threading for network calls in iOS 5

Question

I have been looking over the internet, but could not find the perfect tutorial for threading in iOS, currently i am working on iOS 5 , tutorial found on web were old, my app needs to fetch data from webservices, so I want to call network operation in a thread, I have a tabbar, in each tab it loads different type of data from web, as it start fetching data , I dont want my app to stuck on that tab, i want that user can navigate to other tab meanwhile its fetching data for that tab. how can it be possible

EDIT: I want to have a flow :

 //in a thread
 fetchDataFromWeb(){//during this call activity indicator
 //fetch and make an array of ojbects     
 }

when data is loaded trigger the populate funciton

laoddata(){//remove activity indicator
//load tableview and other views
}

how will i know my thread finished its process

take a look at this : https://github.com/AFNetworking/AFNetworking — Y2theZ, Sep 21 '12 at 08:17

Alex Terente · Accepted Answer · 2012-09-21T10:25:53.740

1

Take a look to NSOperation, NSThread or Grand Central Dispatch

Edit: NSThread example

//on main thread on some action
 NSDictionary *myParameterDitionary = [..];
 [NSThread detachNewThreadSelector:@selector(aBackThreadMethod:) toTarget:self withObject:myParameterDitionary];

//this is on back thread called
- (void)aBackThreadMethod:(NSDictionary *)variablesDictionary{
    @autoreleasepool {
        //presess data
        NSDictionary *responseDictionary = [..];
        [self performSelectorOnMainThread:@selector(didABackThreadMethod:) withObject:responseDictionary waitUntilDone:YES];
    }
}

//call back on main thread
- (void)didFinishABackThreadMethod:(NSDictionary *)responseDictionary{
   //do stuff ex update views
}

The @autoreleasepool is for ARC. If you use manual memory management you have to do:

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
[pool release];

edited Sep 21 '12 at 10:25

answered Sep 21 '12 at 05:48

Alex Terente

12,006
5
51
71

there is no understandable example, – Raheel Sadiq Sep 21 '12 at 07:25
1

you just want copy paste code? Did you tried to use one of this classes and you failed? Edit your question pasting some code and where the problem is, or just post new question with what have you tried. – Alex Terente Sep 21 '12 at 07:35
i tried using NSThreads before but failed now reading the document again, it creates a thread and run efficiently but the main UIThread is still stuck – Raheel Sadiq Sep 21 '12 at 07:43
I have been working in both environments android and ios, in android it is well managed with AsyncTask, here I am not able to free Main UIThread – Raheel Sadiq Sep 21 '12 at 07:44
when u create a thread with detachNewThreadSelector, it doesn't free the main UIThread – Raheel Sadiq Sep 21 '12 at 07:48
yes it does. if it is blocked it means that something else is blocking it. I will edit and add a example for NSThread – Alex Terente Sep 21 '12 at 08:00
your example solved half of my issue, i made an edit, please check – Raheel Sadiq Sep 21 '12 at 10:11
ok i get it now here i can call my loadview functions - (void)didABackThreadMethod:(NSDictionary *)responseDictionary{ – Raheel Sadiq Sep 21 '12 at 10:13

threading for network calls in iOS 5

1 Answers1