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August 29, 2015 13:56
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Strong/Weak/Strong Again
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| @property (strong, nonatomic) id observer; | |
| // ... | |
| - (void)startListening | |
| { | |
| __weak MyClass *wself = self; | |
| self.observer = | |
| [[NSNotificationCenter defaultCenter] addObserverForName:@"foo" object:nil queue:nil usingBlock:^(NSNotification *note){ | |
| MyClass *sself = wself; | |
| if (sself != nil) | |
| { | |
| // Look ma, no retain cycles (provided all I reference is sself) | |
| } | |
| }]; | |
| } |
Weak references are inherently volatile; wself could go away between any two lines of code. Maybe that's not an issue in your case, in which case (since it's an ARC weak ref) you'll just send lots of messages to nil. Or maybe it is an issue, in which case you'd better re-form the sself strong reference.
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Why the
sselfdeclaration in the block? Can't you just refer towself, or is this just for demonstration purposes?