Question

I created simple UIScrollView that have images. Each time an image pressed i want to change that image, how can I do it?

I creating this UIScrollView and initializing it with NSMutableArray with images.

      UIScrollView *myScroll = [[UIScrollView alloc] initWithFrame: CGRectMake (0,100,200,30)];
        NSMutableArray = *images = [NSMutableArray alloc] initWithObjects: img1,img2,img3,nil];

for (int i=0; i<3; i++)
{
        UIImageView *imageV = [UIImageView alloc];
        [imageV setImage:[images objectAtIndex:i]];
        [myScroll addSubview:imageV];
        [imageV release];
}


    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget: self action:@selector (changeImg:)];
    [myScroll addGestureRecognizer: singleTap];

and the toucing I’m cathing with the touched place on the scroll:

- (void) singleTapGestureCaptured:(UITapGesturerecongnizer *) gesture
{
    CGPoint touch = [gesture locationInView:myScroll];

}

By X,Y of touched item i know what image was selected

Here I need to change for example the first image of myScroll…How can i do it?

Answer 1

Add UITapGestureRecognizer on UIImageView and set its userInractionEnabled: YES which is NO by default for UIImageView.

UIScrollView *myScroll = [[UIScrollView alloc] initWithFrame: CGRectMake (0,100,200,30)];
NSMutableArray = *images = [NSMutableArray alloc] initWithObjects: img1,img2,img3,nil];

for (int i=0; i<3; i++)
{
    //In your question you didn't set `imageView` frame so correct it
    UIImageView *imageV = [[UIImageView alloc]initWithFrame:yourFrame];
    [imageV setImage:[images objectAtIndex:i]];
    [imageV setUserInteractionEnabled:YES];
    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget: self action:@selector (changeImg:)];
    [imageV addGestureRecognizer: singleTap];
    [myScroll addSubview:imageV];
    [imageV release];
}

After adding all imageView successfully you get them click like this :-

-(void)changeImg:(id)sender
 {
     UIGestureRecognizer *recognizer = (UIGestureRecognizer*)sender;
     UIImageView *imageView = (UIImageView *)recognizer.view;
     [imageView setImage:[UIImage imageNamed:@"anyImage.png"]];
 }