Sample Weather Compose

This projects contains an Android weather application, developed with the new UI framework Jetpack Compose. The goal is to highlight the most innovative features and the improved developer experience compared to the View & XML approach in Android.

Contents of this project are used to present Jetpack Compose, and its opportunities for app development, at conferences or other tech orientated sessions.

The project contains a small amount of business logic within the domain package. Inside the ui package resides all of the Jetpack Compose implementation, which is the major part of the application source code.

Dynamic Theming

The app demonstrates how easy it is to develop a dynamic application theming using Compose foundation APIs. With a few lines of code you can make your theme customizable by any app user:

@Composable
fun WeatherApp() {
    var activeColorPalette by remember { mutableStateOf(ColorPalettes.DarkBlue) }
    var activeDimensionScale by remember { mutableStateOf(1.0f) }
    
    WeatherTheme(
        colorPalette = activeColorPalette,
        dimensionScale = activeDimensionScale
    ) {
        AppContent(
            onColorPaletteSelected = { activeColorPalette = it },
            onSizeSelected = { activeDimensionScale = it}
        )
    }
}

You can find the dynamic theme implementation within the WeatherActivity inside the de.eso.weather.ui package.

Slot APIs

Jetpack Compose leverages designing UI elements with dynamic content to the next level. What was previously a pain to implement is now straight forward by using slot APIs.

For example for individual content of a Button:

Button(onClick = { }) {
    Image(Icons.Filled.Brush, null)
}

Button(onClick = { }) {
    Text("Sunshine")
}

Button(onClick = { }) {
    Image(Icons.Filled.Brush, null)
    Text("Sunshine")
}

Android Studio Previews

With Jetpack Compose it is very simple to create a preview in Android Studio for all of your UI elements.

You can also take it a step further and create a @Preview for entire app screens, with different style characteristics: