Jetpack Compose is a modern toolkit for building native Android UI

It was created by Google as a response to the increasing complexity of designing user interfaces for Android apps. With Jetpack Compose, developers can use a declarative and reactive approach to building UI, which makes it easier to create visually stunning and intuitive layouts.

In this blog post, we will cover the following topics:

• What is Jetpack Compose?
• Why was Jetpack Compose created?
• How to set up Jetpack Compose in your Android project
• Coding examples with Jetpack Compose

What is Jetpack Compose?

Jetpack Compose is a declarative and reactive UI toolkit for Android. It allows developers to create UI elements using Kotlin code, rather than XML layout files. This means that developers can write UI code that is more concise, easier to read, and easier to understand.

One of the key benefits of Jetpack Compose is that it follows a declarative programming model. This means that developers specify what they want their UI to look like, rather than specifying how to build it. This makes it easier to create and modify UI elements, as developers only need to worry about the end result, rather than the individual steps needed to achieve it.

Jetpack Compose also follows a reactive programming model, which means that the UI is automatically updated whenever the underlying data changes. This makes it easier to build dynamic and interactive UI, as developers don’t need to manually update the UI when data changes.

Why was Jetpack Compose created?

Jetpack Compose was created as a response to the increasing complexity of designing user interfaces for Android apps. In the past, Android developers had to use a combination of XML layout files and Java/Kotlin code to create their UI. This approach was prone to errors, and it made it difficult to create complex UI layouts.

With Jetpack Compose, Google aims to simplify the process of building UI for Android apps. By using a declarative and reactive programming model, Jetpack Compose makes it easier for developers to create visually stunning and intuitive layouts. It also allows developers to write UI code that is more concise and easier to understand, which makes it easier to maintain and update the UI over time.

How to set up Jetpack Compose in your Android project

To use Jetpack Compose in your Android project, you will need to install the latest version of Android Studio (4.1 or higher). Once you have Android Studio installed, you can follow these steps to set up Jetpack Compose in your project:

Open your Android project in Android Studio. In the build.gradle file for your project, add the following line to the dependencies block:

implementation 'androidx.ui:ui-tooling:0.1.0-dev02'

In the build.gradle file for your app module, add the following lines to the android block:

compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
}

In the AndroidManifest.xml file for your app, add the following attribute to the application element:

android:usesCleartextTraffic="true"

In your app’s main activity, import the following packages:

import androidx.compose.ui.platform.setContent
import androidx.ui.core.Text
import androidx.ui.core.setContent
import androidx.ui.graphics.Color
import androidx.ui.layout.Column
import androidx.ui.layout.Spacing
import androidx.ui.material.MaterialTheme
import androidx.ui.tooling.preview.Preview

In the onCreate method of your main activity, set the content view to a Jetpack Compose UI component:

setContent {
    MaterialTheme {
        // Your Jetpack Compose UI goes here
    }
}

This sets the content view of your activity to a Jetpack Compose UI, which will be rendered in the app when it is run.

Coding examples with Jetpack Compose

Now that you have Jetpack Compose set up in your Android project, let’s look at some coding examples to see how it works in practice.

Example 1: Creating a simple text view The following code creates a simple text view using Jetpack Compose:

Text(text = "Hello, world!")

This will create a text view with the text “Hello, world!” displayed on the screen.

Example 2: Creating a column layout The following code creates a column layout with three text views:

Column {
    Text(text = "Text view 1")
    Text(text = "Text view 2")
    Text(text = "Text view 3")
}

This will create a column layout with three text views, one below the other.

Example 3: Adding styling to a text view The following code creates a text view with custom styling:

Text(
    text = "Hello, world!",
    color = Color.Red,
    style = TextStyle(fontSize = 24.sp)
)

This will create a text view with the text “Hello, world!” displayed in red and with a font size of 24sp.

Example 4: Using a preview function Jetpack Compose includes a preview function that allows you to see a live preview of your UI while you are coding. To use the preview function, add the following code to your file:

@Preview
@Composable
fun Preview() {
    // Your Jetpack Compose UI goes here
}

This will create a preview function that you can use to see a live preview of your UI while you are coding.

I hope this has helped you understand what Jetpack Compose is and how to use it to build native Android UI. With Jetpack Compose, you can use a declarative and reactive approach to building UI, which makes it easier to create visually stunning and intuitive layouts.