Swift: A function with a Selector argument returns an unmanaged?
What is the use of -
func perform(_ aSelector: Selector!) -> unmanaged<AnyObject>!
in iOS?
- To call a method of a class?
- To add a selector method?
- To add a class delegate?
- To define a class? (I doubt it's this)
I was originally thinking that it it was to add a selector method, but after looking at it some more I think it may be "to call a method of a class." Selectors are used for target/action paradigms where I kick something off and when the event fires or finishes then it wants to fire off some kind of action method.
In this example do I pass it a parameter of a selector function then at the end of this "perform" function, I am returning an unmanaged object of any type? Does that even make sense?
Thanks!
ios swift
asked Nov 14 '18 at 23:35
TSupermanTSuperman
485
add a comment |
What is the use of -
func perform(_ aSelector: Selector!) -> unmanaged<AnyObject>!
in iOS?
- To call a method of a class?
- To add a selector method?
- To add a class delegate?
- To define a class? (I doubt it's this)
I was originally thinking that it it was to add a selector method, but after looking at it some more I think it may be "to call a method of a class." Selectors are used for target/action paradigms where I kick something off and when the event fires or finishes then it wants to fire off some kind of action method.
In this example do I pass it a parameter of a selector function then at the end of this "perform" function, I am returning an unmanaged object of any type? Does that even make sense?
Thanks!
ios swift
asked Nov 14 '18 at 23:35
TSupermanTSuperman
485
Are you referring to the method fromNSObjectProtocolwhich is from the Objective-C runtime?
– rmaddy
Nov 14 '18 at 23:41
@rmaddy --> I don't know. This was asked on a quiz that I was taking and I didn't have any other information for this question.
– TSuperman
Nov 14 '18 at 23:49
@rmaddy -> If the method was referring to the NSObjectProtocol, would it have a different meaning or do something that I wouldn't normally expect?
– TSuperman
Nov 15 '18 at 0:01
1
Basically it's something you would very rarely, if ever, use in Swift. It should rarely be used directly any more in Objective-C.
– rmaddy
Nov 15 '18 at 0:03
1
Indeed this used to be forbidden in Swift, and even now should be avoided, as Swift provides better ways. See stackoverflow.com/questions/24158427/… for example
– matt
Nov 15 '18 at 0:55
add a comment |
What is the use of -
func perform(_ aSelector: Selector!) -> unmanaged<AnyObject>!
in iOS?
- To call a method of a class?
- To add a selector method?
- To add a class delegate?
- To define a class? (I doubt it's this)
I was originally thinking that it it was to add a selector method, but after looking at it some more I think it may be "to call a method of a class." Selectors are used for target/action paradigms where I kick something off and when the event fires or finishes then it wants to fire off some kind of action method.
In this example do I pass it a parameter of a selector function then at the end of this "perform" function, I am returning an unmanaged object of any type? Does that even make sense?
Thanks!
ios swift
asked Nov 14 '18 at 23:35
TSupermanTSuperman
485
What is the use of -
func perform(_ aSelector: Selector!) -> unmanaged<AnyObject>!
in iOS?
- To call a method of a class?
- To add a selector method?
- To add a class delegate?
- To define a class? (I doubt it's this)
I was originally thinking that it it was to add a selector method, but after looking at it some more I think it may be "to call a method of a class." Selectors are used for target/action paradigms where I kick something off and when the event fires or finishes then it wants to fire off some kind of action method.
In this example do I pass it a parameter of a selector function then at the end of this "perform" function, I am returning an unmanaged object of any type? Does that even make sense?
Thanks!
ios swift
ios swift
asked Nov 14 '18 at 23:35
TSupermanTSuperman
485
asked Nov 14 '18 at 23:35
TSupermanTSuperman
485
asked Nov 14 '18 at 23:35
TSupermanTSuperman
485
asked Nov 14 '18 at 23:35
TSupermanTSuperman
485
asked Nov 14 '18 at 23:35
TSupermanTSuperman
485
485
Are you referring to the method fromNSObjectProtocolwhich is from the Objective-C runtime?
