Android studio Composable Preview Render 问题
Android studio Composable Preview Render problem
我在从文件预览可组合项时遇到这个问题。
这是我在其他 kotlin 文件中编写的代码。
package com.example.movieapp.screens.home.details
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxHeight
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.material.Surface
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import androidx.navigation.NavController
@Composable
@Preview(showSystemUi = true, showBackground = true)
fun DetailsScreen(navController: NavController, movieData: String?){
Surface(modifier = Modifier
.fillMaxWidth()
.fillMaxHeight()) {
Column(horizontalAlignment = Alignment.CenterHorizontally, verticalArrangement = Arrangement.Center) {
// Text(text = "Details here about $movieData")
Text(text = "Details here about")
}
}
}
预览设计时出现以下问题
java.lang.NullPointerException: Parameter specified as non-null is null: method com.example.movieapp.screens.home.details.DetailsScreenKt.DetailsScreen, parameter navController
at com.example.movieapp.screens.home.details.DetailsScreenKt.DetailsScreen(DetailsScreen.kt)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at androidx.compose.ui.tooling.CommonPreviewUtils.invokeComposableMethod(CommonPreviewUtils.kt:149)
at androidx.compose.ui.tooling.CommonPreviewUtils.invokeComposableViaReflection$ui_tooling_release(CommonPreviewUtils.kt:188)
at androidx.compose.ui.tooling.ComposeViewAdapter$init$composable.invoke(ComposeViewAdapter.kt:571)
at androidx.compose.ui.tooling.ComposeViewAdapter$init$composable.invoke(ComposeViewAdapter.kt:569)
at androidx.compose.ui.tooling.ComposeViewAdapter$init.invoke(ComposeViewAdapter.kt:608)
at androidx.compose.ui.tooling.ComposeViewAdapter$init.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:228)
at androidx.compose.ui.tooling.InspectableKt.Inspectable(Inspectable.kt:64)
at androidx.compose.ui.tooling.ComposeViewAdapter$WrapPreview.invoke(ComposeViewAdapter.kt:513)
at androidx.compose.ui.tooling.ComposeViewAdapter$WrapPreview.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:228)
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.invoke(ComposeViewAdapter.kt:564)
at androidx.compose.ui.tooling.ComposeViewAdapter$init.invoke(ComposeViewAdapter.kt:561)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.ui.platform.ComposeView.Content(ComposeView.android.kt:410)
at androidx.compose.ui.platform.AbstractComposeView$ensureCompositionCreated.invoke(ComposeView.android.kt:252)
at androidx.compose.ui.platform.AbstractComposeView$ensureCompositionCreated.invoke(ComposeView.android.kt:251)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:228)
at androidx.compose.ui.platform.CompositionLocalsKt.ProvideCommonCompositionLocals(CompositionLocals.kt:166)
at androidx.compose.ui.platform.AndroidCompositionLocals_androidKt$ProvideAndroidCompositionLocals.invoke(AndroidCompositionLocals.android.kt:123)
at androidx.compose.ui.platform.AndroidCompositionLocals_androidKt$ProvideAndroidCompositionLocals.invoke(AndroidCompositionLocals.android.kt:122)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:228)
at androidx.compose.ui.platform.AndroidCompositionLocals_androidKt.ProvideAndroidCompositionLocals(AndroidCompositionLocals.android.kt:114)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:157)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:156)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:228)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:156)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:140)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.runtime.ComposerKt.invokeComposable(Composer.kt:3337)
at androidx.compose.runtime.ComposerImpl$doCompose.invoke(Composer.kt:2582)
at androidx.compose.runtime.ComposerImpl$doCompose.invoke(Composer.kt:2571)
at androidx.compose.runtime.SnapshotStateKt__DerivedStateKt.observeDerivedStateRecalculations(DerivedState.kt:247)
at androidx.compose.runtime.SnapshotStateKt.observeDerivedStateRecalculations(Unknown Source)
at androidx.compose.runtime.ComposerImpl.doCompose(Composer.kt:2571)
at androidx.compose.runtime.ComposerImpl.composeContent$runtime_release(Composer.kt:2522)
at androidx.compose.runtime.CompositionImpl.composeContent(Composition.kt:478)
at androidx.compose.runtime.Recomposer.composeInitial$runtime_release(Recomposer.kt:748)
at androidx.compose.runtime.CompositionImpl.setContent(Composition.kt:433)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:140)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:131)
at androidx.compose.ui.platform.AndroidComposeView.setOnViewTreeOwnersAvailable(AndroidComposeView.android.kt:907)
at androidx.compose.ui.platform.WrappedComposition.setContent(Wrapper.android.kt:131)
at androidx.compose.ui.platform.WrappedComposition.onStateChanged(Wrapper.android.kt:182)
at androidx.lifecycle.LifecycleRegistry$ObserverWithState.dispatchEvent(LifecycleRegistry.java:354)
