Why Compose with existing Views (interop) in Android Kotlin? - Purpose & Use Cases

The Big Idea

What if you could add shiny new UI parts without breaking your whole app?

The Scenario

Imagine you have an Android app with many screens built using old Views like Buttons, TextViews, and RecyclerViews. Now you want to add new, modern UI parts using Jetpack Compose without rewriting everything.

The Problem

Rebuilding the whole app from scratch is slow and risky. Mixing old Views and new Compose UI manually means writing complex code to manage both, which is error-prone and hard to maintain.

The Solution

Compose with existing Views interop lets you smoothly combine Compose UI and traditional Views in the same screen. You can reuse old Views inside Compose or add Compose UI inside View layouts easily.

Before vs After

✗ Before

val oldButton = findViewById<Button>(R.id.old_button)
oldButton.setOnClickListener { /* handle click */ }

✓ After

AndroidView(factory = { context -> Button(context).apply { setOnClickListener { /* handle click */ } } })

What It Enables

You can modernize your app step-by-step, mixing new Compose UI with existing Views without rewriting everything.

Real Life Example

A shopping app wants to add a fancy Compose-based product card but keep the old cart screen built with Views. Interop lets both UI styles work together seamlessly.

Key Takeaways

Old Views and new Compose UI can live together smoothly.

No need to rewrite entire app to use Compose.

Interop saves time and reduces bugs when mixing UI types.