performSelectorOnMainThread method not call - objective-c

Question

I have created a method that is running in new thread.
[NSThread detachNewThreadSelector:#selector(setmostpopularReq:) toTarget:self withObject:mostPopulerstring];
After completed this method i send all data to main thread.
[self performSelectorOnMainThread:#selector(getmostpopularResponse:) withObject:self waitUntilDone:YES];
But some time my main thread method not calling.
i used
dispatch_sync(dispatch_get_main_queue(),^{[self getmostpopularResponse:mostPopularList];});
But this is also have the same problem some time its calling method or some time not calling.
Please help me in this.

Answer 1

I would advise you to create a delegate with which you could notify the main thread after the
completion of the detached thread
Also another solution would be to create an NSOperation and NSOperationQueue instead of a new thread. There you can schedule what you want. For me looks easier, though it depends on you.
Here is a link to help you more with NSOperation
https://developer.apple.com/library/mac/#featuredarticles/ManagingConcurrency/_index.html

Answer 2

I will write this really quickly.
#protocol RespondDelegate
- (void)notifyWithRespond:(NSData *)data;
#end
#interface ContactWebServiceOperation:NSOperation
#property (nonatomic, assign) id delegate;
#end
#implementation ContactWebServiceOperation
#synthesize delegate;
// initialize here.
- (id)initWithDelegate:(id)delegate;
{
if ([self = [super init]) {
self.delegate = delegate;
}
return self;
}
- (void)main
{
if (self.isCancelled) return;
if (nil != delegate) {
// Do your work here...
work();
// When finished notify the delegate with the new data.
[delegate notifyWithRespond:your_data_here];
// Or
[delegate performSelectorOnMainThread:#selector(processImageForDownloadOperation:)
withObject:self waitUntilDone:YES];
}
}
#end
// Now on the view that you want to present the received results
// you have to do one thing.
// Let's say that your view is called View1
#interface View1 : UIViewController<RespondDelegate>
// Here put whatever you like.
#end
#implementation View1
// Put here all your code.
- (void)notifyWithRespond:(NSData *)data
{
// Here you will handle your new data and you will update your view.
}
#end
If I understand correct this should work.
Also, you can change the NSData to whatever you like, as long as you perform the appropriate conversions later.
If it doesn't work take a look on the link from Apple, maybe I have some typo or something.
But in general it looks solid.