Question

I have an IPhone application in which i want to change the background image of the button each time when it is tapped,ie if it follow it needs to be unfollow when it is tapped and viceverse.Can anybody help me?

Answer 1

@interface XXX: UIViewController // whatever
{
    BOOL btnImageState;
}

// etc.

@implementation XXX

- (id)init
{
    if ((self = [super init]))
    {
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
        [btn setImage:[UIImage imageNamed:@"follow.png"] forState:UIControlStateNormal];
        [btn setFrame:CGRectMake(x, y, w, h)];
        [btn addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];
        [self.view addSubview:btn];
    }
    return self;
}

- (void)click:(UIButton *)btn
{
    if (btnImageState)
        [btn setImage:[UIImage imageNamed:@"follow.png"] forState:UIControlStateNormal];
    else
        [btn setImage:[UIImage imageNamed:@"unfollow.png"] forState:UIControlStateNormal];

    btnImageState = !btnImageState;
}

@end