Objective C calling method dynamically with a string
Solution 1
You can try something like
SEL s = NSSelectorFromString(selectorName);
[anObject performSelector:s];
Solution 2
You can use the objc_msgSend function. It takes two parameters, the receiver and the selector to send to it:
objc_msgSend(self, someSelector);
You'll need to turn your string into the appropriate selector using NSSelectorFromString
:
NSString *message = [self getSomeSelectorName];
objc_msgSend(self, message);
The method also takes a variable number of arguments, so you can send messages with any number of arguments.
NSString *message = [self getSomeSelectorNameWithManyArguments];
objc_msgSend(self, message, arg1, arg2, arg3, arg4);
IPadHackAndSlash
Updated on July 05, 2022Comments
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IPadHackAndSlash almost 2 years
Im just wondering whether there is a way to call a method where i build the name of the method on the fly with a string.
e.g. I have a method called loaddata
-(void)loadData;
to call this i would normally call it like
[self loadData];
But i want to be able to call it dynamically with a string e.g.
NSString *methodName = [[NSString alloc] initWithString:@"loadData"]; [self methodName];
This is a stupid example but i hope you get my point. I am using it for databinding classes that I am setting up for my IPad application. Hard to explain but to get it to fire I need to work out how to call a method with a string.
Any ideas?
Thanks
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IPadHackAndSlash over 13 yearsIn this situation the method returns a value which is an NSString in one case. I get an error saying Lvalue required as left operand of assignment. This is my code: SEL s = NSSelectorFromString(@"getIDString"); [self text] = [boundEntity performSelector:s];
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Ishu over 13 yearswhat is [self text],where you assign the value return getIDString.
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shreyasva over 13 years
[boundEntity performSelector:s]
returns a value of type that does not match the type of[self text]
. I think you need to set @property for text and call[self setText:[[boundEntity performSelector:s]]]
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malhal over 10 yearsperformSelector may cause a leak because selector is unknown!
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SexyBeast over 9 years