at androidx.lifecycle.LifecycleRegistry.addObserver(LifecycleRegistry.java:196)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:138)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:131)
at androidx.compose.ui.platform.AndroidComposeView.onAttachedToWindow(AndroidComposeView.android.kt:994)
at android.view.View.dispatchAttachedToWindow(View.java:20753)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3490)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.AttachInfo_Accessor.setAttachInfo(AttachInfo_Accessor.java:58)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:370)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:436)
at com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:121)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:739)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate(RenderTask.java:895)
at com.android.tools.idea.rendering.RenderExecutor$runAsyncActionWithTimeout.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:829)
但是在我的 MainActivity.kt 中，可组合预览没有错误。
图片如下：
main activity
DetailsScreen.kt 可组合问题：
DetailsScreen.kt
我所做的是：
我将依赖项从 $compose_version 更改为 1.1.1，因为 android 开发人员建议使用最新的稳定版本
build.Gradle 依赖关系：
dependencies {
implementation 'androidx.core:core-ktx:1.7.0'
implementation "androidx.compose.ui:ui:1.1.1"
implementation "androidx.compose.material:material:1.1.1"
implementation "androidx.compose.ui:ui-tooling-preview:1.1.1"
implementation "androidx.compose.ui:ui-tooling:1.0.1"
implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
implementation 'androidx.activity:activity-compose:1.3.1'
testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
androidTestImplementation "androidx.compose.ui:ui-test-junit4:1.1.1"
// debugImplementation "androidx.compose.ui:ui-tooling:$compose_version"
// debugImplementation "androidx.compose.ui:ui-test-manifest:$compose_version"
implementation "androidx.navigation:navigation-compose:2.4.2"
}
我找不到任何解决方案。
我的 android 工作室版本是：Android Studio Chipmunk 2021.2.1
我想知道为什么它只在 MainActivity 中有效并且只允许一个可组合预览。
有任何想法吗？谢谢
您需要将函数声明与其预览分开：
@Composable
fun DetailsScreen(navController: NavController, movieData: String?) {
//...
您可以根据需要进行任意数量的预览：
@Preview(showSystemUi = true, showBackground = true)
fun DetailsScreenPreview() { //no parameters here
DetailsScreen(navController = rememberNavController(), movieData = "Preview 1")
}
@Preview(showSystemUi = true, showBackground = true)
fun DetailsScreenPreview2() { //no parameters here
DetailsScreen(navController = rememberNavController(), movieData = "Preview 2")
}
我在从文件预览可组合项时遇到这个问题。
这是我在其他 kotlin 文件中编写的代码。
package com.example.movieapp.screens.home.details
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxHeight
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.material.Surface
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import androidx.navigation.NavController
@Composable
@Preview(showSystemUi = true, showBackground = true)
fun DetailsScreen(navController: NavController, movieData: String?){
Surface(modifier = Modifier
.fillMaxWidth()
.fillMaxHeight()) {
Column(horizontalAlignment = Alignment.CenterHorizontally, verticalArrangement = Arrangement.Center) {
// Text(text = "Details here about $movieData")
Text(text = "Details here about")
}
}
}
预览设计时出现以下问题
java.lang.NullPointerException: Parameter specified as non-null is null: method com.example.movieapp.screens.home.details.DetailsScreenKt.DetailsScreen, parameter navController
at com.example.movieapp.screens.home.details.DetailsScreenKt.DetailsScreen(DetailsScreen.kt)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at androidx.compose.ui.tooling.CommonPreviewUtils.invokeComposableMethod(CommonPreviewUtils.kt:149)
at androidx.compose.ui.tooling.CommonPreviewUtils.invokeComposableViaReflection$ui_tooling_release(CommonPreviewUtils.kt:188)
at androidx.compose.ui.tooling.ComposeViewAdapter$init$composable.invoke(ComposeViewAdapter.kt:571)
at androidx.compose.ui.tooling.ComposeViewAdapter$init$composable.invoke(ComposeViewAdapter.kt:569)
at androidx.compose.ui.tooling.ComposeViewAdapter$init.invoke(ComposeViewAdapter.kt:608)
at androidx.compose.ui.tooling.ComposeViewAdapter$init.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:228)
at androidx.compose.ui.tooling.InspectableKt.Inspectable(Inspectable.kt:64)
at androidx.compose.ui.tooling.ComposeViewAdapter$WrapPreview.invoke(ComposeViewAdapter.kt:513)
at androidx.compose.ui.tooling.ComposeViewAdapter$WrapPreview.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:228)
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.invoke(ComposeViewAdapter.kt:564)
at androidx.compose.ui.tooling.ComposeViewAdapter$init.invoke(ComposeViewAdapter.kt:561)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.ui.platform.ComposeView.Content(ComposeView.android.kt:410)
at androidx.compose.ui.platform.AbstractComposeView$ensureCompositionCreated.invoke(ComposeView.android.kt:252)
at androidx.compose.ui.platform.AbstractComposeView$ensureCompositionCreated.invoke(ComposeView.android.kt:251)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:228)
