CODEWITHSUNDEEP
androidandroid-jetpackandroid-jetpack-compose
Khantahr
Khantahr

Reputation: 8528

Is there a way to preview a compose function with a StateFlow parameter?

Here is my function header:

@Composable
@OptIn(ExperimentalMaterialApi::class)
@Preview(showBackground = true)
fun ListPreference(
    title: String = "Title",
    currentValue: StateFlow<String> = MutableStateFlow("C"),
    @PreviewParameter(PreviewTypesProvider::class) types: List<ListPreference>,
    onSelected: ((String) -> Unit)? = null
) {
    val secondaryText by currentValue.collectAsState()

When it tries to render the preview, I get an error. If I remove the currentValue parameter (and comment out its usage), it renders successfully. Is there a way to get the the preview to work with a StateFlow parameter?

java.lang.IllegalArgumentException: argument type mismatch at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at androidx.compose.ui.tooling.CommonPreviewUtils.invokeComposableMethod(CommonPreviewUtils.kt:149) at androidx.compose.ui.tooling.CommonPreviewUtils.invokeComposableViaReflection$ui_tooling_release(CommonPreviewUtils.kt:188) at androidx.compose.ui.tooling.ComposeViewAdapter$init$3$1$composable$1.invoke(ComposeViewAdapter.kt:571) at androidx.compose.ui.tooling.ComposeViewAdapter$init$3$1$composable$1.invoke(ComposeViewAdapter.kt:569) at androidx.compose.ui.tooling.ComposeViewAdapter$init$3$1.invoke(ComposeViewAdapter.kt:608) at androidx.compose.ui.tooling.ComposeViewAdapter$init$3$1.invoke(ComposeViewAdapter.kt:564) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34) at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:215) at androidx.compose.ui.tooling.InspectableKt.Inspectable(Inspectable.kt:64) at androidx.compose.ui.tooling.ComposeViewAdapter$WrapPreview$1.invoke(ComposeViewAdapter.kt:513) at androidx.compose.ui.tooling.ComposeViewAdapter$WrapPreview$1.invoke(ComposeViewAdapter.kt:512) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34) at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:215) at androidx.compose.ui.tooling.ComposeViewAdapter.WrapPreview(ComposeViewAdapter.kt:508) at androidx.compose.ui.tooling.ComposeViewAdapter.access$WrapPreview(ComposeViewAdapter.kt:121) at androidx.compose.ui.tooling.ComposeViewAdapter$init$3.invoke(ComposeViewAdapter.kt:564) at androidx.compose.ui.tooling.ComposeViewAdapter$init$3.invoke(ComposeViewAdapter.kt:561) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34) at androidx.compose.ui.platform.ComposeView.Content(ComposeView.android.kt:384) at androidx.compose.ui.platform.AbstractComposeView$ensureCompositionCreated$1.invoke(ComposeView.android.kt:228) at androidx.compose.ui.platform.AbstractComposeView$ensureCompositionCreated$1.invoke(ComposeView.android.kt:227) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34) at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:215) at androidx.compose.ui.platform.CompositionLocalsKt.ProvideCommonCompositionLocals(CompositionLocals.kt:148) at androidx.compose.ui.platform.AndroidCompositionLocals_androidKt$ProvideAndroidCompositionLocals$3.invoke(AndroidCompositionLocals.android.kt:114) at androidx.compose.ui.platform.AndroidCompositionLocals_androidKt$ProvideAndroidCompositionLocals$3.invoke(AndroidCompositionLocals.android.kt:113) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34) at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:215) at androidx.compose.ui.platform.AndroidCompositionLocals_androidKt.ProvideAndroidCompositionLocals(AndroidCompositionLocals.android.kt:106) at androidx.compose.ui.platform.WrappedComposition$setContent$1$1$3.invoke(Wrapper.android.kt:162) at androidx.compose.ui.platform.WrappedComposition$setContent$1$1$3.invoke(Wrapper.android.kt:161) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34) at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:215) at androidx.compose.ui.platform.WrappedComposition$setContent$1$1.invoke(Wrapper.android.kt:161) at