From Xojo Documentation
The Slider control provides an interface that is used for increasing or decreasing a numeric value. The Slider can only be displayed horizontally.
You can use the Set Default Value feature to set the default position of the slider.
Below is a list of commonly used events and properties. Refer to MobileSlider in the Language Reference for the complete list.
ValueChanged- Called when the Slider value changes, either by the user adjusting the Slider or by code changing its Value property.
Enabled - A boolean that indicates if the slider is enabled and can be adjusted or disabled and cannot be adjusted.
MaximumValue - The maximum Double value for the slider.
MinimumValue - The minimum Double value for the slider.
Value - An Double value that indicates the position of the Slider. If Value is assigned a value less than MinimumValue, then MinimumValue is used. If Value is assigned a value greater than MaximumValue, then MaximumValue is used.
To have a Slider update a Label with its Value as the Slider is adjusted, you can put this code in the Slider's ValueChanged event handler: