Question

I have two UISliders that both have value range of 1 to 8.
When app starts slider1 is at value 1 and slider2 is at value 8. When slider1 is moved to value 2, I want slider2 to move to value 7 automatically. So when one slider value goes up, the other slider value comes down.

How do I link these sliders together?

Answer 1

Well. I created my own little app and easily implemented the ability. Here’s how. What you need to do is connect an action to each of your sliders. That action will get called each time the value changes. Inside each action. Do something like this. In .m

@synthesize slider1;
@synthesize slider2;

...

- (IBAction)slider2DidChange:(id)sender {
    NSLog(@"Value did change");
    int value = [slider2 value];
    NSLog(@"%d", value);
    int newValue = 8 - value;
    [slider1 setValue:newValue animated:YES];
}

- (IBAction)slider1DidChange:(id)sender {
    NSLog(@"Value did change");
    int value = [slider1 value];
    NSLog(@"%d", value);
    int newValue = 8 - value;
    [slider2 setValue:newValue animated:YES];
}

Of course, that also requires that you have four connections.

@property (assign) IBOutlet UISlider *slider1; //Connect to slider1
@property (assign) IBOutlet UISlider *slider2; //Connect to slider2


- (IBAction)slider2DidChange:(id)sender; //Connect action to slider2
- (IBAction)slider1DidChange:(id)sender; //Connect action to slider1

That’s it. I am going to post my little app to Infinite Open Syntax and will supply the link shortly. That way you can download the source and took a look yourself. Cheers!