JSON 解析错误:意外的标识符“未定义"(React Native)

问题描述

我正在尝试使用异步存储来存储两个作为对象存储的文本输入值，并将其传递到不同的视图，在那里它们将在按下按钮时显示.

I'm trying to use Async storage to store two Text Input values stored as an object and pass it to a different view where they'll be displayed on a button press.

正如其他 StackOverflow 帖子中提到的，我使用 JSON.parse 和 JSON.stringify 将对象作为 JSON 数据传递，但仍然出于某种原因，我收到错误 JSON Parse Error: Unexpected Identifier "Undefined"(React Native)

As mentioned in other StackOverflow posts I've used JSON.parse and JSON.stringify to pass the object as JSON data, still for some reason I;m getting the error JSON Parse Error: Unexpected Identifier "Undefined"(React Native)

class AddData extends React.Component {
    constructor(props) {
    super(props);
    this.state = {
        text1: '' ,
        text2: ''

    };
}
  render() {
      function BtnPress() {
          alert('Hi')
      }
    return (
      <View style={{flex: 1, flexDirection: 'column', justifyContent:'center', alignItems: 'center'}}>
          <TextInput
          style={{height: 40,width:200}}
          onChangeText={(text1) => this.setState({input1: text1})}
            />
          <TextInput
          style={{height: 40,width:200}}
          onChangeText={(text2) => this.setState({input2: text2})}
            />
            <Button
            onPress={() => {
                AsyncStorage.setItem('user', JSON.stringify({
                    name:'Rohit',
                    email: 'rohitgird12gmail.com'
                }));
                this.props.navigation.navigate('Home', {});
            }}
            title="Submit"
/>


      </View>


    );
  }
}

查看以显示数据

class DetailsScreen extends React.Component {

         displayName = async ()=> {
            try {
              const myArray = await AsyncStorage.getItem('user');
              if (myArray !== null) {
                alert(JSON.parse(myArray.name));
              }
            } catch (error) {
                alert(error)
            }
        }
  render() {

    return (
      <View style={{flex: 1, flexDirection: 'column', justifyContent:'center', alignItems: 'center'}}>
      <Button
      onPress={this.displayName}
      title="Get Data"
/>

      </View>
    );
  }
}

推荐答案

看起来 const myArray = await AsyncStorage.getItem('user'); 正在返回 undefined而你只为 null 辩护，这在这里是不够的.

It looks like const myArray = await AsyncStorage.getItem('user'); is returning undefined while you defended yourself from null only, which is not sufficient here.

另一个可能的问题是:JSON.parse(myArray.name).你确定它不应该是 JSON.parse(myArray).name?

Antoher possible problem lies here : JSON.parse(myArray.name). Are you sure it's not supposed to be JSON.parse(myArray).name?

这篇关于JSON 解析错误:意外的标识符“未定义"(React Native)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！