How to properly fetch data from async storage in react native?

Question

I am attempting to load and retrieve local data through asynchronous storage. I've laid out the current set up on a page, but am unable to retrieve data. Data is definitely saved as I receive a notification about it once I click store data. But when I proceed to call data it returns a null value. What am I doing something wrong here?

const STORAGE_KEY = '@save_enableauto'

    state={
        enableAuto:false
    }

    _storeData = async enableAuto => {
        try {
          let x = toString(enableAuto);
          await AsyncStorage.setItem(STORAGE_KEY, x)
          alert('Data successfully saved!')
          //this.setState({ enableAuto: x })
        } catch (e) {
            console.log(e)
          alert('Failed to save name.')
        }
      }

    _retrieveData = async () => {
        console.log('trying to call data')
        try {
          const enableAuto = await AsyncStorage.getItem('STORAGE_KEY');
          console.log(enableAuto)
          if (enableAuto !== null) {
            // We have data!!
            console.log(enableAuto);
          }
        } catch (error) {
            alert('failed to load previous settings.')
          // Error retrieving data
        }
    };

   ...

   <Button title={'Store Data'} onPress={() => this._storeData(this.state.enableAuto)}/>
                        <Button title={'call Data'} onPress={() => this._retrieveData()}/>
                    </View>    
                        <View>
                            <CheckBox
                                value={this.state.enableAuto}
                                onValueChange={() => this.setState({ checked: !this.state.enableAuto })}
                            />

what is the type of data that you are storing? is it other than string? — Gaurav Roy
– Gaurav Roy, Commented Dec 28, 2019 at 6:09
as shown in the state, it's a boolean which I turn into a string to be able to store — LoF10
– LoF10, Commented Dec 28, 2019 at 6:15

Gaurav Roy · Accepted Answer · 2019-12-28 06:19:10Z

1

The error above is while you are storing, you are setting :

await AsyncStorage.setItem(STORAGE_KEY, x)

and here STORAGE_KEY refers to value @save_enableauto

But while you are retrieving data

const enableAuto = await AsyncStorage.getItem('STORAGE_KEY');

you are giving 'STORAGE_KEY' as string , so that means its refering 'STORAGE_KEY' and it doesnt have any stored value. Try this

const enableAuto = await AsyncStorage.getItem(STORAGE_KEY);

Hope it helps. feel free for doubts

answered Dec 28, 2019 at 6:19

Gaurav Roy

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4 Comments

LoF10 Over a year ago

Yeah this makes sense. I implemented your suggestion and now I am console logging [object Undefined]. Is this simply an unresolved promise or is there something else amiss here? Thanks.

Gaurav Roy Over a year ago

can you console.log x before storing it in asyncstorage?

LoF10 Over a year ago

ahh yeah i'm seeing now it's sending an undefined object. The state is true when I check my checkbox, then I press store data and it fires true. The thing is if I don't try to stringify the object I get the following error: java.lang.Boolean cannot be cast to java.lang.String - node_modules/react-native/Libraries/Storage/AsyncStorage.js:347:24 in convertError

Gaurav Roy Over a year ago

try to store like if(enableAuto){await AsyncStorage.setItem(STORAGE_KEY, 'true)} else {await AsyncStorage.setItem(STORAGE_KEY, 'false')}

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