSetObserver(new DataSetObserver() {
@Override
public void onChanged() {
super.onChanged();
listView.setSelection(chatMessageAdapter.getCount() - 1);
}
});
setListData();
}
public void UpdateAdapter(ChatMessage cm) {
chatMessageAdapter.add(cm);
}
}
如何调用此UpdateAdapter方法来更新服务器收到的ChatMessage？
答案 0 :(得分：0)
您应该使用LocalBroadcastReceiver。
注册接收onResume中的更新并在onPause中取消注册。
答案 1 :(得分：0)
您可以使用广播接收器从服务更新UI。
在你的活动的onCreate（）中注册广播接收器：
private UpdateReceiver updateReceiver;
if (UpdateReceiver == null)
{
updateReceiver = new UpdateReceiver();
IntentFilter intentFilter = new
IntentFilter("REFRESH_DATA");
registerReceiver(updateReceiver, intentFilter);
}
取消注册你的活动
的onDestroy（）if (updateReceiver != null) unregisterReceiver(updateReceiver);
在你的活动中定义广播接收器：
private class UpdateReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("REFRESH_DATA")) {
//update adapter from here
}
}
}
在您希望更新适配器的情况下，请调用sendBroadcast。像：
Intent intent=new Intent("REFRESH_DATA");
//u can pass the data through putExtras
sendBroadcast(intent);
答案 2 :(得分：0)
使用广播接收器从服务更新UI并在你要接收的主要活动的onCreate（）中注册广播接收器
代码将在下面
private UpdateReceiver updateReceiver;
if (UpdateReceiver == null)
{
updateReceiver = new UpdateReceiver();
IntentFilter intentFilter = new
IntentFilter("REFRESH_DATA");
registerReceiver(updateReceiver, intentFilter);
}
并创建类以检查更新是否已收到
private class UpdateReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("REFRESH_DATA")) {
//update adapter from here
}
}
}
答案 3 :(得分：-1)
在您的活动中注册BroadcastReceiver。在此接收器的onReceive方法中调用该方法。从您的Service sendBroadcast到此接收器，请记住将所需数据添加到您的意图中，并从onReceive方法意图中获取数据。