androidx.compose.ui.platform.WrappedComposition$setContent$1$1.invoke(Wrapper.android.kt:144) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107) at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34) at androidx.compose.runtime.ComposerKt.invokeComposable(Composer.kt:3330) at androidx.compose.runtime.ComposerImpl$doCompose$2$5.invoke(Composer.kt:2577) at androidx.compose.runtime.ComposerImpl$doCompose$2$5.invoke(Composer.kt:2573) at androidx.compose.runtime.SnapshotStateKt.observeDerivedStateRecalculations(SnapshotState.kt:540) at androidx.compose.runtime.ComposerImpl.doCompose(Composer.kt:2566) at androidx.compose.runtime.ComposerImpl.composeContent$runtime_release(Composer.kt:2517) at androidx.compose.runtime.CompositionImpl.composeContent(Composition.kt:476) at androidx.compose.runtime.Recomposer.composeInitial$runtime_release(Recomposer.kt:727) at androidx.compose.runtime.CompositionImpl.setContent(Composition.kt:432) at androidx.compose.ui.platform.WrappedComposition$setContent$1.invoke(Wrapper.android.kt:144) at androidx.compose.ui.platform.WrappedComposition$setContent$1.invoke(Wrapper.android.kt:135) at androidx.compose.ui.platform.AndroidComposeView.setOnViewTreeOwnersAvailable(AndroidComposeView.android.kt:727) at androidx.compose.ui.platform.WrappedComposition.setContent(Wrapper.android.kt:135) at androidx.compose.ui.platform.WrappedComposition.onStateChanged(Wrapper.android.kt:187) at androidx.lifecycle.LifecycleRegistry$ObserverWithState.dispatchEvent(LifecycleRegistry.java:354) at androidx.lifecycle.LifecycleRegistry.addObserver(LifecycleRegistry.java:196) at androidx.compose.ui.platform.WrappedComposition$setContent$1.invoke(Wrapper.android.kt:142) at androidx.compose.ui.platform.WrappedComposition$setContent$1.invoke(Wrapper.android.kt:135) at androidx.compose.ui.platform.AndroidComposeView.onAttachedToWindow(AndroidComposeView.android.kt:814) at android.view.View.dispatchAttachedToWindow(View.java:20479) at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3489) at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3496) at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3496) at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3496) at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3496) at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3496) at android.view.AttachInfo_Accessor.setAttachInfo(AttachInfo_Accessor.java:44) at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:360) at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:431) at com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:141) at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:714) at com.android.tools.idea.rendering.RenderTask.lambda$inflate$7(RenderTask.java:870) at com.android.tools.idea.rendering.RenderExecutor$runAsyncActionWithTimeout$2.run(RenderExecutor.kt:187) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base/java.lang.Thread.run(Thread.java:834)

Upvotes: 1

Views: 1549

Answers (1)

Gabriele Mariotti
Gabriele Mariotti

Reputation: 364055

You can define a custom PreviewParameter implementing the interface PreviewParameterProvider.

Something like:

class SampleStateFlowProvider: PreviewParameterProvider<MutableStateFlow<String>> {
    override val values = sequenceOf(MutableStateFlow("A"),MutableStateFlow("D"))
    override val count: Int = values.count()
}

@Preview(showBackground = true)
@Composable
fun ListPreferencePreview(@PreviewParameter(SampleStateFlowProvider::class) stateFlow: MutableStateFlow<String>) {
    ListPreference("Title", stateFlow, {/*...*/})
}

@Composable
@OptIn(ExperimentalMaterialApi::class)
fun ListPreference(
    title: String = "Title",
    currentValue: StateFlow<String> = MutableStateFlow("C"),
    onSelected: ((String) -> Unit)? = null
) {
    val secondaryText by currentValue.collectAsState()

    //..Text(currentValue.value)
}

enter image description here

Upvotes: 2

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