Google I/O 2024: Shared Component Transitions in Jetpack Compose

Google I/O 2024 launched so many thrilling new applied sciences, particularly Gemini AI and Jetpack Compose. Although Jetpack Compose is superior and enhancing quickly to meet up with the legacy XML-based layouts (which have been on the market for ages), it fell brief in some areas, similar to animations.

Shared Component Transitions are among the many hottest APIs from the Android Animation Framework, which wasn’t accessible within the Jetpack Compose till now. That’s proper – Google launched shared component transitions for Jetpack Compose at their 2024 I/O occasion!

This long-awaited characteristic helps you create lovely, fluid animations when navigating between screens in your app. Think about a person tapping a picture in a listing, and it easily expands and animates into the detailed view. Shared component transitions in Compose present a declarative strategy to obtain this impact, supplying you with extra management over the animation course of than the normal View system. This empowers builders to design seamless person experiences that improve their apps’ total appear and feel.

Listed below are among the key capabilities of Shared Component Transitions in Jetpack Compose launched at Google I/O 2024:

• Declarative Animation: Shared component transitions are outlined declaratively utilizing modifiers like Modifier.sharedElement and Modifier.sharedBoundsMatchingContentSize. This animation course of is far less complicated in comparison with the crucial method required within the View system.
• Finer Management: Compose offers extra granular management over the animation in comparison with conventional strategies. You’ll be able to outline the precise component to animate, its transition bounds, and even the animation sort.
• Seamless Integration With Navigation: Shared component transitions work easily with Navigation Compose. When navigating between screens, you’ll be able to go the component’s key as an argument, and Compose routinely matches components and creates the animation.

Getting Began

To make the most of the most recent APIs, be sure to’re utilizing the most recent Android Studio Jellyfish | 2023.3.1 and API Degree 34.

Click on the Obtain Supplies button on the high or backside of this tutorial. Unzip the ComposeTransitionAnimation.zip folder.

Now, launch Android Studio and open ComposeTransitionAnimation-Starter to import the starter challenge. The ComposeTransitionAnimation-Starter challenge accommodates the required boilerplates and Composables to leap straight into the animation!

ComposeTransitionAnimation-Starter resembles an e-commerce app with a fundamental Record-Element structure.

Construct and run the app – it’ll appear to be this:

On this article, you’ll create a visible connection between components on Record and Element screens utilizing Shared Component Transition.

First, add the most recent model of Compose dependencies. Open construct.gradle in your app module and replace:

def composeVersion = "1.7.0-beta01"

Faucet Sync Now to obtain the dependencies.

Observe: Shared component assist is experimental and is in `beta`. The APIs could change sooner or later.

Overview of Key APIs

The newest dependencies launched just a few high-level APIs that do the heavy lifting of sharing components between Composable layouts:

• SharedTransitionLayout: The highest-level structure required to implement shared component transitions. It offers a SharedTransitionScope. A Composable must be in SharedTransitionScope to make use of the modifiers of shared components.
• Modifier.sharedElement(): The modifier to flag one Composable to be matched with one other Composable inside the SharedTransitionScope.
• Modifier.sharedBounds(): The modifier that tells the SharedTransitionScope to make use of this Composable’s bounds because the container bounds for the place the transition ought to happen.

You’ll quickly create a hero-animation utilizing these APIs.

Implementing Shared Transition Animation

A Shared Transition Animation, or hero-animation, consists of three main steps:

1. Wrapping taking part views with SharedTransitionLayout.
2. Defining SharedTransitionScope to the supply and vacation spot views.
3. Transition with Shared Component.

Including SharedTransitionLayout

Open the MainActivity class. It accommodates ListScreen and DetailScreen, which is able to share components throughout a transition animation. As talked about earlier, you need to wrap them with SharedTransitionLayout to make them eligible for a Shared Transition Animation.

