Question

I am loading a bunch of images into a UIScrollView, I then resize them and position a button over each, so when I click on the button over the smaller image, it will load up the full size image in a new view.

I am struggling to find a decent way to somehow pass the image’s URL to the click handler as a parameter when the button is clicked, and from what I have read, passing parameters to callback functions is not possible.

Here is the code I have thus far,

for(Card *card in crd){

    pocketImage = [self imageWithImage:[UIImage imageNamed:@"pocket.png"] scaledToSize:CGSizeMake(245/2,80/2)];
    pocketImageView = [[UIImageView alloc] initWithImage:pocketImage];

    cardImage =  [self maskImage:[UIImage imageNamed:@"animal.jpg"]];
    cardImageView = [[UIImageView alloc] initWithImage:cardImage];

    y = (80/2) * inc;

    if (inc % 2){
        x = 125;
    } else {
        x = 10;
        y += (80/2);
    }

    UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
    [btn addTarget:self action:@selector(testMe) forControlEvents:UIControlEventTouchUpInside];
    [btn setFrame:CGRectMake(x,y-40,pocketImageView.frame.size.width,pocketImageView.frame.size.height*2)];

    [pocketImageView setFrame:CGRectMake(x,y,245/2,80/2)];
    [cardImageView setFrame:CGRectMake(x,y-40,245/2,80/2)];

    //add the pocketImageView to the container
    [imageContainer addSubview:cardImageView];
    [imageContainer addSubview:pocketImageView];
    [imageContainer addSubview:btn];

    inc++;
}

Callback function,

-(void)testMe {
    NSLog(@"works");
}

So basically that just loops through all of the images, and then appends all of them to a UIScrollView, which works fine, the problem comes in when I try to pass custom parameters to the testMe method, which isn’t possible as far as I know, so how would I be able to click on the button and then display the corresponding full size image in a new view?

Answer 1

You can use an iVar / (private) @property for this.

Just set the data you want to have available like this:

myTransferVariable = // something you need in you testMe method

and use it like this

-(void)testMe {
    NSLog(@"%@", myTransferVariable);
}