perfomSelector on button and sending parameters

问题

I have a method with multiple variables:

-(void) showImg:(UIBarButtonItem *)sender string1:(NSString *) string2:(NSString *);

I want to send NSString values (As this function is used for multiple elements).

This is how I add my action when no parameters are needed:

[myButton addTarget:self action:@selector(showImg) forControlEvents: UIControlEventTouchUpInside];

I tried adding parameters within the @selector like this:

[myButton performSelector @selector(showImg:string1:string2::) withObject:@"-1" withObject:@"-1"];

But this does not work. How may I call my function with multiple parameters directly inside the @selector?

回答1:

You can make your UIButton call a function in between (like a middle man), to control the next functions parameters.

UIButton *myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[myButton addTarget:self action:@selector(buttonTapped:) forControlEvents:UIControlEventTouchUpInside];

-(void) buttonTapped:(id)sender{
    if(<some logical condition>){
        [self showImg:sender string1:@"-1" string2:@"-1"];
    }else {
        [self showImg:sender string1:@"otherVal1" string2:@"otherVal2"];
    }
}

-(void) showImg:(id)sender string1:(NSString *)string1 string2:(NSString*)string2 {
    //Other logic
}

回答2:

The following line is wrong :

[myButton performSelector @selector(showImg:string1:string2::) withObject:@"-1" withObject:@"-1"];

You can't pass parameters like this to the selector, that's why you have an error. I don't think you can pass multiple parameters to a selector. Maybe you can try to set a tag to your button with your const value (works with integers)

For example :

//Init your button......
[myButton setTag:1];
[myButton addTarget:self action:@selector(showImg:) forControlEvents: UIControlEventTouchUpInside];

- (void)showImg:(id)sender {
  UIButton *btn = (UIButton *)sender;
  int value = btn.tag;
}

Just a suggestion.. :)

来源：https://stackoverflow.com/questions/12763733/perfomselector-on-button-and-sending-parameters

标签

iphone

objective-c

selector