– rmaddy
Nov 14 '18 at 23:41
@rmaddy --> I don't know. This was asked on a quiz that I was taking and I didn't have any other information for this question.
– TSuperman
Nov 14 '18 at 23:49
@rmaddy -> If the method was referring to the NSObjectProtocol, would it have a different meaning or do something that I wouldn't normally expect?
– TSuperman
Nov 15 '18 at 0:01
1
Basically it's something you would very rarely, if ever, use in Swift. It should rarely be used directly any more in Objective-C.
– rmaddy
Nov 15 '18 at 0:03
1
Indeed this used to be forbidden in Swift, and even now should be avoided, as Swift provides better ways. See stackoverflow.com/questions/24158427/… for example
– matt
Nov 15 '18 at 0:55
add a comment |
Are you referring to the method fromNSObjectProtocolwhich is from the Objective-C runtime?
– rmaddy
Nov 14 '18 at 23:41
@rmaddy --> I don't know. This was asked on a quiz that I was taking and I didn't have any other information for this question.
– TSuperman
Nov 14 '18 at 23:49
@rmaddy -> If the method was referring to the NSObjectProtocol, would it have a different meaning or do something that I wouldn't normally expect?
– TSuperman
Nov 15 '18 at 0:01
1
Basically it's something you would very rarely, if ever, use in Swift. It should rarely be used directly any more in Objective-C.
– rmaddy
Nov 15 '18 at 0:03
1
Indeed this used to be forbidden in Swift, and even now should be avoided, as Swift provides better ways. See stackoverflow.com/questions/24158427/… for example
– matt
Nov 15 '18 at 0:55
Are you referring to the method from
NSObjectProtocol which is from the Objective-C runtime?– rmaddy
Nov 14 '18 at 23:41
Are you referring to the method from
NSObjectProtocol which is from the Objective-C runtime?– rmaddy
Nov 14 '18 at 23:41
@rmaddy --> I don't know. This was asked on a quiz that I was taking and I didn't have any other information for this question.
– TSuperman
Nov 14 '18 at 23:49
@rmaddy --> I don't know. This was asked on a quiz that I was taking and I didn't have any other information for this question.
– TSuperman
Nov 14 '18 at 23:49
@rmaddy -> If the method was referring to the NSObjectProtocol, would it have a different meaning or do something that I wouldn't normally expect?
– TSuperman
Nov 15 '18 at 0:01
@rmaddy -> If the method was referring to the NSObjectProtocol, would it have a different meaning or do something that I wouldn't normally expect?
– TSuperman
Nov 15 '18 at 0:01
1
1
Basically it's something you would very rarely, if ever, use in Swift. It should rarely be used directly any more in Objective-C.
– rmaddy
Nov 15 '18 at 0:03
Basically it's something you would very rarely, if ever, use in Swift. It should rarely be used directly any more in Objective-C.
– rmaddy
Nov 15 '18 at 0:03
1
1
Indeed this used to be forbidden in Swift, and even now should be avoided, as Swift provides better ways. See stackoverflow.com/questions/24158427/… for example
– matt
Nov 15 '18 at 0:55
Indeed this used to be forbidden in Swift, and even now should be avoided, as Swift provides better ways. See stackoverflow.com/questions/24158427/… for example
– matt
Nov 15 '18 at 0:55
add a comment |
1 Answer
1
active
oldest
votes
In Swift this is basically useless. It's bridged from Objective-C, where it used to be very useful (before ARC), but now it's a bit tricky.
The point of it is to send a message by name and get a result. Generally speaking that translates to calling a method of that name.
answered Nov 14 '18 at 23:41
Rob NapierRob Napier
203k28299425
So basically this is "calling a method" and returning some data type? Not a nice way of doing it, but a long, obnoxious way of doing it?
– TSuperman
Nov 14 '18 at 23:44
1
It's only obnoxious in Swift. In ObjC, it's pretty elegant, and is the core tool used for all the target/action features like UIButton, NSTimer, and the like.
– Rob Napier
Nov 15 '18 at 0:02
Thanks! I have been writing more Swift code than Objective-C.
