React Native：调用try-catch函数时setState不起作用

Question

I tried to call APP with this code imported from another file and it worked fine:

import FormData from 'FormData';
import AsyncStorage from '@react-native-community/async-storage';

let formData = new FormData();

formData.append('userId', '1'); // < this is what I want to change
formData.append('key', '***'); //my key

 export function getScoreFromAPI () {
   return fetch('https://www.globalfidelio.com/gfn_arcol/api/transaction.php',{
                 method : 'POST',
                 headers : {
                   'Accept': 'application/json',
                   'Content-Type': 'multipart/form-data'
                 },
                 body : formData
             } )
       .then((response) => {
          return response.json()
       })
    .catch((error) => console.log("l'erreure est:  " + error))
 }

but now I want to change my userId from 1 to an constante from Asyncstorage, so I decide to change my code to this:

  constructor(props) {
      super(props)
      this.state = { infos: [], userId: '' }
  }

  componentWillMount() {
    this.getScoreFromAPI().then(data => {
      this.setState({ infos: data })
    });
    console.log(this.state.infos);
    AsyncStorage.getItem(USERID_STORED)
    .then((data) => {
        if (data) {
           this.setState({userId:data})
        }
    });
  }
  async getScoreFromAPI() {
      let formData = new FormData();
      formData.append('userId', this.state.userId);
      formData.append('key', '***'); //my key
    try {
      let response = await fetch('https://www.globalfidelio.com/gfn_arcol/api/transaction.php',{
        method: 'POST',
        headers: {
          'Accept': 'application/json',
          'Content-Type': 'multipart/form-data'
        },
        body: formData
      })
      let res = await response.json();

  } catch(error) {
      console.warn("errors are " + error);
  }
};

with a try-catch function but when I call getScoreFromAPI() in ComponentWillMount() I can't setState with received data, I still have an empty array in info:[]

my questions:

how can I replace '1' in userId by a value in asyncstorage in the first file ?

if it isn't possible, what I have do to setState info: [] with my data reveived

Answer 1

1. You're doing your API call before fetching your value from AsyncStorage (I know this is async but it's not very readable if you do it that way).
2. getScoreFromAPI doesn't return anything, that's why your setState isn't working.
3. You don't need to use try and catch here, promises have their own error handling mechanism (the .catch() method).
4. I think callbacks are more readable and lead to less bugs than using .then() in code.

This is how I would do it:

constructor(props)
{
    super(props);
    this.state = { infos: [], userId: '' };
    this.onSuccess = this.onSuccess.bind(this);
    this.onFailure = this.onFailure.bind(this);
}

componentWillMount()
{
    // Get userID from local storage, then call your API 
    AsyncStorage.getItem(YOUR_KEY)
        .then(userID=> {
            if (userID)
            {
                this.setState({ userId : userID }, () => {
                    this.getScoreFromAPI(this.onSuccess, this.onFailure); 
                });
            }
        });
}

onSuccess(data)
{
    this.setState({
        infos : data
    });
}

onFailure(err)
{
    console.warn('Error ' + err);
}

getScoreFromAPI(onSuccess, onFailure)
{
    let formData = new FormData();
    formData.append('userId', this.state.userId);
    formData.append('key', '***'); //your key

    fetch('https://www.globalfidelio.com/gfn_arcol/api/transaction.php', {
        method : 'POST',
        headers: {
          'Accept': 'application/json',
          'Content-Type': 'multipart/form-data'
        },
        body: formData
    })
    .then(res => res.json())
    .then(json => {
        onSuccess(json);
    })
    .catch(err => {
        onFailure(err);
    });
} 

Answer 2

I've simplified your code into a promise chain in which calling getScoreFromAPI will execute after getting the userId from AsyncStorage, then storing the response into the infos state, while returning null if there was an error, and logging the error to the console. The data was not previously returned from getScoreFromAPI , so the value would always become null . I have not tested this code, but this should give you a good base to work from:

import FormData from 'FormData';
import AsyncStorage from '@react-native-community/async-storage';

export default class Test {
    constructor() {
        this.state = {
            infos: null,
            userId: ''
        };
    }

    componentDidMount() {
        AsyncStorage.getItem(this.state.userId)
            .then(userID => {
                this.setState({ userId: userID || '' });
            })
            .then(() => {
                return this.getScoreFromAPI();
            })
            .then(data => {
                this.setState({ infos: data });
            })
            .catch(console.error);
    }

    getScoreFromAPI = () => {
        const formData = new FormData();

        formData.append('userId', this.state.userId);
        formData.append('key', '***'); //my key

        fetch('https://www.globalfidelio.com/gfn_arcol/api/transaction.php', {
            method: 'POST',
            headers: {
                Accept: 'application/json',
                'Content-Type': 'multipart/form-data'
            },
            body: formData
        })
            .then(response => {
                // use response data here
                return response.json();
            })
            .catch(e => {
                console.error(e);
                return null;
            });
    };
}

Answer 3

It's finally done. I tried this and it worked. Thank you to all of you

this is what I have done:

...
const USERID_STORED = "userid_stored";
const GSM_STORED = "gsm_stored";
...
class ScoreList extends React.Component {
  constructor(props) {
      super(props)
      this.state = { infos: [], userId: '', gsmStored: '', }
  }

  componentWillMount() {
    AsyncStorage.getItem(USERID_STORED)
        .then(userId => {
                this.setState({ userId: userId});
                this.getScoreFromAPI(this.state.userId).then(data => {
                  this.setState({ infos: data });
                });
        });
    AsyncStorage.getItem(GSM_STORED)
        .then(gsmStore => {
                this.setState({ gsmStored: gsmStore});
        });
  }

  getScoreFromAPI (userId) {
    let formData = new FormData();
    formData.append('userId', userId);
    formData.append('key', '***');
    return fetch('https://***',{
                   method : 'POST',
                   headers : {
                     'Accept': 'application/json',
                     'Content-Type': 'multipart/form-data'
                   },
                   body : formData
               } )
         .then((response) => {
            return response.json()
         })
      .catch((error) => console.log("l'erreure est:  " + error))
   };