Replace the AnimatedContent block as follows:

SharedTransitionLayout {
  AnimatedContent(
    targetState = showDetails, 
    label = "shared_transition"
  ) { shouldShowDetails ->
    if (!shouldShowDetails) {
      ListScreen(
        // Current code
        ... ... ...
      )
    } else {
      DetailScreen(
        // Current code
        ... ... ...
       )
     }
  }
}

At this level, you might even see this warning from Android Studio for utilizing an experimental api:

To resolve this, add these imports on high of the MainActivity:

import androidx.compose.animation.ExperimentalSharedTransitionApi
import androidx.compose.animation.SharedTransitionLayout

Then add this annotation over the onCreate(savedInstanceState: Bundle?) methodology:

@OptIn(ExperimentalSharedTransitionApi::class)

Construct and run.

Defining SharedTransitionScope

Up subsequent, it is advisable to outline SharedTransitionScope to the views taking part within the transition animation. The Composable must be inside SharedTransitionScope to make use of Modifier.sharedElement() for the animation. Therefore, you’ll must go down SharedTransitionScope from SharedTransitionLayout in MainActivity to the supply and vacation spot Composable executing the animation.

On this case, you’ll transition from the smaller Picture Composable within the ListScreen (supply) to the bigger Composable in DetailScreen (vacation spot).

Begin with ListScreen.kt inside ui package deal. Replace the ListScreen perform with these parameters:

@Composable
enjoyable ListScreen(
  paddingValues: PaddingValues,
  objects: Record,
  onItemClicked: (Merchandise) -> Unit = {},
  sharedTransitionScope: SharedTransitionScope,
  animatedVisibilityScope: AnimatedVisibilityScope,
)

Then go the sharedTransitionScope and animatedVisibilityScope references for every ListItem:

objects.forEach { merchandise ->
  ListItem(
    merchandise = merchandise,
    onItemClicked = onItemClicked,
    sharedTransitionScope = sharedTransitionScope,
    animatedVisibilityScope = animatedVisibilityScope,
  )
}

Additionally, replace th eListItem Composable methodology signature accordingly:

@Composable
enjoyable ListItem(
  merchandise: Merchandise,
  onItemClicked: (Merchandise) -> Unit = {},
  sharedTransitionScope: SharedTransitionScope,
  animatedVisibilityScope: AnimatedVisibilityScope,
)

You’ll see the warning for utilizing an experimental api once more from the compiler, together with the errors for the lacking imports.

Fret not! Add these imports on high:

import androidx.compose.animation.AnimatedVisibilityScope
import androidx.compose.animation.ExperimentalSharedTransitionApi
import androidx.compose.animation.SharedTransitionScope

And the annotation for the ListScreen.kt file, above of the package deal title like this:

@file:OptIn(ExperimentalSharedTransitionApi::class)

package deal com.kodeco.android.composetransition.ui

That ensures you might have all the required imports and can mute warnings for utilizing experimental APIs for the scope of the ListScreen.kt file.

Observe: Add the imports and annotation on DetailScreen.kt, too. You’ll want them shortly!

Your vacation spot Composable is the DetailScreen methodology. Now add animation scopes as methodology parameters as follows:

@Composable
enjoyable DetailScreen(
  merchandise: Merchandise, onBack: () -> Unit,
  sharedTransitionScope: SharedTransitionScope,
  animatedVisibilityScope: AnimatedVisibilityScope,
)

You’re able to wire up ListScreen and DetailScreen to carry out the transition animation.

Open MainActivity and replace SharedTransitionLayout block to go animatedVisibilityScope and sharedTransitionScope to its descendants:

SharedTransitionLayout {
  AnimatedContent(
    targetState = showDetails, 
    label = "shared_transition"
  ) { shouldShowDetails ->
    if (!shouldShowDetails) {
      ListScreen(
        paddingValues = paddingValues,
        objects = objects.worth,
        onItemClicked = { merchandise ->
          detailItem = merchandise
          showDetails = !showDetails
        },
        animatedVisibilityScope = this@AnimatedContent,
        sharedTransitionScope = this@SharedTransitionLayout,
      )
    } else {
      DetailScreen(
        merchandise = detailItem,
        onBack = { showDetails = !showDetails },
        animatedVisibilityScope = this@AnimatedContent,
        sharedTransitionScope = this@SharedTransitionLayout,
      )
    }
  }
}

Construct and run once more to make sure you resolved all compilation errors, however don’t count on the animation to occur but!