How to pass 3 parameters to @selector

Question

I created an action in

-(void) ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event

which just like this:

self.moveAction = [CCSequence actions:                          
                   [CCMoveTo actionWithDuration:moveDuration position:touchLocation],
                   [CCCallFunc actionWithTarget:self selector:@selector(guyMoveEnded)],
                   nil
                  ];

but now, I want to auto-invoke a following method by @selector:

-(void)guyMoveEnded:(BOOL)flag AndWhere:(CGPoint)where Andtime:(float)time{
    //do something...
}

How can I do it? Please help me, I'm confused about the selector.

Thanx!

EsbenB · Accepted Answer · 2012-07-27T08:06:47.987

10

You could add your parameters to a NSArray and then give it as the argument to your selector:

NSArray *params = [NSArray arrayWithObjects:@"a str", [NSNumber numberWithInt:42],myObj];
[self performSelector:@selector(myMethod:)withObject:params];

And then unpack the arguments in your method:

-(void)myMethode:(NSArray*)params
{
    NSString *strArg = [params objectAtIndex:0];
    NSNumber * numVal = [params objectAtIndex:1];
    NSObject *objArg = [params objectAtIndex:2];
    int intArg = [numVal intValue];
    .
    .
    .   
}

edited Jul 27 '12 at 08:06

answered Jul 27 '12 at 07:24

EsbenB

3,356
25
44

1

This is the easiest way, the harder way involves NSInvocation. +1 – borrrden Jul 27 '12 at 07:32
I think your code uses `numVal` and then `intVal`... They are supposed to be the same var, right? – Nicolas Miari Jul 27 '12 at 08:05

score 3 · Answer 2 · edited May 23 '17 at 12:32

3

Apple suggests using NSInvocation when you need to pass more than 2 arguments. Here's a very good example: NSInvocation for Dummies?

A short synopsis from that answer with no explanations:

// Prepare the object
NSMethodSignature * mySignature = [NSMutableArray 
    instanceMethodSignatureForSelector:@selector(addObject:)];
NSInvocation * myInvocation = [NSInvocation
    invocationWithMethodSignature:mySignature];

// Set selector and object
[myInvocation setTarget:myArray];
[myInvocation setSelector:@selector(addObject:)];

// Set arguments
[myInvocation setArgument:&myString atIndex:2];

// Invoke it
[myInvocation invoke];

It is a lot more code than just calling a selector with performSelector:, but allows you to call methods with any number of arguments. This is especially useful if you can't change the signature to decrease argument count, as Cipramill suggests.

edited May 23 '17 at 12:32

Community

1
1

answered Jul 27 '12 at 07:41

coverback

4,413
1
19
31

@coverback I think you mean "with more than TWO parameters" OR "with 3 parameters OR MORE" – Nicolas Miari Jul 27 '12 at 08:07
...unles there's a `-performSelector:withObject:withObject:withObject:` that I'm not aware of :) – Nicolas Miari Jul 27 '12 at 08:08
1

Yeath,apple advice if you post more than 2 parameters you should better use NSInvocation – cloosen Jul 27 '12 at 09:39

score 1 · Answer 3 · answered Jul 27 '12 at 07:50

1

Prepare a NSDictionary object with your Parameters & pass that Dictionary to your selector & you can get the values inside your method from Dictionary. following is for reference:

 "NSDictionary *dictionary = nil;
  BOOL flag = YES;
  CGFloat time;
  CGPoint pt;
 [dictionary setValue:flag forKey:FIRSTPARAM];
  [dictionary setValue:time forKey:SECONDPARAM];
  [dictionary setObject:point forKey:THIRDPARAM];
[self performSelector:@selector(methodName:) withObject:dictionary];

"

Either You can create your custom class for that Pass the object of that class.

answered Jul 27 '12 at 07:50

Piyush

244
1
2
8

your answer is the most detailed ,thanks so much,i'll try it. – smileVann Jul 27 '12 at 07:59
1

In my opinion, using a dictionary is better than an array because each object can be 'named' meaningfully (by its key). Of course, you could use an `enum` with meaningful names for the indices of the array... – Nicolas Miari Jul 27 '12 at 08:06

score -1 · Answer 4 · edited Mar 06 '14 at 07:33

[favProductCell.btnAddtoCart addTarget:self action:@selector(arrayForAddToCart:) forControlEvents:UIControlEventTouchUpInside];

[favProductCell.btnAddtoCart setTag:indexPath.row];

-(void)arrayForAddToCart:(id)sender
{
    if (![self.addToCartProductIdArray containsObject:self.favoriteProductArray[[sender tag]]])
        [self.addToCartProductIdArray addObject:self.favoriteProductArray[[sender tag]]];
}

How to pass 3 parameters to @selector

4 Answers4