无法在React本机中使用AsyncStorage存储和检索数据

Question

我是新来对本机做出反应的，我只是在学习反应原生现在，我试图通过单击注册按钮来存储TextInput中的值并将其存储到AsyncStorage中。该值通过单击获取Button.I无法从AsyncStorage.getItem（'值'）获得值，后来我认为其他数据存储在AsyncStorage.setItem（'name'，'value'）。有人看这段代码并告诉我我的错误答案。

export default class AsyncStorageEample extends Component 
{ 

constructor(props) 
{ 
super(props) 

    this.state= { name:'', email:'',mobile:''} 
    this.onRegisterPress=this.onRegisterPress.bind(this) 
    this.onRetreive=this.onRetreive.bind(this) 

} 

onRegisterPress() 
{ 
    let name=this.state.name 
    let email=this.state.email 
    let mobile=this.state.mobile 

    AsyncStorage.setItem('name',name) 
    AsyncStorage.setItem('email',email) 
    AsyncStorage.setItem('mobile',mobile) 

    this.setState({name: name, email:email,mobile:mobile}) 


} 

onRetreive() 
{ 
    var user; 
    user= AsyncStorage.getItem('name').then((value) => this.setState({ 'name': value })) 

    Alert.alert('Name:'+user); 
} 

render() { 
    return (
     <View style={styles.container}> 
     <View style={styles.Signupform}> 

     <Text style={styles.textStyle}> Name </Text> 
     <TextInput style={styles.tInRegister} onChangeText={(text)=> this.setState({name: text})} value = {this.state.name}/> 

     <Text style={styles.textStyle}> Email </Text> 
     <TextInput style={styles.tInRegister} onChangeText={(text)=> this.setState({email: text})} value= {this.state.email} /> 

     <Text style={styles.textStyle}> Mobile </Text> 
     <TextInput style={styles.tInRegister} onChangeText={(text)=> this.setState({mobile: text})} vaue= {this.state.mobile} /> 

     <Button 
     onPress={this.onRegisterPress.bind(this)} 
     title="Register" 
     color="#841584" 
     /> 

     <Button 
     style={styles.get} 
     onPress={this.onRetreive.bind(this)} 
     title="Get" 
     color="#841584"/> 
     </View> 
     </View> 
    ); 
} 
} 

    const styles = StyleSheet.create({ 
     container: { 
      flex: 1, 
      justifyContent: 'center', 
      alignItems: 'center', 

      backgroundColor: '#F5FCFF', 
     }, 

     tInRegister: { 
      fontSize: 16, 
      height: 40, 
      color: '#800080' 
     }, 
     textStyle: { 
      fontSize: 16, 
      color: '#800080' 
     }, 
     Signupform: { 
      width: 400, 
      height: 100, 
      justifyContent: 'center', 
      marginTop: 10, 
      marginLeft: 10, 
      marginRight: 10 

     }, 
     get: 
     { 
      marginTop:20, 
     }, 


}); 

     AppRegistry.registerComponent('AsyncStorageEample',() =>  AsyncStorageEample); 

Answer 1

AsyncStorage是一个异步操作。所以应该用'异步 - 等待'来完成。

尝试下面的代码即使在[文档】（https://facebook.github.io/react-native/docs/asyncstorage.html） '异步-AWAIT'

async onRetreive() { 
    const user = await AsyncStorage.getItem('name'); 
    Alert.alert('Name:'+user); 
}