What is a switch in IOS UI?

In IOS, a switch is a user interface (UI) control element that allows users to toggle between two states: on and off. The subclass of UIControl, known as UISwitch, defines the properties and methods that govern the state of a switch.

This is an example of what a switch looks like:

Coding example

This following swift code sets up an outlet connection to a UISwitch object in a user interface file and creates an action method to handle the ValueChanged event of the switch.

Explanation

• Line 1: We use the IBOutlet keyword to declare a property named mySwitch, which is connected to a UISwitch object in the user interface file. The weak keyword indicates that this property is a weak reference, which means that the property does not prevent the referenced object from being deallocated when it is no longer needed.

• Line 2: We use the IBAction keyword to declare a method named switchToggled, which is called when the user toggles the switch. The sender parameter represents the UISwitch object that triggered the event.

• Lines 4–8: The method checks the isOn property of the sender to determine whether the switch is in the "on" or "off" state. If the switch is on, the method executes the code in the if block to perform a specific action. If the switch is off, the method executes the code in the else block to perform a different action.