Use AnimatedContent instead of reinventing the wheel.

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodePresenter.kt

@@ -46,27 +46,16 @@ class ShowQrCodePresenter(
         var qrCodeRotationCounter by remember { mutableIntStateOf(MAX_QR_CODE_ROTATION) }
         val state by produceState(
             initialValue = ShowQrCodeState(
-                data1 = AsyncData.Success(initialData),
-                data2 = AsyncData.Uninitialized,
-                dataToRender = 1,
+                data = AsyncData.Success(initialData),
             )
         ) {
             linkNewMobileHandler.stepFlow.collect { step ->
-                val currentValue = value
                 when (step) {
                     is LinkMobileStep.QrReady -> {
                         loadingJob?.cancel()
-                        if (currentValue.dataToRender == 1) {
-                            value = currentValue.copy(
-                                data2 = AsyncData.Success(step.data),
-                                dataToRender = 2,
-                            )
-                        } else {
-                            value = currentValue.copy(
-                                data1 = AsyncData.Success(step.data),
-                                dataToRender = 1,
-                            )
-                        }
+                        value = ShowQrCodeState(
+                            data = AsyncData.Success(step.data),
+                        )
                     }
                     is LinkMobileStep.QrRotating -> {
                         if (qrCodeRotationCounter-- > 0) {
@@ -75,17 +64,9 @@ class ShowQrCodePresenter(
                             // Ensure that outdated data is not rendered too long while rotating QR code
                             loadingJob = launch {
                                 delay(1000)
-                                if (currentValue.dataToRender == 1) {
-                                    value = currentValue.copy(
-                                        data2 = AsyncData.Loading(),
-                                        dataToRender = 2,
-                                    )
-                                } else {
-                                    value = currentValue.copy(
-                                        data1 = AsyncData.Loading(),
-                                        dataToRender = 1,
-                                    )
-                                }
+                                value = ShowQrCodeState(
+                                    data = AsyncData.Loading(),
+                                )
                             }
                         } else {
                             Timber.tag(tag.value).w("Max QR code rotation reached, not rotating anymore")

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodeState.kt

@@ -10,7 +10,5 @@ package io.element.android.features.linknewdevice.impl.screens.qrcode
 import io.element.android.libraries.architecture.AsyncData
 
 data class ShowQrCodeState(
-    val data1: AsyncData<String>,
-    val data2: AsyncData<String>,
-    val dataToRender: Int,
+    val data: AsyncData<String>,
 )

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodeStateProvider.kt

@@ -15,22 +15,13 @@ class ShowQrCodeStateProvider : PreviewParameterProvider<ShowQrCodeState> {
         get() = sequenceOf(
             aShowQrCodeState(),
             aShowQrCodeState(
-                data1 = AsyncData.Loading(),
-            ),
-            aShowQrCodeState(
-                data1 = AsyncData.Success("DATA"),
-                data2 = AsyncData.Success("DATA2"),
-                dataToRender = 2,
+                data = AsyncData.Loading(),
             ),
         )
 }
 
 internal fun aShowQrCodeState(
-    data1: AsyncData<String> = AsyncData.Success("DATA"),
-    data2: AsyncData<String> = AsyncData.Uninitialized,
-    dataToRender: Int = 1,
+    data: AsyncData<String> = AsyncData.Success("DATA"),
 ) = ShowQrCodeState(
-    data1 = data1,
-    data2 = data2,
-    dataToRender = dataToRender,
+    data = data,
 )

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodeView.kt

@@ -9,9 +9,11 @@
 
 package io.element.android.features.linknewdevice.impl.screens.qrcode
 
-import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.AnimatedContent
+import androidx.compose.animation.ExperimentalAnimationApi
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
+import androidx.compose.animation.togetherWith
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Spacer
@@ -44,6 +46,7 @@ import kotlinx.collections.immutable.persistentListOf
  * QrCode display screen:
  * https://www.figma.com/design/pDlJZGBsri47FNTXMnEdXB/Compound-Android-Templates?node-id=2027-23617
  */
+@OptIn(ExperimentalAnimationApi::class)
 @Composable
 fun ShowQrCodeView(
     state: ShowQrCodeState,
@@ -61,14 +64,15 @@ fun ShowQrCodeView(
             Modifier.fillMaxWidth(),
             horizontalAlignment = Alignment.CenterHorizontally,
         ) {
-            Box {
+            AnimatedContent(
+                targetState = state.data.dataOrNull(),
+                transitionSpec = {
+                    fadeIn().togetherWith(fadeOut())
+                }
+            ) { data ->
                 QrCodeOrLoading(
-                    isVisible = state.dataToRender == 1,
-                    data = state.data1.dataOrNull(),
-                )
-                QrCodeOrLoading(
-                    isVisible = state.dataToRender == 2,
-                    data = state.data2.dataOrNull(),
+                    modifier = modifier.size(220.dp),
+                    data = data,
                 )
             }
             Spacer(modifier = Modifier.height(32.dp))
@@ -92,31 +96,21 @@ fun ShowQrCodeView(
 
 @Composable
 private fun QrCodeOrLoading(
-    isVisible: Boolean,
     data: String?,
     modifier: Modifier = Modifier,
 ) {
-    AnimatedVisibility(
-        modifier = modifier,
-        visible = isVisible,
-        enter = fadeIn(),
-        exit = fadeOut(),
-    ) {
-        if (data == null) {
-            Box(
-                modifier = Modifier
-                    .size(220.dp),
-                contentAlignment = Alignment.Center,
-            ) {
-                CircularProgressIndicator()
-            }
-        } else {
-            QrCodeImage(
-                data = data,
-                modifier = Modifier
-                    .size(220.dp)
-            )
+    if (data == null) {
+        Box(
+            modifier = modifier,
+            contentAlignment = Alignment.Center,
+        ) {
+            CircularProgressIndicator()
         }
+    } else {
+        QrCodeImage(
+            modifier = modifier,
+            data = data,
+        )
     }
 }
 

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodePresenterTest.kt

@@ -32,9 +32,7 @@ class ShowQrCodePresenterTest {
     fun `present - initial state`() = runTest {
         createPresenter().test {
             val initialState = awaitItem()
-            assertThat(initialState.data1.dataOrNull()).isEqualTo("DATA")
-            assertThat(initialState.data2.isUninitialized()).isTrue()
-            assertThat(initialState.dataToRender).isEqualTo(1)
+            assertThat(initialState.data.dataOrNull()).isEqualTo("DATA")
         }
     }
 
@@ -61,8 +59,7 @@ class ShowQrCodePresenterTest {
             )
             runCurrent()
             val finalState = awaitItem()
-            assertThat(finalState.data2.isLoading()).isTrue()
-            assertThat(finalState.dataToRender).isEqualTo(2)
+            assertThat(finalState.data.isLoading()).isTrue()
             createLinkMobileHandlerResult.assertions().isCalledExactly(2)
         }
     }
@@ -90,9 +87,7 @@ class ShowQrCodePresenterTest {
                 LinkMobileStep.QrReady("DATA2")
             )
             val finalState = awaitItem()
-            assertThat(finalState.data1.dataOrNull()).isEqualTo("DATA")
-            assertThat(finalState.data2.dataOrNull()).isEqualTo("DATA2")
-            assertThat(finalState.dataToRender).isEqualTo(2)
+            assertThat(finalState.data.dataOrNull()).isEqualTo("DATA2")
         }
     }