– TSuperman
Nov 15 '18 at 0:42
Is this method just short-hand for the ObjC runtime APIs likeclass_getMethodImplementation(AnyClass?, Selector)?
– Alexander
Nov 15 '18 at 1:37
1
@Alexander It's a wrapper aroundobjc_msgSend. You can see the source code for it here: opensource.apple.com/source/objc4/objc4-723/runtime/…
– Rob Napier
Nov 15 '18 at 13:46
add a comment |
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1 Answer
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oldest
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1 Answer
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active
oldest
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oldest
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oldest
votes
In Swift this is basically useless. It's bridged from Objective-C, where it used to be very useful (before ARC), but now it's a bit tricky.
The point of it is to send a message by name and get a result. Generally speaking that translates to calling a method of that name.
answered Nov 14 '18 at 23:41
Rob NapierRob Napier
203k28299425
So basically this is "calling a method" and returning some data type? Not a nice way of doing it, but a long, obnoxious way of doing it?
– TSuperman
Nov 14 '18 at 23:44
1
It's only obnoxious in Swift. In ObjC, it's pretty elegant, and is the core tool used for all the target/action features like UIButton, NSTimer, and the like.
– Rob Napier
Nov 15 '18 at 0:02
Thanks! I have been writing more Swift code than Objective-C.
– TSuperman
Nov 15 '18 at 0:42
Is this method just short-hand for the ObjC runtime APIs likeclass_getMethodImplementation(AnyClass?, Selector)?
– Alexander
Nov 15 '18 at 1:37
1
@Alexander It's a wrapper aroundobjc_msgSend. You can see the source code for it here: opensource.apple.com/source/objc4/objc4-723/runtime/…
– Rob Napier
Nov 15 '18 at 13:46
add a comment |
In Swift this is basically useless. It's bridged from Objective-C, where it used to be very useful (before ARC), but now it's a bit tricky.
The point of it is to send a message by name and get a result. Generally speaking that translates to calling a method of that name.
answered Nov 14 '18 at 23:41
Rob NapierRob Napier
203k28299425
So basically this is "calling a method" and returning some data type? Not a nice way of doing it, but a long, obnoxious way of doing it?
– TSuperman
Nov 14 '18 at 23:44
1
It's only obnoxious in Swift. In ObjC, it's pretty elegant, and is the core tool used for all the target/action features like UIButton, NSTimer, and the like.
– Rob Napier
Nov 15 '18 at 0:02
Thanks! I have been writing more Swift code than Objective-C.
– TSuperman
Nov 15 '18 at 0:42
Is this method just short-hand for the ObjC runtime APIs likeclass_getMethodImplementation(AnyClass?, Selector)?
– Alexander
Nov 15 '18 at 1:37
1
@Alexander It's a wrapper aroundobjc_msgSend. You can see the source code for it here: opensource.apple.com/source/objc4/objc4-723/runtime/…
– Rob Napier
Nov 15 '18 at 13:46
add a comment |
In Swift this is basically useless. It's bridged from Objective-C, where it used to be very useful (before ARC), but now it's a bit tricky.
The point of it is to send a message by name and get a result. Generally speaking that translates to calling a method of that name.
answered Nov 14 '18 at 23:41
Rob NapierRob Napier
203k28299425
In Swift this is basically useless. It's bridged from Objective-C, where it used to be very useful (before ARC), but now it's a bit tricky.
The point of it is to send a message by name and get a result. Generally speaking that translates to calling a method of that name.
answered Nov 14 '18 at 23:41
Rob NapierRob Napier
203k28299425
answered Nov 14 '18 at 23:41
Rob NapierRob Napier
203k28299425
answered Nov 14 '18 at 23:41
Rob NapierRob Napier
203k28299425
answered Nov 14 '18 at 23:41
Rob NapierRob Napier
203k28299425
203k28299425
So basically this is "calling a method" and returning some data type? Not a nice way of doing it, but a long, obnoxious way of doing it?
– TSuperman
Nov 14 '18 at 23:44
1
It's only obnoxious in Swift. In ObjC, it's pretty elegant, and is the core tool used for all the target/action features like UIButton, NSTimer, and the like.
