custom delegate in objective c

Question

i've done a class like this:

testClass <UIAccelerometerDelegate>

and i implement the methods of delegate.

Then in other class where i want this delegate i've done:

testClass *t = [[testClass alloc]init];
UIAccelerometer *a = [UIAccelerometer sharedAccelerometer];
[a setDelegate: t];

and in dealloc i release t.

It works, but is this the right way to write a general delegate?

score 0 · Answer 1 · edited May 23 '17 at 11:47

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In general that is right, but you need to be careful when deciding to retain or assign the delegate to avoid circular references. I have been bit by this before. Here is a good post talking about it and some nuances to be aware of: Why are Objective-C delegates usually given the property assign instead of retain?

edited May 23 '17 at 11:47

Community

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answered Apr 29 '11 at 14:41

ljkyser

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`UIAccelerometer` is apple's class, so the OP doesn't have to worry about any delegate retain/release issues. This answer has nothing to do with the question. – kubi Apr 29 '11 at 14:45
Why the down vote? Did you read the whole question? He is asking if in **GENERAL** that is the right way to use delegates, not just with the `UIAccelerometer` class. If he is releasing it in dealloc, he is retaining it, therefore it is relevant. Read the whole question next time... – ljkyser Apr 29 '11 at 14:51
He was asking how to set delegates for other objects, not how to deal with delegates properties of his own objects. The OP's `testClass` is an iVar of his class, so it must be retained and released. – kubi Apr 29 '11 at 15:09

kubi · Answer 2 · 2011-04-29T15:06:51.617

That is one way to write a delegate. An easier way would be to implement the delegate methods in the class in which you created your testClass instance and set the UIAccelerometer delegate property to self.

Also, just a consistency note, it's proper for class names to start with a capitalized letter, so your class should be called TestClass.

Also, you do need to set the UIAccelerometer delegate property to nil when you deallocate the delegate object.

custom delegate in objective c

2 Answers2