我正在开发一个基于套接字的应用程序。我需要从服务器套接字获取数据并每秒显示到listview。
我使用闹钟管理器从我的服务发送广播事件......
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
fireAlarm();
return START_NOT_STICKY;
}
public void fireAlarm() {
/**
* call broadcost reciver for AlarmReceiver
*/
//Intent intent = new Intent(AlarmService.this.getApplicationContext(), DefaultMarketWatch.class);
Intent intent=new Intent();
intent.setAction("com.pgi.eaxample");
pendingIntent = PendingIntent
.getBroadcast(AlarmService.this.getApplicationContext(), 0, intent,
PendingIntent.FLAG_UPDATE_CURRENT);
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
alarm = (AlarmManager) AlarmService.this.getApplicationContext()
.getSystemService(Context.ALARM_SERVICE);
alarm.cancel(pendingIntent);
alarm.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
1000, pendingIntent);
sendBroadcast(intent);
}
在活动中，我变得像
@Override
public void onReceive(Context context, Intent intent) {
new RetriveStock().execute();
}
} catch (Exception e) {
}
}
}
其中RetriveStock是异步任务。
public class RetriveStock extends AsyncTask<Void, Void, ArrayList<User>> {
@Override
protected ArrayList<User> doInBackground(Void... params) {
isCycleQuit=false;
JSONmessage += client.clientReceive(1);
message=JSONmessage;
JSONmessage="";
System.out.println("MESSAGE Socket::" + message);
return null;
}
@Override
protected void onCancelled() {
super.onCancelled();
}
protected void onPostExecute(ArrayList<User> result) {
if (!message.contains("null")) {
printJson();
// updateList();
displayView();
}
tasiDisplay();
if (message.contains("AlertStatus:")) {
String arrayMessage[] = message.split("AlertStatus:");
String arrayMessage2[] = arrayMessage[1].split(";");// AlertStatus:10,ALertCheck;
String arrayMessage3[] = arrayMessage2[0].split(",");
sqladapter.insertAlertStatus(arrayMessage3[1],
Integer.parseInt(arrayMessage3[0]));
// message = "AlertExecuted:" + arrayMessage3[0];
}
if (message.contains("AlertExecuted:")) {
progress.dismiss();
String arrayMessage[] = message.split("AlertExecuted:");// AlertExecuted:10;
String arrayMessage2[] = arrayMessage[1].split(";");
final String alertMessage = arrayMessage2[0];
if (sqladapter.checkAlertExist(Integer.parseInt(alertMessage)))
alertExecute.displayAlert(alertMessage,
DefaultMarketWatch.this);
message = message.replaceAll("AlertExecuted:", "");
}
listSetAdapter();
isCycleQuit=true;
super.onPostExecute(result);
}
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected void onProgressUpdate(Void... values) {
// mProgressDialog.setProgress(values[0]);
super.onProgressUpdate(values);
}
}
public void printJson() {
String str = "";
while (message.contains("{") && message.contains("}")) {
System.out.println("printJson::"+message);
try {
String splitString = message.substring(message.indexOf('{'),
message.indexOf('}') + 1);
for (int i = value; i < symbolList.size(); i++) {
String selectedSymbol = symbolList.get(i);
String cotes = "\"Id\":";
if (splitString.contains(cotes + selectedSymbol + ",")) {
try {
// JSONArray jsonArray = new JSONArray(str);
// for (int i = 0; i < jsonArray.length(); i++) {
JSONObject json = new JSONObject(splitString);
if (marketWatch.equalsIgnoreCase("custom"))
value = 0;
else
value = 1;
String symbol = json.getString("Symbol_En");
double high = Double.parseDouble(json
.getString("High"));
double low = Double.parseDouble(json
.getString("Low"));
User obj = new User();
boolean checkSymbol = false;
for (int j = 0; j < list.size(); j++) {
obj = list.get(j);
if (obj.getSymbol().equalsIgnoreCase(symbol)) {
checkSymbol = true;
break;
}
}
if (!checkSymbol) {
obj = new User();
obj.Symbol_En = json.getString("Symbol_En");
obj.Symbol_Ar = json.getString("Symbol_Ar");
obj.AskPrice = json.getString("Ask");
obj.BidPrice = json.getString("Bid");
obj.AskQuantity = json.getString("AskQuantity");
obj.High = high + "";
obj.Low = low + "";
obj.Open = json.getString("Open");
obj.Close = json.getString("Close");
obj.PerChange = json.getString("PerChange");
obj.NetChange = json.getString("NetChange");
obj.Volume = json.getString("Volume");
obj.Ltp = json.getString("LTP");
obj.TimeStamp = json.getString("TimeStamp");
obj.symbolId = json.getString("Id");
changePer = obj.PerChange;
netChange = obj.NetChange;
volume = obj.Volume;
open = obj.Open;
askQuality = obj.AskQuantity;
ltp = obj.Ltp;
if (obj.symbolId.equalsIgnoreCase("1001")) {
try {
String change;
double value;
String tasiValueSub[];
value = Double.parseDouble(changePer);
change = String.format("%.2f", value);
if (change.equalsIgnoreCase("0.00"))
tasi_perchange = "0";
else
tasi_perchange = change;
value = Double.parseDouble(netChange);
change = String.format("%.2f", value);
if (change.equalsIgnoreCase("0.00"))
tasi_netChange = "0";
else
tasi_netChange = change;
tasi_volume = addCamas(volume);
value = Double.parseDouble(open);
change = String.format("%.2f", value);
if (change.equalsIgnoreCase("0.00"))
tasi_index = "0";
else {
tasiValueSub = change.split("\\.");
tasiValueSub[0] = addCamas(tasiValueSub[0]);
tasi_index = tasiValueSub[0] + "."
