无法将道具从父组件传递给子组件
无法将道具从父组件传递给子组件
提问于 2019-08-20 20:48:54
我的App.js中有导航屏幕，其中一个屏幕将自定义标题呈现为：
const DailyStack = createStackNavigator({
Dashboard,
SalesDashboard: {
screen : SalesDashboard,
navigationOptions:{
header: null,
}
},
StackNavSecond : {
screen: StackNavSecond,
navigationOptions : {
header : <CustomHeader />,
}
},....然后在我的CustomHeader.js文件中，我有一些状态数据：
class CustomHeader extends Component {
constructor(props) {
super(props)
this.state = {
title:'Regions',
subtitle:'',
oem: ''
}
}
async componentDidMount(){
let car_brand = await AsyncStorage.getItem('brand_name');
let main_oem = await AsyncStorage.getItem('oem_name');
await this.setState({
oem: main_oem,
subtitle: car_brand,
});
console.log(this.state.oem)
}
render() {
console.log(this.state.title)
const {title, subtitle, oem} = this.state;
return (
<View>
<CustomDropdown title={title} subtitle={subtitle} oem={oem} />
</View>
)
}
}
export default withNavigation(CustomHeader);prop title不会被传递给它的子组件，它将在另外两个屏幕中进一步呈现。
CustomDropdown.js的代码是：
class CustomDropdown extends Component {
constructor(props) {
super(props)
this.state = {
title: '',
oem: '',
subtitle:''
};
}
componentDidMount(){
this.setState({
title:this.props.title,
subtitle: this.props.subtitle,
oem: this.props.oem,
});
console.log(this.state.title, this.state.oem, this.state.subtitle)
}
render() {
return (
<View style={{flexDirection:'row', justifyContent: 'space-between'}}>
.........
</View>
)
}
}
export default withNavigation(CustomDropdown);当我对this.state.title进行控制台操作时，它打印出subtitle和oem的值。
请帮助解决此问题。
回答 1
Stack Overflow用户
发布于 2019-08-20 21:16:27
当您不想交付组件时，可以使用withNavigation。但是你的代码嵌套得很深。
如果你想像这样使用它，你可以像这样修改代码。
CustomHeader.js
class CustomHeader extends React.Component {
constructor(props) {
super(props)
this.state = {
title:'Regions',
subtitle:'',
oem: ''
}
}
async componentDidMount(){
let car_brand = await AsyncStorage.getItem('brand_name');
let main_oem = await AsyncStorage.getItem('oem_name');
this.setState({
oem: main_oem,
subtitle: car_brand,
});
console.log(this.state.oem)
}
render() {
console.log(this.state.title)
const {title, subtitle, oem} = this.state;
return (
<View>
<CustomDropdown title={title} subtitle={subtitle} oem={oem} />
</View>
)
}
}
export default withNavigation(CustomHeader);CustomDropdown.js
class CustomDropdown extends React.Component {
constructor(props) {
super(props);
this.state = {
title: props.title,
oem: props.oem,
subtitle: props.subtitle
};
}
componentDidMount(){
console.log(this.state.title, this.state.oem, this.state.subtitle)
}
render() {
return (
<View style={{flexDirection:'row', justifyContent: 'space-between'}}>
.........
</View>
)
}
}
export default CustomDropdown;页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/57574076
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