How can I start AsyncTask's doInBackground repeatedly when I start the 'A activity'? [complete] - android-asynctask

Question

I make the HttpURLConnection to get data from MySQL (android+jsp+MySQL) in my android's AsyncTask.
when I start 'A activity', the first is OK. I can start doInBackground. but when I start the 'A activity' next, I can't start doInBackgound when I start 'A activity' repeatedly.
I want to start doInBackground whenever I start the 'A activity' repeatedly.
because I get data from MySQL in doInBackground.
I used to "task.cancel(true)" but this not working.
I'm nuwbe in android, please tell me how to start doInBackground repeatedly.
thank advance.
behind is my code.
oncreate code
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_confirm_inventory);
...........
connectJSP = new getInventoryFromMySQL();
connectJSP.execute();
...........
}
onBackPressed code
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.END)) {
drawer.closeDrawer(GravityCompat.END);
} else {
connectJSP.cancel(true);
super.onBackPressed();
}
}
AsyncTask code
private class getInventoryFromMySQL extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... sId) {
String sResult = "Error";
try {
//URL setting and access
URL url = new URL("http://-----.com/*****.jsp");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
//setting
conn.setRequestMethod("POST");
// connection values
String sendBicycleName = bicycleName;
String sendBicycleYear = bicycleYear;
//StringBuffer
StringBuffer buffer = new StringBuffer();
buffer.append("sendBicycleName").append("=").append(sendBicycleName).append("&");
buffer.append("sendBicycleYear").append("=").append(sendBicycleYear);
//put data into JSP
OutputStreamWriter osw = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
osw.write(buffer.toString());
osw.flush();
//get data from JSP
InputStreamReader tmp = new InputStreamReader(conn.getInputStream(), "UTF-8");
BufferedReader reader = new BufferedReader(tmp);
String str;
//fit the order with JSP(garbage values)
reader.readLine(); reader.readLine(); reader.readLine(); reader.readLine();
//get data from JSP
for(;;) {
if((str = reader.readLine()) != null && (str != "") && (str != " ") && (str != "null")) {
mysqlStoreId[countInventory] = str;
for(int c=0; c<5; c++) {
for(int s=0; s<8; s++) {
str = reader.readLine();
mysqlInventory[countInventory][c][s] = Integer.parseInt(str);
}
}
countInventory++;
} else if(str == null && str == "null") {
//finish for if values equals null
break;
}
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return sResult;
}
}

Answer 1

I find the answer. I check all code's log.
the problem is that 'doInBackground' have an error. there is no an else in 'for(;;)' so AsyncTack make 'onCancelled()'. but I'm not write the 'onCancelled()' code.
when I add onCancelled(), I can cancel(true) and re-start the Asynctask.
Thank!