What's new in Compose Multiplatform 1.7.1

Minimum AGP version raised to 8.1.0

Neither Jetpack Compose 1.7.0 nor Lifecycle 2.8.0, which are both used by Compose Multiplatform 1.7.0, supports AGP 7. So, when you update to Compose Multiplatform 1.7.1, you may have to upgrade your AGP dependency, as well.

Java resources API is deprecated in favor of the multiplatform resource library

In this release, we explicitly deprecate the Java resources APIs available in the compose.ui package: the painterResource(), loadImageBitmap(), loadSvgPainter(), and loadXmlImageVector() functions, as well as the ClassLoaderResourceLoader class and functions relying on it.

Consider transitioning to the multiplatform resource library. While you can use Java resources with Compose Multiplatform, they don't benefit from extended features provided by the framework: generated accessors, multimodule support, localization and so on.

If you still have to access Java resources, you can copy the implementation suggested in the pull request to make sure your code works even after you upgrade to Compose Multiplatform 1.7.1 and switch to multiplatform resources where possible.

New default behavior for processing touch in iOS native elements

Before 1.7.1, Compose Multiplatform could not respond to touch events that landed in interop UI views, so interop views handled these touch sequences entirely.

Compose Multiplatform 1.7.1 implements more sophisticated logic for handling interop touch sequences. By default, there is now a delay after the initial touch, which helps the parent composable understand whether the touch sequence was meant to interact with the native view and react accordingly.

For more information, see the explanation in the iOS section of this page or read the documentation for this feature.

Disabling minimum frame duration on iOS is mandatory

Developers often failed to notice the printed warning about the high refresh rate displays, and users were deprived of smooth animations on their 120-Hz-enabled devices. We are now strictly enforcing this check. Apps built with Compose Multiplatform will now crash if the CADisableMinimumFrameDurationOnPhone property in the Info.plist file is absent or set to false.

You can disable this behavior by setting the ComposeUIViewControllerConfiguration.enforceStrictPlistSanityCheck property to false.

Deprecated Modifier.onExternalDrag on desktop

The experimental Modifier.onExternalDrag and related APIs have been deprecated in favor of the new Modifier.dragAndDropTarget. The DragData interface was moved into the compose.ui.draganddrop package.

If you are using the deprecated APIs with Compose Multiplatform 1.7.0, you are going to encounter a deprecation error. With 1.8.0 the onExternalDrag modifier is going to be removed altogether.

Shared element transitions

Compose Multiplatform now offers an API for seamless transitions between composables that share consistent elements. These transitions are often useful in navigation, helping users follow the trajectory of changes in the UI.

For a deep dive into the API, see the Jetpack Compose documentation.

Type-safe Navigation

Compose Multiplatform has adopted Jetpack Compose’s type-safe approach to passing objects along a navigation route. New APIs in Navigation 2.8.0 allow Compose to provide compile-time safety for your navigation graph. These APIs achieve the same result as the Safe Args plugin for XML-based navigation.

For details, see Google’s docs about type safety in Navigation Compose.

Multiplatform resources

Resources packed into Android assets

All multiplatform resources are now packed into Android assets. This allows Android Studio to generate previews for Compose Multiplatform composables in Android source sets.

This also offers direct access to multiplatform resources from WebViews and media player components on Android, since resources can be reached by a simple path, for example, Res.getUri(“files/index.html”).

Here's an example of an Android composable that displays a resource HTML page with a link to a resource image:

// androidMain/kotlin/com/example/webview/App.kt @OptIn(ExperimentalResourceApi::class) @Composable @Preview fun App() { MaterialTheme { val uri = Res.getUri("files/webview/index.html") // Adding a WebView inside AndroidView with layout as full screen. AndroidView(factory = { WebView(it).apply { layoutParams = ViewGroup.LayoutParams( ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT ) } }, update = { it.loadUrl(uri) }) } }

The example works with this simple HTML file:

<html> <header> <title> Cat Resource </title> </header> <body> <img src="cat.jpg"> </body> </html>

Both resource files in this example are located in the commonMain source set:

New common modules

Skia updated to Milestone 126

The version of Skia used by Compose Multiplatform, via Skiko, has been updated to Milestone 126.

The previous version of Skia used was Milestone 116. You can see the changes made between these versions in the release notes.

GraphicsLayer – a new drawing API

The new drawing layer added in Jetpack Compose 1.7.0 is now available in Compose Multiplatform.

