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POHow do I know if I am executing something on the UI thread?
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  1. POHow do I know if I am executing something on the UI thread?
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    copied!<p>I wrote a test to experiment with RestKit using blocks. I thought that the <code>RKRequest.onDidLoadResponse</code> would need to contain a <code>dispatch_async()</code> call to get the response on the main UI thread, though to my surprise this turned out to cause a runtime exception, so I took it out and I could update the interface quite fine.</p> <p>My code in question is as follows:</p> <pre><code>- (IBAction)loadSeasons:(UIButton *)sender { [[RKClient sharedClient] get:@"/api/v1/seasons" usingBlock:^(RKRequest* req) { req.onDidLoadResponse = ^(RKResponse* res) { NSLog(@"Request Performed: %@", res.bodyAsString); self.textResponse.text = res.bodyAsString; //dispatch_async(dispatch_get_main_queue(), ^{ // NSLog(@"In main queue: %@", res.bodyAsString); //}); }; }]; } </code></pre> <p>If I uncomment the <code>dispatch_async</code> block I get the exception. So how do I know when I need to use this and when I should not need to? Should I test for something that tells me if the code being executed is on the main thread or not?</p> <p>I am new to Objective-C and it's early days for me so I do apologise for what may be a newbie question.</p> <p><strong>UPDATE</strong>: When uncommenting the code above the following happens:</p> <ol> <li>The console outputs the text <code>(lldb)</code> in blue, no other information is provided.</li> <li>A break on <code>libobjc.A.dylib</code>objc_msgSend:<code>is shown in the editor on</code>0x1c2009b: movl 8(%edx), %edi<code>with the message in green:</code>Thread 1: EXC_BAD_ACCESS (code=1, address=0x40000008)`.</li> </ol>
 

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