Question

-(IBAction)startClick:(id)sender{
 stick.highlighted = YES;
}

-(void)viewDidLoad{  
 [super viewDidLoad];  
 stick = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"ball1.png"]];
 stick.userInteractionEnabled= YES;

 stick.highlightedImage = [UIImage imagedNamed:@"ball2.png"];
 [self.view addSubview:stick]; 
}

Button does not work after i type viewDidLoad method. Pls help. Thx. stick is linked to a uiimageview.

Answer 1

Hello as you said stick is linked to UIImageView , then it is a bit ambiguous. It’s not clear whether you have declared an IBOutlet for this and connected to an UIImageview in xib or you have declared it as a variable in header file . There are two methods both of which works fine

Method 1:

Declare an IBoutlet in .h file and connect it to an Imageview in xib . Calling methods as follows

-(void)viewDidLoad{  
    [super viewDidLoad];  
    stick.image = [UIImage imageNamed:@"firstImage.png"];
    stick.highlightedImage = [UIImage imageNamed:@"secondImage.png"];
}

-(IBAction)startClick:(id)sender{
    stick.highlighted = YES;
}

would serve your purpose. The method is called from a button in xib on touch up inside event. In case you want to call this method from bar button all you need is to hook up selector of bar button to startclick method.

//2nd Method

If you have declared your Imageview in header as UIImageView* stick;

in viewDidLoad method you need to allocate it as

-(void)viewDidLoad{  
    [super viewDidLoad];  

    if (!stick) {
        stick = [[UIImageView alloc] initWithFrame:CGRectMake(50, 50, 100, 100)];
        [stick setImage:[UIImage imageNamed:@"firstImage.png"]];
        [stick setHighlightedImage:[UIImage imageNamed:@"secondImage.png"]];
    }

    UIBarButtonItem* barButton = [[UIBarButtonItem alloc] initWithTitle:@"Click" style:UIBarButtonItemStylePlain 
                                                                 target:self action:@selector(startClick:)];
    self.navigationItem.rightBarButtonItem = barButton;
    [barButton release];

}

-(void)startClick:(id)sender{
    stick.highlighted = YES;
}

Hope it helps !!