🚀 The Pragmatic Guide: Migrating from XML to Jetpack Compose (Step-by-Step)

 A production-grade roadmap to modernizing your Android UI incrementally without breaking your app.

Migrating from XML to Jetpack Compose

The shift from the imperative world of XML to the declarative world of Jetpack Compose is the most significant evolution in Android since the move to Kotlin.

However, a “Big Bang” rewrite is rarely the answer. The secret to a successful migration is interoperability. Here is a future-proof, step-by-step roadmap to modernizing your UI without halting feature development.

🚩 Phase 1: The Foundation (Modern Gradle Setup)

Before writing Composables, you need to sync your environment. In 2026, we lean on the Compose BOM (Bill of Materials) to manage versioning and ensure all libraries play nice together.

In your build.gradle.kts (Module level):

android {
    buildFeatures {
        compose = true
    }

    composeOptions {
        // Tip: Always check the latest compatibility map for your Kotlin version
        kotlinCompilerExtensionVersion = "1.5.11" 
    }
}

dependencies {
    // Manage versions via BOM to avoid dependency hell
    val composeBom = platform("androidx.compose:compose-bom:2025.02.00") 
    implementation(composeBom)
    
    implementation("androidx.compose.ui:ui")
    implementation("androidx.compose.material3:material3")
    implementation("androidx.compose.runtime:runtime-lifecycle-runtime-compose")
}

🏗️ Phase 2: The “Trojan Horse” Strategy (ComposeView)

You don’t need to replace an entire Fragment at once. Use ComposeView to embed a small Compose element directly inside an existing XML layout. This is the gold standard for incremental migration.

Step 1: Add the placeholder to your XML

<androidx.compose.ui.platform.ComposeView
    android:id="@+id/compose_header_container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />

Step 2: Bind it in your Fragment/Activity

binding.composeHeaderContainer.apply {
    // Crucial: This ensures the composition is disposed of correctly
    setViewCompositionStrategy(ViewCompositionStrategy.DisposeOnViewTreeLifecycleDestroyed)
    setContent {
        AppTheme { 
            ModernHeader(title = "Account Settings")
        }
    }
}

🔄 Phase 3: Converting Lists (RecyclerView → LazyColumn)

The RecyclerView is where XML feels heaviest. Moving to LazyColumn eliminates Adapters and ViewHolders entirely.

Pro Tip: To maintain performance, always provide a key. This helps Compose skip unnecessary recompositions when the list changes.

@Composable
fun TransactionList(transactions: List<Transaction>) {
    LazyColumn(
        modifier = Modifier.fillMaxSize(),
        contentPadding = PaddingValues(16.dp)
    ) {
        items(
            items = transactions,
            key = { it.id } // Stable keys for high-performance scrolling
        ) { transaction ->
            TransactionRow(transaction)
        }
    }
}

🧭 Phase 4: Navigation During Migration

Don’t feel pressured to swap out Navigation Component for Navigation Compose on day one. They are highly compatible.

  • Hybrid Approach: Keep your nav_graph.xml. Create a Fragment for your new Compose screen and use ComposeView inside it.
  • Step-by-Step: Migrate individual screens to Fragments-hosting-Compose first. Once a flow is 100% Compose, you can then replace that specific sub-graph with native Navigation Compose.

⚠️ Common Migration Pitfalls (Avoid These!)

Even experienced teams stumble during migration. Keep an eye out for these:

  • The Nesting Trap: Never put a LazyColumn inside a legacy ScrollView or another LazyColumn. This breaks scroll physics and crashes your app.
  • State Leaks: Passing mutable objects (like a User object that gets modified directly) instead of immutable UI state prevents Compose from knowing when to redraw.
  • The Imperative Mindset: Don’t try to “call functions” on a Composable from your Fragment. Instead, update a state in the ViewModel and let the Composable react.

🙋‍♂️ Frequently Asked Questions (FAQs)

Does adding Compose increase my APK size?

Initially, yes. You are shipping two UI toolkits. However, as you remove legacy XML layouts and custom View logic, the size usually levels out. The reduction in code complexity is almost always worth the few extra MBs.

Can I use my existing XML themes in Compose?

While tools like the Accompanist Theme Adapter exist, they are in maintenance mode. For long-term stability, manually map your XML design tokens (colors, typography) into a native MaterialTheme in Compose.

Is Compose faster than XML?

Compose often matches or outperforms XML in complex, deeply nested layouts. However, performance in Compose is a direct result of how you handle state. Use the Layout Inspector to check for excessive recompositions.

💬 Let’s Discuss!

  • Which legacy component in your app is the “final boss” you’re dreading to migrate?
  • For those who have started: Did you find your build times improved or worsened initially?

Drop a comment below — I’d love to hear your migration wins!

📘 Master Your Next Technical Interview

Since Java is the foundation of Android development, mastering DSA is essential. I highly recommend “Mastering Data Structures & Algorithms in Java”. It’s a focused roadmap covering 100+ coding challenges to help you ace your technical rounds.

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