Passing parameters to addTarget:action:forControlEvents

I am using addTarget:action:forControlEvents like this:

<pre><code>[newsButton addTarget:self
action:@selector(switchToNewsDetails)
forControlEvents:UIControlEventTouchUpInside];
</pre></code>

and I would like to pass parameters to my selector "switchToNewsDetails".
The only thing I succeed in doing is to pass the (id)sender by writing:
<pre><code>action:@selector(switchToNewsDetails:)</pre></code>

But I am trying to pass variables like integer values. Writing it this way doesn't work :

<pre><code>int i = 0;
[newsButton addTarget:self
action:@selector(switchToNewsDetails:i)
forControlEvents:UIControlEventTouchUpInside];
</pre></code>

Writing it this way does not work either:

<pre><code>int i = 0;
[newsButton addTarget:self
action:@selector(switchToNewsDetails:i:)
forControlEvents:UIControlEventTouchUpInside];
</pre></code>

Any help would be appreciated :)

See my comment above, and I believe you have to use NSInvocation when there is more than one parameter

more information on NSInvocation here

[To see links please register here]

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
}

Target-Action allows three different forms of action selector:

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

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.

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

I was creating several buttons for each phone number in an array so each button needed a different phone number to call. I used the setTag function as I was creating several buttons within a for loop:

for (NSInteger i = 0; i < _phoneNumbers.count; i++) {

UIButton *phoneButton = [[UIButton alloc] initWithFrame:someFrame];
[phoneButton setTitle:_phoneNumbers[i] forState:UIControlStateNormal];

[phoneButton setTag:i];

[phoneButton addTarget:self
action:@selector(call:)
forControlEvents:UIControlEventTouchUpInside];
}

Then in my call: method I used the same for loop and an if statement to pick the correct phone number:

- (void)call:(UIButton *)sender
{
for (NSInteger i = 0; i < _phoneNumbers.count; i++) {
if (sender.tag == i) {
NSString *callString = [NSString stringWithFormat:@"telprompt://%@", _phoneNumbers[i]];
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:callString]];
}
}
}

As there are many ways mentioned here for the solution, Except category feature .

> Use the category feature to extend defined(built-in) element into your
> customisable element.

For instance(ex) :




@interface UIButton (myData)

@property (strong, nonatomic) id btnData;

@end

in the your view Controller.m


#import "UIButton+myAppLists.h"

UIButton *myButton = // btn intialisation....
[myButton set btnData:@"my own Data"];
[myButton addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];

Event handler:

-(void)buttonClicked : (UIButton*)sender{
NSLog(@"my Data %@", sender. btnData);
}

This fixed my problem but it crashed unless I changed

action:@selector(switchToNewsDetails:event:)

to

action:@selector(switchToNewsDetails: forEvent:)

I subclassed UIButton in CustomButton and I add a property where I store my data. So I call method: (CustomButton*) sender and in the method I only read my data sender.myproperty.

Example CustomButton:

@interface CustomButton : UIButton
@property(nonatomic, retain) NSString *textShare;
@end

Method action:

+ (void) share: (CustomButton*) sender
{
NSString *text = sender.textShare;
//your work…
}

Assign action

CustomButton *btn = [[CustomButton alloc] initWithFrame: CGRectMake(margin, margin, 60, 60)];
// other setup…

btnWa.textShare = @"my text";
[btn addTarget: self action: @selector(shareWhatsapp:) forControlEvents: UIControlEventTouchUpInside];