Two Ways to Build Android UIs

For most of Android's history, building a user interface meant writing XML layout files, inflating them in Activities or Fragments, and manipulating views imperatively in code. Jetpack Compose, Google's modern UI toolkit introduced in stable form in 2021, flips that model entirely — you describe what the UI should look like based on state, and the framework handles the rest.

If you're starting a new project or considering migrating an existing one, you need to weigh both approaches honestly.

How XML Layouts Work

The traditional approach uses separate XML files to define the view hierarchy, which is then inflated at runtime. UI logic lives in Kotlin/Java code, and you update individual views by referencing them — either via findViewById or view binding.

Strengths of XML layouts

  • Mature ecosystem: Years of Stack Overflow answers, tutorials, and battle-tested patterns.
  • Visual editor: Android Studio's Layout Editor provides a drag-and-drop WYSIWYG experience.
  • Performance on older devices: XML inflation is well-optimized and predictable.
  • Existing codebase compatibility: No migration needed if you're maintaining a legacy app.

Weaknesses

  • Verbose and often repetitive XML.
  • State management can get complicated (Fragments, ViewModels, LiveData all in play).
  • Tight coupling between layout and logic can make testing harder.

How Jetpack Compose Works

Compose is a declarative UI framework. You write composable functions in Kotlin that describe the UI based on the current state. When state changes, Compose automatically recomposes only the affected parts of the UI.

@Composable
fun Greeting(name: String) {
    Text(text = "Hello, $name!")
}

Strengths of Jetpack Compose

  • Less code: Composables are significantly more concise than equivalent XML + boilerplate.
  • Unified language: UI and logic are both in Kotlin — no context-switching between XML and code.
  • Better state management: Compose is designed around state, making data flow more predictable.
  • Easier testing: Composables are plain functions and compose test utilities are excellent.
  • Animations: The animation APIs in Compose are more intuitive than the XML animator system.

Weaknesses

  • Steeper initial learning curve, especially understanding recomposition.
  • Some third-party libraries haven't fully migrated to Compose-native versions.
  • Build times can be longer due to Kotlin compiler plugins.
  • Previews in Android Studio, while improving, can be slower than the XML Layout Editor.

Interoperability: You Don't Have to Choose All at Once

One of the best features of Compose is that it's designed to work alongside XML. You can embed a composable inside an XML layout using ComposeView, or embed a traditional view inside Compose using AndroidView. This means migration can be incremental — you don't need to rewrite everything overnight.

Which Should You Choose?

Scenario Recommendation
New greenfield app Jetpack Compose
Large existing codebase Incremental Compose adoption
Team unfamiliar with Compose Start with XML, plan migration
App targeting API 21+ Compose is fully compatible
Complex custom animations Compose animation APIs shine here

The Verdict

For any new Android project today, Jetpack Compose is the right default choice. Google has made clear it's the future of Android UI development, tooling continues to improve rapidly, and the developer experience is genuinely better once you get past the learning curve. For existing apps, adopt Compose incrementally — start with new screens and work backwards.

XML layouts aren't going anywhere soon, but the momentum is unmistakably with Compose.