If your app doesn't implement any splash screen, it is implemented by default in Android 12 (API level 31). In other words, there is a splash screen for Android 12 or later but not for Android 11 and older Android version.

To stay consistent with the older Android version to have a similar default splash screen, you can follow this step-by-step guide to implement the splash screen.

1. Add Splash Screen Library

Add androidx.core:core-splashscreen library in build.gradle.

dependencies {
   implementation 'androidx.core:core-splashscreen:1.0.0'
}

2. Add Splash Screen Style

Add this splash.xml in your res/values folder. It can be any name you wish. You can also use the existing themes.xml if you have it.

<resources>
    <style name="Theme.App.Starting" parent="Theme.SplashScreen">
        <item name="windowSplashScreenBackground">#ff616161</item>
        <item name="windowSplashScreenAnimatedIcon">@drawable/ic_android_kotlin_weekly</item>
        <item name="postSplashScreenTheme">@android:style/Theme.Material.Light.NoActionBar</item>
    </style>
</resources>

• Set the theme style parent to Theme.SplashScreen

• Set windowSplashScreenBackground to your app primary color

• Set windowSplashScreenAnimatedIcon to your app icon asset

• Set postSplashScreenTheme to your original theme style for your app

Please note that I hard code the color instead of using @color/... because I have gotten rid of this colors.xml completely in this clean compose app template.

In fact, I think we shouldn't need to have this splash.xml at all for Jetpack Compose app.

3. Update Application Theme Style

In AndroidManifest.xml, update application android:theme

<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <application
        android:theme="@android:style/Theme.Material.Light.NoActionBar">
    </application>
</manifest>

with @style/Theme.App.Starting that you created in splash.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <application
        android:theme="@style/Theme.App.Starting">
    </application>
</manifest>

4. Call installSplashScreen() in Activity

In your activity, call the installSplashScreen(), before you call the Acitivty.onCreate() base class.

To decide how long the splash screen stay, you can call SplashScreen.setKeepOnScreenCondition() which allows you to implement KeepOnScreenCondition interface using SAM conversion.

This is an example of what I did for my rss feed reader app

    override fun onCreate(savedInstanceState: Bundle?) {

        setupSplashScreen()

        super.onCreate(savedInstanceState)
        /*...*/
    }

    private fun setupSplashScreen() {
        var keepSplashScreenOn = true
        lifecycleScope.launch {
            lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
                viewModel.uiState.collect { uiState ->
                    keepSplashScreenOn =
                        uiState is ArticlesUiState.Loading ||
                        uiState is ArticlesUiState.Invalid
                }
            }
        }

        installSplashScreen().setKeepOnScreenCondition {
            keepSplashScreenOn
        }
    }

Summary

Your app now should have the splash screen in all Android versions. This is a default splash screen implementation which is pretty simple. For more details, you can refer to this official guide.

If the splash screen doesn't work, you may want to make sure your app is completely killed because the splash screen is NOT shown during hot start. This seems to happen in API 33 where pressing the back button doesn't kill the app. It is still in the background.

Reference

Code Changes Example: Diff(Android News) and Diff(Template App)