UIButton disable and enable background image - iphone

Question

My application consist of several buttons , when user touch one of them a shadow appears below them, and the rest of buttons should not have any background image , I need something like Instagram application effects , here is my code but my problem is when I touched other button the shadow does not appears .
#define BGB [btn setBackgroundImage:[UIImage imageNamed:#"shadow.png"] forState:UIControlStateNormal]
#define _BGB [btn setBackgroundImage:nil forState:UIControlStateNormal]
- (IBAction)effectsPerform:(id)sender {
UIButton *btn = (UIButton *)sender;
if (btn == EB0) { BGB; } else { _BGB; }
if (btn == EB1) { BGB; } else { _BGB; }
if (btn == EB2) { BGB; } else { _BGB; }
//and other buttons ...
}

Answer 1

Try this way:
-(void)changeButton:(UIButton *)button background:(UIImage *)image
{
[button setBackgroundImage:image forState:UIControlStateNormal];
}
- (IBAction)effectsPerform:(UIButton *)sender
{
[self changeButton:sender background:(sender == EB0 || sender == EB1 || sender == EB2) ? [UIImage imageNamed:#"shadow.png"] : nil];
}
UPDATE:
You do it with another approach, in your viewDidLoad: method, for every button you can set:
[button setBackgroundImage:nil forState:UIControlStateNormal];
[button setBackgroundImage:[UIImage imageNamed:#"shadow.png"] forState:UIControlStateSelected];
And then in your -(IBAction)effectsPerform:
- (IBAction)effectsPerform:(UIButton *)sender
{
button1.isSelected = (sender == button1);
button2.isSelected = (sender == button2);
....
}
...this way you guarantee you will have only one selected button. What can you do to optimize your code is you can subclass UIButton and in the init method you call the background setter methods, and then all buttons can be of this type (you can mark them in the interface builder by setting their class) - this way you won't need to set the background images for every state for every button.