Unlike Modifier.graphicsLayer, the new GraphicsLayer class allows you to render Composable content anywhere. It is useful in cases where animated content is expected to be rendered in different scenes.

See the reference documentation for a more detailed description and examples.

LocalLifecycleOwner moved out of Compose UI

The LocalLifecycleOwner class has been moved from the Compose UI package to the Lifecycle package.

This change allows you to access the class and call its Compose-based helper APIs independently of a Compose UI. Keep in mind, however, that without the Compose UI bindings, a LocalLifecycleOwner instance will have no platform integration and thus no platform-specific events to listen to.

Improved touch interop between Compose Multiplatform and native iOS

This release improves touch handling for iOS interop views. Compose Multiplatform now tries to detect whether a touch is meant for an interop view or should be processed by Compose. This makes it possible to process touch events that happen in a UIKit or a SwiftUI area inside your Compose Multiplatform app.

By default, Compose Multiplatform will delay transmitting touch events to interop views by 150 ms:

• If within this time frame there is movement over a distance threshold, the parent composable will intercept the touch sequence, and it will not be forwarded to the interop view.

• If there is no noticeable movement, Compose will not process the rest of the touch sequence, which will instead be processed solely by the interop view.

This behavior aligns with how the native UIScrollView works. It helps prevent situations where a touch sequence that starts in the interop view is intercepted without a chance for Compose Multiplatform to process it. This could lead to a frustrating user experience. For example, imagine a large interop video player used in a scrollable context such as a lazy list. It is tricky to scroll the list when most of the screen is taken up by a video that intercepts all touches without Compose Multiplatform being aware of them.

Native performance improvements

With Kotlin 2.0.20, the Kotlin/Native team made a lot of progress in making Compose apps on iOS perform faster and smoother. Compose Multiplatform 1.7.1 release makes use of these optimizations, as well as brings performance improvements from Jetpack Compose 1.7.0.

When comparing Compose Multiplatform 1.6.11 paired with Kotlin 2.0.0 and Compose Multiplatform 1.7.1 paired with Kotlin 2.0.20, we see better results across the board:

• The LazyGrid benchmark simulates LazyVerticalGrid scrolling, which is closest to real-life use cases, and performs ~9% faster on average. It also shows significantly reduced number of missed frames, which usually make the users perceive the UI as less responsive. Try it out for yourself: apps made with Compose Multiplatform for iOS should feel much smoother.

• The VisualEffects benchmark renders a lot of randomly placed components and works 3.6 times faster: average CPU time per 1000 frames was reduced from 8.8 seconds to 2.4.

• The AnimatedVisibility composable animates showing and hiding an image and demonstrates ~6% faster rendering.

On top of that, Kotlin 2.0.20 introduces experimental support for concurrent marking in the garbage collector. Enabling concurrent marking shortens garbage collector pauses and leads to even bigger improvements for all benchmarks.

You can check out the code for these Compose-specific benchmarks in the Compose Multiplatform repository:

• Kotlin/Native performance benchmark

• Kotlin/JVM versus Kotlin/Native benchmark

Drag and drop

The drag-and-drop mechanism, which enables users to drag content into or out of your Compose application, has been implemented in Compose Multiplatform for desktop. To specify potential sources and destinations for dragging and dropping, use the dragAndDropSource and dragAndDropTarget modifiers.

For common use cases, see the dedicated article in the Jetpack Compose documentation.

BasicTextField, renamed from BasicTextField2, adopted on desktop

Jetpack Compose has made the BasicTextField2 component stable and renamed it BasicTextField. In this release, Compose Multiplatform has adopted the change for desktop targets, and there are plans to cover iOS as well in the stable 1.7.0 version.

The new BasicTextField:

• Allows you to manage state more reliably.

• Offers the new TextFieldBuffer API for programmatic changes to text field content.

• Includes several new APIs for visual transformations and styling.

• Provides access to UndoState with the ability to return to previous states of the field.

Render settings for ComposePanel

By specifying the new RenderSettings.isVsyncEnabled parameter in the ComposePanel constructor, you can hint to the backend rendering implementation to disable vertical synchronization. This can reduce visual latency between inputs and changes in the UI but can also lead to screen tearing.

The default behavior stays the same: The ComposePanel attempts to synchronize drawable presentations with VSync.

skiko.js is redundant for Kotlin/Wasm applications

The skiko.js file is now redundant for Kotlin/Wasm applications built with Compose Multiplatform. You can remove it from the index.html file and improve the load times of your app. skiko.js will be removed from the Kotlin/Wasm distribution completely in future releases.