React-Native

Question

昨天开始学习React Native。不幸的是，我一开始就遇到了一些困难。我试图编写简单的列表，其中包含一些输入，当用户单击 "Add new" 按钮时，列表将扩展为新项目。当我尝试在新列表元素中使用 this.state.newName 变量时，React 抛出异常：

" Invariant Violation: Objects are not valid as a React child (found: object with keys {dispatchConfig, _targetInst, isDefaultPrevented, isPropagationStopped, _dispatchListeners, _dispatchInstances, type, target, currentTarget, eventPhase, bubbles, cancelable, timeStamp, defaultPrevented, isTrusted, nativeEvent}). If you meant to render a collection of children, use an array instead."

我的代码真的很简单：

export default class HelloWorldApp extends Component {

constructor() {
    super();
    this.state = {
        newName: "",
        peopleList: [
            { key: "1", name: "Jonathan", lastname: "Smith" },
            { key: "2", name: "Tomasz", lastname: "Kowalski" },
            { key: "2", name: "Adrian", lastname: "Jakubowski" },
        ]

    }
}

addNew() {
    let newName = this.state.newName;
    this.setState({
         peopleList: [...this.state.peopleList, {key: newName, name: newName, lastname: "Added"}]
    });
}

render() {
    return (
        <View style={styles.peopleList}>
            <Text>People I know:</Text>
            <TextInput
                value={this.state.newName}
                onChange={(text) => this.setState({newName: text})}
            />
            <Button title="Add new!" 
                onPress={() => this.addNew()}
            />
            <FlatList
                data={this.state.peopleList}
                renderItem={({ item }) => <Text style={styles.item}>Imie: {item.name} Nazwisko: {item.lastname}</Text>} />

        </View>
    );
}

}

当我不使用 this.state.newName 时，只需传递一些字符串，如：

let newName = "Adam";

它会工作得很好。可能是什么原因？

Answer 1

改变这个：

onChange={(text) => this.setState({newName: text})}

收件人：

onChangeText={(text) => this.setState({newName: text})}

正确的道具是onChangeText

具体用法见here

React-Native - 我不能使用状态字符串作为新的列表元素

React-Native - I can not use State string as new list element

javascript

reactjs

native

expo