at androidx.compose.ui.platform.CompositionLocalsKt.ProvideCommonCompositionLocals(CompositionLocals.kt:166)
at androidx.compose.ui.platform.AndroidCompositionLocals_androidKt$ProvideAndroidCompositionLocals.invoke(AndroidCompositionLocals.android.kt:123)
at androidx.compose.ui.platform.AndroidCompositionLocals_androidKt$ProvideAndroidCompositionLocals.invoke(AndroidCompositionLocals.android.kt:122)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:228)
at androidx.compose.ui.platform.AndroidCompositionLocals_androidKt.ProvideAndroidCompositionLocals(AndroidCompositionLocals.android.kt:114)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:157)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:156)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.runtime.CompositionLocalKt.CompositionLocalProvider(CompositionLocal.kt:228)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:156)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:140)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:107)
at androidx.compose.runtime.internal.ComposableLambdaImpl.invoke(ComposableLambda.jvm.kt:34)
at androidx.compose.runtime.ComposerKt.invokeComposable(Composer.kt:3337)
at androidx.compose.runtime.ComposerImpl$doCompose.invoke(Composer.kt:2582)
at androidx.compose.runtime.ComposerImpl$doCompose.invoke(Composer.kt:2571)
at androidx.compose.runtime.SnapshotStateKt__DerivedStateKt.observeDerivedStateRecalculations(DerivedState.kt:247)
at androidx.compose.runtime.SnapshotStateKt.observeDerivedStateRecalculations(Unknown Source)
at androidx.compose.runtime.ComposerImpl.doCompose(Composer.kt:2571)
at androidx.compose.runtime.ComposerImpl.composeContent$runtime_release(Composer.kt:2522)
at androidx.compose.runtime.CompositionImpl.composeContent(Composition.kt:478)
at androidx.compose.runtime.Recomposer.composeInitial$runtime_release(Recomposer.kt:748)
at androidx.compose.runtime.CompositionImpl.setContent(Composition.kt:433)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:140)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:131)
at androidx.compose.ui.platform.AndroidComposeView.setOnViewTreeOwnersAvailable(AndroidComposeView.android.kt:907)
at androidx.compose.ui.platform.WrappedComposition.setContent(Wrapper.android.kt:131)
at androidx.compose.ui.platform.WrappedComposition.onStateChanged(Wrapper.android.kt:182)
at androidx.lifecycle.LifecycleRegistry$ObserverWithState.dispatchEvent(LifecycleRegistry.java:354)
at androidx.lifecycle.LifecycleRegistry.addObserver(LifecycleRegistry.java:196)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:138)
at androidx.compose.ui.platform.WrappedComposition$setContent.invoke(Wrapper.android.kt:131)
at androidx.compose.ui.platform.AndroidComposeView.onAttachedToWindow(AndroidComposeView.android.kt:994)
at android.view.View.dispatchAttachedToWindow(View.java:20753)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3490)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3497)
at android.view.AttachInfo_Accessor.setAttachInfo(AttachInfo_Accessor.java:58)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:370)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:436)
at com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:121)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:739)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate(RenderTask.java:895)
at com.android.tools.idea.rendering.RenderExecutor$runAsyncActionWithTimeout.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:829)
但是在我的 MainActivity.kt 中，可组合预览没有错误。 图片如下： main activity
DetailsScreen.kt 可组合问题： DetailsScreen.kt
我所做的是：
我将依赖项从 $compose_version 更改为 1.1.1，因为 android 开发人员建议使用最新的稳定版本
build.Gradle 依赖关系：
dependencies {
implementation 'androidx.core:core-ktx:1.7.0'
implementation "androidx.compose.ui:ui:1.1.1"
implementation "androidx.compose.material:material:1.1.1"
implementation "androidx.compose.ui:ui-tooling-preview:1.1.1"
implementation "androidx.compose.ui:ui-tooling:1.0.1"
implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
implementation 'androidx.activity:activity-compose:1.3.1'
testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
androidTestImplementation "androidx.compose.ui:ui-test-junit4:1.1.1"
// debugImplementation "androidx.compose.ui:ui-tooling:$compose_version"
// debugImplementation "androidx.compose.ui:ui-test-manifest:$compose_version"
implementation "androidx.navigation:navigation-compose:2.4.2"
}
我找不到任何解决方案。
我的 android 工作室版本是：Android Studio Chipmunk 2021.2.1
我想知道为什么它只在 MainActivity 中有效并且只允许一个可组合预览。 有任何想法吗？谢谢
您需要将函数声明与其预览分开：
@Composable
fun DetailsScreen(navController: NavController, movieData: String?) {
//...
您可以根据需要进行任意数量的预览：
@Preview(showSystemUi = true, showBackground = true)
fun DetailsScreenPreview() { //no parameters here
DetailsScreen(navController = rememberNavController(), movieData = "Preview 1")
}
@Preview(showSystemUi = true, showBackground = true)
fun DetailsScreenPreview2() { //no parameters here
DetailsScreen(navController = rememberNavController(), movieData = "Preview 2")
}