+ tasiValueSub[1];
}
// tasi_index = change;
tasi_noOfTrads = addCamas(askQuality);
NumberFormat formatter = new DecimalFormat(
"#0.00");
tasi_value = formatter.format(Double
.parseDouble(ltp)) + "";
if (tasi_value.equalsIgnoreCase("0.00"))
tasi_value = "0";
else {
tasiValueSub = tasi_value
.split("\\.");
tasiValueSub[0] = addCamas(tasiValueSub[0]);
tasi_value = tasiValueSub[0] + "."
+ tasiValueSub[1];
}
} catch (NumberFormatException e) {
e.printStackTrace();
} catch (IllegalStateException e) {
}
} else {
list.add(obj);
}
} else {
obj.Symbol_En = json.getString("Symbol_En");
obj.AskPrice = json.getString("Ask");
obj.BidPrice = json.getString("Bid");
obj.High = high + "";
obj.Low = low + "";
obj.Open = json.getString("Open");
obj.Close = json.getString("Close");
obj.PerChange = json.getString("PerChange");
obj.NetChange = json.getString("NetChange");
obj.Volume = json.getString("Volume");
obj.Ltp = json.getString("LTP");
obj.TimeStamp = json.getString("TimeStamp");
obj.symbolId = json.getString("Id");
changePer = obj.PerChange;
netChange = obj.NetChange;
volume = obj.Open;
open = obj.Open;
askQuality = obj.AskQuantity;
ltp = obj.Ltp;
}
// }
} catch (JSONException e1) {
// ////System.out.println("///////////////////////"
// +
// e1);
log.createFile(str);
e1.printStackTrace();
} catch (NumberFormatException e) {
log.createFile(str);
e.printStackTrace();
} catch (IllegalStateException e) {
log.createFile(str);
e.printStackTrace();
}
// str = str + splitString;
}
}
if(message.indexOf('}')>0){
message = message.substring(message.indexOf('}') + 1);
}
} catch (StringIndexOutOfBoundsException e) {
String errMsg = e.getClass().getName() + " " + e.getMessage();
log.createFile("Error in printJson" + errMsg + "\n");
e.printStackTrace();
} catch (Exception e) {
String errMsg = e.getClass().getName() + " " + e.getMessage();
log.createFile("Error in printJson" + errMsg + "\n");
e.printStackTrace();
}
}
// ////System.out.println("Message:" + message);
// message = str;
// if (!str.equalsIgnoreCase("")) {
// str = str.replace("}", "},");
// if ((str.charAt(str.length() - 1) == ',')) {
// str = str.substring(0, str.length() - 1);
//
// }
// }
// str = "[" + str + "]";
// ////System.out.println("STR VALUE:" + str);
}
我正在读取数据并在第一次创建活动时显示到listview。 当我导航到其他屏幕时，在旧屏幕中完成之前的异步任务之前，UI不会更新。
我希望在导航到新屏幕之前/之后终止所有异步任务。如何杀死所有异步任务。
请帮忙， 感谢!!!
答案 0 :(得分：0)
将Async任务存储在数组中。并在需要时停止：
//Array of task
ArrayList<AsyncTask> asyntask= new ArrayList<>();
//Add task to your array
asyntask.add(new RetriveStock().execute());
//Stop task
for (RetriveStock task : asyntask){
task.cancel(true);
}
答案 1 :(得分：0)
您应该通过isCancelled()方法调用doInBackground来定期检查任务是否已取消。要定期检查，您必须在doInBackground中使用循环。
@Override
protected ArrayList<User> doInBackground(Void... params) {
while(clientHasNext()) { // I just made it up
if(isCancelled()) {
return null;
}
isCycleQuit=false;
JSONmessage += client.clientReceive(1);
message=JSONmessage;
JSONmessage="";
System.out.println("MESSAGE Socket::" + message);
}
return null;
}