Jetpack Compose vs XML: Why I Switched for My Latest Projects

1. How does Jetpack Compose improve UI rendering performance over XML?

Jetpack Compose is Android's modern declarative UI toolkit that simplifies and accelerates UI development by replacing traditional imperative XML view hierarchies with composable Kotlin functions. For over a decade, Android UI development relied exclusively on imperative XML layout definitions coupled with Java/Kotlin view binding controllers (`findViewById`). As mobile interfaces grew more dynamic, this legacy approach introduced deep view trees, layout inflation overheads, and high boilerplate maintenance.

Google addressed this challenge by introducing Jetpack Compose—a modern, declarative UI toolkit written entirely in Kotlin. Compose allows developers to define layouts programmatically, aligning Android with modern web paradigms like React and Flutter. In this article, I analyze the core differences between Jetpack Compose vs XML, examining rendering mechanics, performance profiles, state management structures, and migration strategies.

2. Declarative vs. Imperative Paradigms

The primary difference between Compose and XML lies in the architectural paradigm. In the imperative XML view model, the layout acts as a stateful tree of view components. When the application state changes, the developer must locate specific views and modify their properties (e.g. textView.setText(newText) or progressBar.setVisibility(View.GONE)). This pattern requires developers to maintain synchronization between the internal program state and the visual display state.

In the declarative Compose model, the UI is stateless. Views are defined as functions marked with the @Composable annotation. These functions accept input state parameters and emit UI elements. When the input state changes, the compose engine automatically runs the functions again with the updated arguments in a process called recomposition.

Let's contrast the syntax for displaying a simple loading state.

The XML Imperative Approach

// layout.xml
<ProgressBar
    android:id="@+id/loadingBar"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:visibility="gone" />

// MainActivity.kt
val progressBar = findViewById<ProgressBar>(R.id.loadingBar)
fun updateLoadingState(isLoading: Boolean) {
    progressBar.visibility = if (isLoading) View.VISIBLE else View.GONE
}

The Jetpack Compose Declarative Approach

// Compose handles state observation and redraws automatically
@Composable
fun LoadingComponent(isLoading: Boolean) {
    if (isLoading) {
        CircularProgressIndicator(
            color = MaterialTheme.colorScheme.primary
        )
    }
}

In the Compose example, there is no manual visibility toggling or view queries. The UI structure naturally reflects the logic state, eliminating view synchronization bugs.

3. State Management: The Single Source of Truth

Compose relies on unidirectional data flow (UDF). States flow down from view models to composable functions, and user interactions (events) flow up to the view models. This pattern aligns with MVVM standards, ensuring data updates originate from a single source of truth.

To preserve values across recompositions, Compose utilizes remember { mutableStateOf(defaultValue) }. When building more complex dashboards, we observe data channels from repository modules using LiveData or Flow and collect them directly inside the composable tree:

// Reactive state tracking within a Compose screen
@Composable
fun DashboardScreen(viewModel: DashboardViewModel) {
    val uiState by viewModel.uiState.collectAsStateWithLifecycle()

    when (val state = uiState) {
        is UiState.Loading -> LoadingIndicator()
        is UiState.Success -> TransactionList(state.data)
        is UiState.Error -> ErrorMessage(state.message)
    }
}

4. Rendering Engine and App Performance

Beyond clean syntax, the differences in under-the-hood rendering mechanics significantly impact Android UI performance.

In the XML view model, the layout system parses XML nodes at runtime, instantiating view classes reflectively. The layout tree then goes through a multi-pass measurement cycle (Measure, Layout, Draw). For deeply nested layouts, this multi-pass cycle causes rendering overhead, occasionally dropping frames (stuttering).

In contrast, Jetpack Compose bypasses the traditional Android View system entirely. Compose draws elements directly onto a hardware-accelerated Canvas using its own internal nodes.

By enforcing a **single-pass layout constraint**, Compose avoids nested measurement performance hits. The compile-time code optimization translates to faster view creation, reducing screen launch delays.

5. Migration Strategy: Integrating Compose with XML

Many engineering teams hesitate to adopt Jetpack Compose because of the size of their legacy codebases. Fortunately, Compose offers excellent interoperability. You don't need to rebuild your application from scratch; instead, you can migrate incrementally using two integration methods:

Method A: Adding Compose Components to XML Views

You can insert a ComposeView node inside an XML file. This allows you to write new, complex components in Compose while retaining the legacy layout skeleton:

// XML File containing a Compose container
<androidx.constraintlayout.widget.ConstraintLayout ...>
    <androidx.compose.ui.platform.ComposeView
        android:id="@+id/composeContainer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</androidx.constraintlayout.widget.ConstraintLayout>

Method B: Embedding XML Views in Compose layouts

For specialized UI components that are not yet natively supported in Compose (such as legacy map frameworks or video players), you can wrap the view in an AndroidView block inside your Composable function tree:

// Embedding a legacy map component in a Compose tree
@Composable
fun LegacyMapView(coordinate: LatLng) {
    AndroidView(
        factory = { context ->
            MapView(context).apply {
                onCreate(Bundle())
            }
        },
        update = { view ->
            view.getMapAsync { map ->
                map.moveCamera(CameraUpdateFactory.newLatLng(coordinate))
            }
        }
    )
}

6. Summary: Key Decisions for My Portfolio Projects

When building SpendWise, using Jetpack Compose enabled me to create a highly responsive dashboard with animated charts and custom Material 3 budget controls in a fraction of the time compared to XML. The single-state flow pattern resolved typical budgeting database sync conflicts.

For GiveEase, the project required a hybrid model: we maintained XML layouts for initial entry sheets while utilizing Compose views for the complex donor-NGO tracking feeds. This verification app confirmed that incremental migration is highly viable.

If you are looking to build a clean local database app or modernize your current view layouts using Jetpack Compose, please explore my featured projects on the Muhammad Saad portfolio home page, or submit an inquiry directly through the contact form.