我从手册中复制粘贴了一个 Picker
示例,但我不断收到以下错误:
TypeError:TypeError:TypeError:无法读取undefined的属性'value'此错误位于:在PickerAndroid中(在Picker.js:158处)在Picker中(在NewNotification.js:32处)在RCTView中(在View.js:60) )在RCViewiew中的SceneView(在StackViewLayout.js:478)的NewNotification(在SceneView.js:9)的KeyboardAvoidingView(在NewNotification.js:23)中的View(在KeyboardAvoidingView.js:196中)(在View.js:60) )在视图中的RCTView(在View.js:60)中的视图(在StackViewLayout.js:477中)在视图中的RCTView(在View.js:60)中的视图中(在createAnimatedComponent.js:154处) )在Screen中的AnimatedComponent(at screens.js:51)中的Screen(at StackViewCard.js:42)中的Card(at CreatePointerEventsContainer.js:26)在RCTView中的Container(at StackViewLayout.js:507)中(在View.js:60) )在StackViewLayout中的View(在StackViewLayout.js:400)的RCTView(在View.js:60)中的ScreenContainer(在StackViewLayout.js:401)中的View(at screens.js:76)中(atOrientation.js:30) )在RCTView中的withOrientation(在StackView.js:49)(at View.js:60)在视图中(在Transitioner.js:141)在Transitioner中(在StackView.js:19)在StackView中(在createNavigator.js:57)在Navigator中(在createKeyboardAwareNavigator.js:11)在KeyboardAwareNavigator中(在createNavigationContainer.js:376)在NavigationContainer(在App.js:23)中的应用程序(在registerRootComponent.js:35)中的RootErrorBoundary(在registerRootComponent.js:34)在ExpoRootComponent(at renderApplication.js:33)中的RCTView(at View.js:60)在AppContainer中的View(at AppContainer.js:122)的RCTView(在View.js:60)中的View(at AppContainer.js:102)中(在renderApplication.js:32)
我的代码看起来像这样:
state = {
location: 'a'
}
render(){
return(
<Picker
selectedValue={this.state.location}
style={styles.picker}>
onValueChange={(itemValue, itemIndex) => this.setState({location: itemValue})}>
<Picker.Item label="a" value="a" />
<Picker.Item label="b" value="b" />
<Picker.Item label="c" value="c" />
<Picker.Item label="d" value="d" />
</Picker>
)}
更多信息:
"expo": "^30.0.1",
"react": "16.3.1",
"react-native": "https://github.com/expo/react-native/archive/sdk-30.0.0.tar.gz",
"react-navigation": "^2.18.1"
1 回答
您的代码中有一个错字
它应该是