Question

I think I’ve followed sample code to the letter, but the below is giving me an error.

I want to subclass UIButton and add a couple of properties, but I’m failing from the get-go.

I have created a subclass file. these are my .h/.m’s:

// damButton.h
#import <UIKit/UIKit.h>

@interface damButton : UIButton
{
    CGFloat _position;
}
@property (nonatomic) CGFloat position;
@end

and

// damButton.m
#import "damButton.h"

@implementation damButton

@synthesize position = _position;

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
    }
    return self;
}
@end

in my mainviewcontroller, I have imported my custom button, but when I use the property’s inbuilt getter and setter, I get an error:

//MainViewController.m
#import "damButton.h"

// then within a method...
damButton *b = [damButton buttonWithType:UIButtonTypeRoundedRect];
[b position:5.0];

generates this error: No visible @interface for 'damButton' declares the selector 'position:'

I’m not sure what I’m missing here, I’ve pretty much copied it verbatim (I think). I only want to use the inbuilt getters/setters (for now).

What am I missing?

Answer 1

You are calling the getter method, instead of the setter method -setPosition, i.e. try:

[b setPosition:5.0];

or

b.position = 5.0;

May I ask what you’re trying to achieve by subclassing UIButton?