How to make a basic Android app in Kotlin
Android is a widely used mobile operating system that powers millions of smartphones and tablets worldwide. Developers can create original apps for Android devices with the aid of Android Studio. The programming language Kotlin, which utilizes the Java Virtual Machine (JVM) and is officially supported for Android development, is widely used. Here, we will discuss how to make a basic Android app in Kotlin.
Prerequisites
Before diving into Android app development with Kotlin, you’ll need some prerequisite knowledge and equipment, including:
A computer running Windows, macOS, or Linux.
Android Studio installed on the computer.
Basic knowledge of programming concepts and Kotlin syntax.
A physical Android device or an emulator to test the app.
Creating a new project in Android Studio
The first step in creating an Android app in Kotlin is to create a new project in Android Studio. Follow these steps to create a new project:
Open Android Studio.
Click on “Start a new Android Studio project” or go to File > New > New Project.
Select “Empty Activity” and click on “Next.”
Give the project a name and click on “Finish.”
Setting up the user interface
Once the project is created, the next step is to set up the app's user interface (UI) of the app. This involves creating a layout file that defines the visual elements of the app, such as buttons, text fields, and images. Here are the steps to set up the UI:
Open the res folder in the project.
Right-click on the layout folder and select New > Layout Resource File.
Give the layout file a name and select “ConstraintLayout” as the root element.
Drag and drop visual elements from the Palette onto the layout.
Set the properties of each element in the Attributes panel on the right.
Coding the app logic
After setting up the UI, the next step is to code the app’s logic. This involves writing Kotlin code that controls the behavior of the app, such as handling user input and updating the UI. Here are the steps to code the app logic:
Open the
MainActivity.ktfile in the project.Define variables for each visual element in the UI using the
findViewById()function.Write code to handle user input, such as button clicks or text entry.
Write code to update the UI based on user input or other events.
class MainActivity : AppCompatActivity() {private lateinit var button: Buttonprivate lateinit var textView: TextViewoverride fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_main)button = findViewById(R.id.button)textView = findViewById(R.id.textView)button.setOnClickListener {textView.text = "Button clicked"}}}
Testing the app
After coding the app logic, the next step is to test the app on an Android device or emulator. Here are the steps to test the app:
Connect an Android device to the computer or start an emulator.
Click on the “Run” button in Android Studio, or go to Run > Run app.
Select the device or emulator to run the app on.
Wait for the app to build and install on the device or emulator.
Test the app by interacting with the UI and verifying that it behaves as expected.
Conclusion
We covered the prerequisites, created a new project in Android Studio, set up the user interface, coded the app logic, and tested the app. With this knowledge, developers can start building their own custom Android apps using Kotlin.
