How to kill NSThread while clicking on new tab iOS? - ios

Question

I building an app has 4 tab (Tabbar Controller), and each tab I call a function (updateArray) after 2s. I want to when click on other tab, updateArray() function is kill. My problem is when on tab, updateArray() call after 2s, when I click on other tab, this function is still call.
This is updateArray()
-(void)updateArray{
while (loop)
{
[NSThread sleepForTimeInterval:2.0];
[FileCompletedArray removeAllObjects];
[temp removeAllObjects];
[UserNameArray removeAllObjects];
NSURL *url1 = [NSURL URLWithString:#"server"];
AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL: url1] ;
NSMutableURLRequest *afRequest = [httpClient requestWithMethod:#"POST" path:nil parameters:params1] ;
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:afRequest];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(#"Success");
NSString * parsexmlinput = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
NSLog(#"Response in Loop CompleteView: %#", parsexmlinput); //000400010001
// dispatch_async(dispatch_get_main_queue(), ^{
[self parseXMLFile:parsexmlinput];
NSLog(#"File Completed array: %#", FileCompletedArray);
NSLog(#"File Temp out array: %#", temp);
NSLog(#"File Completed count: %lu",(unsigned long)[ FileCompletedArray count]);
NSLog(#"File Temp out count: %lu", (unsigned long)[temp count]);
if([FileCompletedArray count] != [temp count])
{
temp = [FileCompletedArray mutableCopy];
NSLog(#"File Temp 1 array: %#", temp);
[_tableView reloadData];
NSLog(#"File Temp 2 array: %#", temp);
}
[alert dismissWithClickedButtonIndex:0 animated:YES];
//});
}
failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"error: %#", error);
}
];
[httpClient enqueueHTTPRequestOperation:operation];
}
}
And in viewwillappear()
-(void) viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
loop = YES;
temp = [FileCompletedArray mutableCopy];
[self performSelectorInBackground:#selector(updateArray) withObject:nil ];
}
In my function, i used [NSThread sleepForTimeInterval:2.0];, I don't know how to kill it. Do you have suggestions ? Thanks in advance

Answer 1

You shouldn't really use sleepForTimeInterval, you should use performSelector:withObject:afterDelay: (and cancelPerformSelectorsWithTarget:) or dispatch_after.
As it is, you can add a BOOL attribute that is used to decide if the thread should continue after the sleep or whether it should exit (return).

Answer 2

To control any thread you have to use NSOperation Using this you can control any running thread.

Answer 3

Create a BOOL when you click on another tab set it to FALSE. Use this with dispatch after.
#property (nonatomic, assign) BOOL doUpdate;
double delayInSeconds = 2.0;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
if(doUpdate){
//update work.
}
});
You should take look at using NSOperation and then you could call [NSOperation cancelAllOperations] when clicking on a another tab.
Good luck,
Booranger