peformSelector with two arguments

Question

I've to run this method on background or in new thread. How to pass two arguments in performSelector?

[self addMessageFromRemoteNotification:userInfo updateUI:NO];

-(void)addMessageFromRemoteNotification:(NSDictionary *)userInfo updateUI:(BOOL)updateUI
{
}

This will help you. http://stackoverflow.com/questions/2716143/sel-performselector-and-arguments/9108934#9108934 — yunas, May 28 '13 at 14:07
see my answer to this question: http://stackoverflow.com/questions/16731105/how-can-i-pass-multiple-objects-to-a-delayed-method/16731378#16731378 — pmk, May 28 '13 at 14:10

jjxtra · Answer 1 · 2013-05-28T18:32:57.847

1

If you must use performSelector and you want N parameters, simply wrap them in an array or dictionary and make the signature of the called method have a single parameter of NSArray or NSDictionary. Any primitive types (like int, float, etc.) will need to be wrapped in NSNumber.

Example With NSArray:

- (void) addMessageFromRemoteNotification:(NSArray*)parameters
{
}

...

[self performSelector:@selector(addMessageFromRemoteNotification:)
withObject:@[ obj1, obj2, obj3, @(4.0f)]];

Example With NSDictionary:

- (void) addMessageFromRemoteNotification:(NSDictionary*)parameters
{
}

...

[self performSelector:@selector(addMessageFromRemoteNotification:)
withObject:@{ @"prop1": @"prop1value", @"prop2": @(4.0f) }];

Good luck!

edited May 28 '13 at 18:32

answered May 28 '13 at 16:28

jjxtra

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I'd go for a NSDictionary instead of a NSArray, but this answers the question :) – Bruno Koga May 28 '13 at 17:40
Updated to show an NSDictionary example – jjxtra May 28 '13 at 18:33

score 0 · Answer 2 · answered May 28 '13 at 14:08

0

there is method

[self performSelector:@selector(addMessageFromRemoteNotification:) withObject:param1 withObject:param2];

you can use this.

answered May 28 '13 at 14:08

Harshal Chaudhari

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Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[AppDelegate addMessageFromRemoteNotification:]: unrecognized selector sent to instance 0x21c7b0' – dineshsurya May 28 '13 at 14:13
I got this exception... – dineshsurya May 28 '13 at 14:14
I am pretty sure `-performSelector:withObject:withObject:` is just made up. – Grady Player May 28 '13 at 15:00
@GradyPlayer No, it is a real method, but it does not send the message to a background thread. Check the header. – bbum May 28 '13 at 15:34
@dineshsurya Read the error message. Your `AppDelegate` does not implement that method. Has nothing to do with the `performSelector:...` call; not that this particular call would solve your problem anyway. – bbum May 28 '13 at 15:35
@bbum oh yeah I now see it is in ios... sorry – Grady Player May 28 '13 at 16:00
The selector name is incomplete. If you give it two parameters, you will need two colons in your selector name. – Scott Berrevoets May 29 '13 at 02:36

SomaMan · Answer 3 · 2013-05-29T02:16:22.897

0

Just create a model class for the data you want to send, eg -

@interface Car : NSObject

@property (nonatomic, strong) NSString *manufacturer;
@property (nonatomic, strong) NSString *colour;
@property (nonatomic, strong) NSDate *year;

@end

Then pass an instance of it in your performSelector: method.

It's often better than passing multiple parameters anyway, in case you decide to change the data model (eg, add more properties) - though it will depend on the circumstances of course.

edited May 29 '13 at 02:16

answered May 28 '13 at 14:51

SomaMan

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This isn't wrong, but it is a little heavy-handed; just use a dictionary... that is what the framework does everywhere: `NSDictionary * userInfo` – Grady Player May 28 '13 at 14:59
Also probably a matter of programming style, or if the parameters suit it (eg, if you're often using multiple parameters in your code, would a dedicated model make things clearer) – SomaMan May 29 '13 at 02:19

peformSelector with two arguments

3 Answers3