I want to call instance methods inside a block. Here is the method that I am working with,
[self.someVariable addBoundaryTimeObserverForTimes:timeArray queue:NULL usingBlock:^{
[self myInstanceMethod];
}];
But I am not able to reference self from inside this block. What should I do?
EDIT: I am sorry that I posted this question in a hurry. Actually I was getting a warning (Capturing 'self' strongly in this block is likely to lead to a retain cycle) with this approach.
Using self directly inside a block may cause a retain cycle, to avoid a retain cycle you should create a weak reference to self and then use that reference inside the block to call your instance methods. Use the below code to call instance methods inside a block
__weak YourViewController * weakSelf = self;
[self.someVariable addBoundaryTimeObserverForTimes:timeArray queue:NULL usingBlock:^{
[weakSelf myInstanceMethod];
}];
Try this code :
__block YourViewController *blockSafeSelf = self;
[self.someVariable addBoundaryTimeObserverForTimes:timeArray queue:NULL usingBlock:^{
[blockSafeSelf myInstanceMethod];
}];
_block will retain self, so you can also use a _weak reference :
YourViewController * __weak weakSelf = self;
[self.someVariable addBoundaryTimeObserverForTimes:timeArray queue:NULL usingBlock:^{
[weakSelf myInstanceMethod];
}];
if you want to call instance method inside a block . you could try the below code and it's suggested by apple and here is a link for https://developer.apple.com/library/mac/referencelibrary/GettingStarted/RoadMapOSX/books/AcquireBasicProgrammingSkills/AcquireBasicSkills/AcquireBasicSkills.html
__block typeof(self) tmpSelf = self;
[self.someVariable addBoundaryTimeObserverForTimes:timeArray queue:NULL usingBlock:^{
[tmpSelf myInstanceMethod];
}];
For example
//References to self in blocks
__block typeof(self) tmpSelf = self;
[self methodThatTakesABlock:^ {
[tmpSelf doSomething];
}];Yes you can do this.
__block YourViewController *blockInstance = self;
[self.someVariable addBoundaryTimeObserverForTimes:timeArray queue:NULL usingBlock:^{
[blockInstance myInstanceMethod];
}];
Note : However, that the block will retain self. If you end up storing this block in an ivar, you could easily create a retain cycle, which means neither would ever get deallocated.
To avoid this problem, it’s best practice to capture a weak reference to self, like this:
__weak YourViewController *weakSelf = self;
[self.someVariable addBoundaryTimeObserverForTimes:timeArray queue:NULL usingBlock:^{
[weakSelf myInstanceMethod];
}];
