Prevent UIStepper from being 0?

I have a UIStepper that has a stepValue of 1. I would like the UIStepper to be able to be positive or negative up until its maximum and minimum values, but never 0.

Every attempt I have made at solving this is unable to account for whether the stepper was decreasing or increasing (thus should skip 0 to 1 or to -1). The only other thing I can think of is saving the previous value and comparing, but that sounds a little involved for such a simple task.

Any ideas? Has anyone else ran into the same requirements?

Solution

I would approach this from a different direction. Let the stepper do what it does, and just change your interpretation of it.

For example, if you have a stepper that you want to go from -5 to +5 but skipping 0:

Set stepper minumum to -5.
Set stepper maximum to 4.
Set stepper stepValue to 1.
When you read the stepper value, add 1 if value is non-negative:
```
let value = stepper.value + (stepper.value < 0 ? 0 : 1)
```

When you set the stepper value, first lower the positive values by 1:

// value of 3 will be represented in the stepper by 2
value = 3
stepper.value = value - (value > 0 ? 1 : 0)

Hide the details with a nonZeroValue computed property

You can hide these +1 and -1 adjustments by creating an extension to UIStepper that adds a new computed property called nonZeroValue.

extension UIStepper {
    var nonZeroValue: Double {
        get {
            return self.value + (self.value < 0 ? 0 : 1)
        }
        set {
            self.value = newValue - (newValue < 0 ? 0 : 1)
        }
    }
}

Then, just use stepper.nonZeroValue in place of stepper.value in your code.