Passing parameters to addTarget:action:forControlEvents

Question

action:@selector(switchToNewsDetails:)

You do not pass parameters to switchToNewsDetails: method here. You just create a selector to make button able to call it when certain action occurs (touch up in your case). Controls can use 3 types of selectors to respond to actions, all of them have predefined meaning of their parameters:

1. with no parameters

   action:@selector(switchToNewsDetails)
   

2. with 1 parameter indicating the control that sends the message

   action:@selector(switchToNewsDetails:)
   

3. With 2 parameters indicating the control that sends the message and the event that triggered the message:

   action:@selector(switchToNewsDetails:event:)
   

It is not clear what exactly you try to do, but considering you want to assign a specific details index to each button you can do the following:

1. set a tag property to each button equal to required index

2. in switchToNewsDetails: method you can obtain that index and open appropriate deatails:

   - (void)switchToNewsDetails:(UIButton*)sender{
       [self openDetails:sender.tag];
       // Or place opening logic right here
   }
   

To pass custom params along with the button click you just need to SUBCLASS UIButton.

(ASR is on, so there's no releases in the code.)

This is myButton.h

#import <UIKit/UIKit.h>

@interface myButton : UIButton {
    id userData;
}

@property (nonatomic, readwrite, retain) id userData;

@end

This is myButton.m

#import "myButton.h"
@implementation myButton
@synthesize userData;
@end

Usage:

myButton *bt = [myButton buttonWithType:UIButtonTypeCustom];
[bt setFrame:CGRectMake(0,0, 100, 100)];
[bt setExclusiveTouch:NO];
[bt setUserData:**(insert user data here)**];

[bt addTarget:self action:@selector(touchUpHandler:) forControlEvents:UIControlEventTouchUpInside];

[view addSubview:bt];

Recieving function:

- (void) touchUpHandler:(myButton *)sender {
    id userData = sender.userData;
}

If you need me to be more specific on any part of the above code — feel free to ask about it in comments.

Target-Action allows three different forms of action selector:

- (void)action
- (void)action:(id)sender
- (void)action:(id)sender forEvent:(UIEvent *)event

Need more than just an (int) via .tag? Use KVC!

You can pass any data you want through the button object itself (by accessing CALayers keyValue dict).

---

Set your target like this (with the ":")

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

---

Add your data(s) to the button itself (well the .layer of the button that is) like this:

NSString *dataIWantToPass = @"this is my data";//can be anything, doesn't have to be NSString
[myButton.layer setValue:dataIWantToPass forKey:@"anyKey"];//you can set as many of these as you'd like too!

---

Then when the button is tapped you can check it like this:

-(void)buttonTap:(UIButton*)sender{

    NSString *dataThatWasPassed = (NSString *)[sender.layer valueForKey:@"anyKey"];
    NSLog(@"My passed-thru data was: %@", dataThatWasPassed);

}

I made a solution based in part by the information above. I just set the titlelabel.text to the string I want to pass, and set the titlelabel.hidden = YES

Like this :

UIButton *imageclick = [[UIButton buttonWithType:UIButtonTypeCustom] retain];
imageclick.frame = photoframe;
imageclick.titleLabel.text = [NSString stringWithFormat:@"%@.%@", ti.mediaImage, ti.mediaExtension];
imageclick.titleLabel.hidden = YES;

This way, there is no need for a inheritance or category and there is no memory leak