Reference a UIImageView control using a string in XCODE

Question

I have about 10 UIImageView controls named pop1 to pop10.

I have 10 buttons each over a UIImageView. The buttons have a "tag" from 1 to 10 so I know which button is being pressed by:

UIButton * aButton =(UIButton *)sender;
aButton.tag - gives me the tag

I want to reference the UIImageView under the button to change its image when the button above it is pressed:

UIImage *image = [UIImage imageNamed: @"NewImage.png"];
[pop1 setImage:image];

But in the above code I do not want to hardcode the "pop1" or "pop2" etc. I want to build a string using the button tag

NSString *img = [NSString stringWithFormat:@"pop%d",aButton.tag];

gives me "pop1" or "pop2" etc, since I am using the aButton.tag.

So using this info how can I write code to reference the UIImage to change its image?

In his line, the "pop1" needs to be changed so it uses the built string - img:

[pop1 setImage:image];

I do NOT want to have to type in a switch statement for each tag as later on I intend to add a large number of such controls and that is not an option.

Is there a way or is there any other approach I can use?

Update

I tried the answer given by John in code like this

-(IBAction)pop:(id)sender{
  UIButton * aButton =(UIButton *)sender;
  NSLog(@"clicked button with TAG %d",aButton.tag);

  if (aButton.tag > 0) {
    UIImageView *img = (UIImageView *)[self.view viewWithTag:aButton.tag];

    UIImage *ix = [UIImage imageNamed:@"Newimage.png"];

    [img setImage:ix];
    // stop any more clicks
    aButton.tag = 0;
  }    


}

Everything builds ok but on running, I get an error because "img" shows up in the debug window as a "UIButton" not a UIImage ( i think).

I am totally puzzled by this as in IB the control shows up as Class:UIImageView yet in code I am referencing it as UIImage? Are they interchangable?

How do I access the "tag" property of the "UIImageView - Displays a single image or animation described by an array of images(help)"

Bascically the buttons also have a tag so if button 2 is clicked it's tag is 2. So I want to change the image of UIImageView with tag = 2 and so on.

I am currently learning C/C and such a simple task in most other languages is so tedious in this.

I am at a loss. Help please.

Answer 1

give UIImageView tag -1 to -10 then replace pop function with:

-(IBAction)pop:(id)sender{
  UIButton * aButton =(UIButton *)sender;
  NSLog(@"clicked button with TAG %d",aButton.tag);

  if (aButton.tag > 0) {
    UIImageView *img = (UIImageView *)[self.view viewWithTag:(aButton.tag*-1)];

    UIImage *ix = [UIImage imageNamed:@"Newimage.png"];

    [img setImage:ix];
    // stop any more clicks

  }    
}

Answer 2

Put tags on the associated views - say 101-110 then take the button tag, add 100 to it and then call viewWithTag with that number...

Answer 3

i suggest you to use UIButton instead of UIImageView. set your image as your buttons image, and give them tags, however this will make your user click on the image instead of a separated button.

Answer 4

You can iterate over the subviews of a view and get to each UIImageView that way. However, be aware that using a big number of images will quickly get you to trigger memory warnings on mobile devices, so use wisely.