Question

The button is not a UIButton, it’s a subclass of UIControl

When the user taps my UIControl, I want to change the alpha so the user has some visual feedback that it’s being pressed. Then change it again when released

UIImageView *mask =[[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 58, 58)];
mask.image =[UIImage imageNamed:@"centerButton.png"];
mask.center = self.center;
mask.center = CGPointMake(mask.center.x, mask.center.y+3);
[self addSubview:mask];

The center button was created using a tutorial on rayWenderlich.com for learning about creating custom controls.

I’m stuck. I can’t figure out how to reference the center image.

Here is my .h class

@interface OOTRotaryWheel : UIControl


@property (weak) id <OOTRotaryProtocol> delegate;
@property (nonatomic, strong) UIView *container;
@property int numberOfSections;
@property CGAffineTransform startTransform;
@property (nonatomic, strong) NSMutableArray *sectors;
@property int currentSector;
@property (nonatomic, retain) UIImageView *mask;

- (id) initWithFrame:(CGRect)frame andDelegate:(id)del withSections:(int)sectionsNumber;
- (void)rotate;
- (void) buildSectorsEven;
- (void) buildSectorsOdd;

@end

So how do I detect a touch down on the UIImageView and touch up? and make it more like a button (so when i can load another xib or something)

Answer 1

To change the alpha use: mask.alpha = 0.0f;

To do this with IBActions:
To act when the button is pressed:

-(IBAction)buttonPressedDown{
      mask.alpha = 0.5f;
}//Connect this IBAction to touchDown

To change the button back to it’s original Alpha:

-(IBAction)buttonUpInsideAndOutside{
      mask.alpha = 1.0f;
}//Connect this IBAction to touchUpInside and touchUpOutside

---

To do this with UITouches:
To act when the button is pressed:

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
      UITouch*touch = [touches anyObject];
      if(touch.view==mask)
            mask.alpha = 0.5f;
}//Will only work if the IBOutlet is connected

To change the button back to it’s original Alpha:

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
      mask.alpha = 1.0f;
}//Will only work if the IBOutlet is connected

This will work, wether you have a xib/storyboard interface or not.