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[英]Updating Parent component state from Child component TextInput in React Native
[英]Updating child property from parent in React Native
我希望能夠根據上一個事件從父級和自身更新子級組件屬性。
例如:
class MyParent extends Component {
state ={
text:"";
}
render() {
return (
<View>
<MyChild text={this.state.text} />
<Button
onPress={()=>this.setState({text:"parent"})}
title="Update From Parent"
/>
</View>
);
}
}
class MyChild extends Component {
state ={
text:"";
}
componentWillReceiveProps(nextProps) {
if (nextProps.text!== this.state.text) {
this.setState({text:nextProps.text});
}
}
render() {
return (
<View>
{/* I want that the text field will be updated from the last event*/}
<Text>{this.state.text}</Text>
<Button
onPress={()=>this.setState({text:"child"})}
title="Update From Child"
/>
</View>
);
}
}
問題在於,每次調用setState時都會觸發componentWillReceiveProps,因此text屬性從父級而不是子級獲取值。
我如何獲得這個結果?
非常感謝Elad
通過parent
組件管理state
,並pass
將更新child
組件中parent
組件state
的功能
class MyParent extends Component {
constructor(props) {
super(props);
this.state = {
text: "",
updateParentState: (newState) => this.setState(newState)
}
}
render() {
let { text, updateParentState } = this.state;
return (
<View>
<MyChild data={{ text, updateParentState }} />
<Button
onPress={() => updateParentState({ text: "parent" })}
title="Update From Parent"
/>
</View>
);
}
}
class MyChild extends Component {
constructor(props) {
super(props);
this.state = {
text: props.data.text
}
}
componentWillReceiveProps(nextProps) {
if (nextProps.text !== this.state.text) {
this.setState({ text: nextProps.data.text });
}
}
render() {
let { updateParentState } = this.props.data;
return (
<View>
<Text>{this.state.text}</Text>
<Button
onPress={() => updateParentState({ text: "child" })}
title="Update From Child"
/>
</View>
);
}
}
你錯過了這個。 在setState子項中。 請檢查這是否不是問題。
<Button
onPress={()=>setState({text:"child"})}
title="Update From Child"
/>
應該
<Button
onPress={()=>this.setState({text:"child"})}
title="Update From Child"
/>
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