Multiple interface implementation in Kotlin - Mini Project: Build & Apply

Multiple Interface Implementation in Kotlin

📖 Scenario: Imagine you are building a simple app that manages different types of devices. Each device can perform certain actions like turning on/off and connecting to a network. Some devices can do both, so you need to use multiple interfaces to represent these capabilities.

🎯 Goal: You will create two interfaces Switchable and Connectable, then create a class SmartDevice that implements both interfaces. Finally, you will create an object of SmartDevice and call its methods to see the output.

📋 What You'll Learn

Create an interface called Switchable with two functions: turnOn() and turnOff().

Create an interface called Connectable with one function: connect().

Create a class called SmartDevice that implements both Switchable and Connectable interfaces.

Implement all interface functions in SmartDevice with simple print statements describing the action.

Create an instance of SmartDevice and call all three functions to display their messages.

💡 Why This Matters

🌍 Real World

Many devices and software components have multiple capabilities. Using multiple interfaces helps organize code and reuse functionality.

💼 Career

Understanding multiple interface implementation is important for designing flexible and maintainable software in Kotlin and many other languages.

1

Create the interfaces

Create an interface called Switchable with two functions: turnOn() and turnOff(). Also create an interface called Connectable with one function: connect().

Kotlin

# Define interface Switchable with turnOn() and turnOff() functions
# Define interface Connectable with connect() function
# Your code here

Need a hint?

Use the interface keyword to create interfaces. Define functions without bodies inside them.

2

Create the SmartDevice class

Create a class called SmartDevice that implements both Switchable and Connectable interfaces.

Kotlin

interface Switchable {
    fun turnOn()
    fun turnOff()
}

interface Connectable {
    fun connect()
}

// Create class SmartDevice implementing Switchable and Connectable
// Your code here

Need a hint?

Use a colon : to implement multiple interfaces separated by commas. Use override keyword to provide function bodies.

3

Implement interface functions

Inside the SmartDevice class, implement the functions turnOn(), turnOff(), and connect() to print messages: "SmartDevice is turned on", "SmartDevice is turned off", and "SmartDevice is connecting to network" respectively.

Kotlin

interface Switchable {
    fun turnOn()
    fun turnOff()
}

interface Connectable {
    fun connect()
}

class SmartDevice : Switchable, Connectable {
    // Implement turnOn(), turnOff(), and connect() functions here
    // Your code here
}

Need a hint?

Use println() inside each function to show the messages.

4

Create object and call functions

Create an instance of SmartDevice called device. Then call device.turnOn(), device.connect(), and device.turnOff() to display the messages.

Kotlin

interface Switchable {
    fun turnOn()
    fun turnOff()
}

interface Connectable {
    fun connect()
}

class SmartDevice : Switchable, Connectable {
    override fun turnOn() {
        println("SmartDevice is turned on")
    }

    override fun turnOff() {
        println("SmartDevice is turned off")
    }

    override fun connect() {
        println("SmartDevice is connecting to network")
    }
}

// Create SmartDevice object and call the functions
// Your code here

Need a hint?

Create the object using val device = SmartDevice() and call the functions in order.