AsyncStorage获取项

Question

如何在“AsyncStorage”中获取componentDidMount项，这是我的代码

​

componentDidMount() {

	AsyncStorage.getItem('customer_id').then((value)=> this.setState({ customer_id: value }));
        console.log(this.state.customer_id); /* doesn't work */
        console.log(`${this.state.customer_id}`); /* doesn't work */
  }
	
	
  render() {return <View><Text>Customer ID : {this.state.customer_id}</Text></View>; /* it's work */     }

​

Answer 1

你必须处理AsyncStorage -异步的，有趣的！无论如何，您希望将一个回调传递给处理结果的getItem方法。试一试

componentDidMount(){
    AsyncStorage.getItem('customer_id', (error,value) => {
        if (!error) { //If there are no errors
            //handle result
            if (result !== null) this.setState({customer_id:value}); 
        }
    });
}

Answer 2

try {
   const value = await AsyncStorage.getItem('@MySuperStore:key');
     if (value !== null){
    // We have data!!
    console.log(value);
  }
} catch (error) {
  // Error retrieving data
}

要了解更多信息，您可以访问官方文档。

Answer 3

这是我的答案，来自赖安的回答。

​

var cust_id_tmp = '';

AsyncStorage.getItem('customer_id', function(errs, result) {
  if (!errs) {
    if (result !== null) {
      //this.setState({customer_id:result}); <= we can't do this
      cust_id_tmp = result;
      console.log('customer_id : ' + result); /* it works */

    }
  }
}).then((value) => this.setState({
  cust_id: cust_id_tmp
}));

​