– Rob Napier
Nov 15 '18 at 0:02
Thanks! I have been writing more Swift code than Objective-C.
– TSuperman
Nov 15 '18 at 0:42
Is this method just short-hand for the ObjC runtime APIs likeclass_getMethodImplementation(AnyClass?, Selector)?
– Alexander
Nov 15 '18 at 1:37
1
@Alexander It's a wrapper aroundobjc_msgSend. You can see the source code for it here: opensource.apple.com/source/objc4/objc4-723/runtime/…
– Rob Napier
Nov 15 '18 at 13:46
add a comment |
So basically this is "calling a method" and returning some data type? Not a nice way of doing it, but a long, obnoxious way of doing it?
– TSuperman
Nov 14 '18 at 23:44
1
It's only obnoxious in Swift. In ObjC, it's pretty elegant, and is the core tool used for all the target/action features like UIButton, NSTimer, and the like.
– Rob Napier
Nov 15 '18 at 0:02
Thanks! I have been writing more Swift code than Objective-C.
– TSuperman
Nov 15 '18 at 0:42
Is this method just short-hand for the ObjC runtime APIs likeclass_getMethodImplementation(AnyClass?, Selector)?
– Alexander
Nov 15 '18 at 1:37
1
@Alexander It's a wrapper aroundobjc_msgSend. You can see the source code for it here: opensource.apple.com/source/objc4/objc4-723/runtime/…
– Rob Napier
Nov 15 '18 at 13:46
So basically this is "calling a method" and returning some data type? Not a nice way of doing it, but a long, obnoxious way of doing it?
– TSuperman
Nov 14 '18 at 23:44
So basically this is "calling a method" and returning some data type? Not a nice way of doing it, but a long, obnoxious way of doing it?
– TSuperman
Nov 14 '18 at 23:44
1
1
It's only obnoxious in Swift. In ObjC, it's pretty elegant, and is the core tool used for all the target/action features like UIButton, NSTimer, and the like.
– Rob Napier
Nov 15 '18 at 0:02
It's only obnoxious in Swift. In ObjC, it's pretty elegant, and is the core tool used for all the target/action features like UIButton, NSTimer, and the like.
– Rob Napier
Nov 15 '18 at 0:02
Thanks! I have been writing more Swift code than Objective-C.
– TSuperman
Nov 15 '18 at 0:42
Thanks! I have been writing more Swift code than Objective-C.
– TSuperman
Nov 15 '18 at 0:42
Is this method just short-hand for the ObjC runtime APIs like
class_getMethodImplementation(AnyClass?, Selector)?– Alexander
Nov 15 '18 at 1:37
Is this method just short-hand for the ObjC runtime APIs like
class_getMethodImplementation(AnyClass?, Selector)?– Alexander
Nov 15 '18 at 1:37
1
1
@Alexander It's a wrapper around
objc_msgSend. You can see the source code for it here: opensource.apple.com/source/objc4/objc4-723/runtime/…– Rob Napier
Nov 15 '18 at 13:46
@Alexander It's a wrapper around
objc_msgSend. You can see the source code for it here: opensource.apple.com/source/objc4/objc4-723/runtime/…– Rob Napier
Nov 15 '18 at 13:46
add a comment |
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Are you referring to the method from
NSObjectProtocolwhich is from the Objective-C runtime?– rmaddy
Nov 14 '18 at 23:41
@rmaddy --> I don't know. This was asked on a quiz that I was taking and I didn't have any other information for this question.
– TSuperman
Nov 14 '18 at 23:49
@rmaddy -> If the method was referring to the NSObjectProtocol, would it have a different meaning or do something that I wouldn't normally expect?
– TSuperman
Nov 15 '18 at 0:01
1
Basically it's something you would very rarely, if ever, use in Swift. It should rarely be used directly any more in Objective-C.
– rmaddy
Nov 15 '18 at 0:03
1
Indeed this used to be forbidden in Swift, and even now should be avoided, as Swift provides better ways. See stackoverflow.com/questions/24158427/… for example
– matt
Nov 15 '18 at 0:55