使用redux的react-native setstate

时间:2018-10-17 04:26:31

标签: javascript react-native redux react-redux

我正在尝试使用redux设置setState。我正在使用Facebook登录,一旦获得facebookAccessToken,我想使用redux将其设置为全局状态,然后使用按钮回调全局状态。下面是我的代码:

App.js

import { createStore } from 'redux'
import { Provider } from 'react-redux'
import { createDrawerNavigator, createStackNavigator, } from 'react-navigation'

const reducer = (state = '', action) => {
  switch (action.type) {
    case 'UPDATE':
            return { facebookToken: action.payload}
  }
    return state
}

const store = createStore(reducer)

class App extends Component {
  render(){
    return(

      <Provider store={store}>
        <View style={{flex:1,backgroundColor:'transparent'}}>
          <AppDrawerNavigator/>
        </View>
      </Provider> 
    )
  }
}

LoginScreen.js

    import { LoginButton, AccessToken } from 'react-native-fbsdk';
    import {connect} from 'react-redux'

    class LoginScreen extends Component{
    render() {
        return(

      <View>
                <LoginButton
                  onLoginFinished={
                    (error, result) => {
                      if (error) {
                        console.log("login has error: " + result.error);
                      } else if (result.isCancelled) {
                        console.log("login is cancelled.");
                      } else {
                        this.props.navigation.navigate('VerifyScreen')
                        AccessToken.getCurrentAccessToken().then(
                          (data) => {
                            this.setState({facebookToken:data.accessToken},
                        () =>  console.log('facebookToken.state',this.state.facebookToken),
    //Here I am getting undefined for 'this.props.facebookToken'                        
    () =>  console.log('facebookToken.props',this.props.facebookToken),
                            console.log('facebook login success!'),
                            console.log('facebook token is:',data.accessToken.toString()))
                          }
                        )
                      }
                    }
                  }
                  onLogoutFinished={() => console.log("logout.")}/>

    //I created a button to see if I could call global state. but this would give me an error "state is not defined"
    <Button
                title="call global state"
                onPress={() => this.props.updateState()}/>


    </View>
      )
   }
}

function mapStateToProps(state) {
    return {
        facebookToken: state.facebookToken
    }
}

function mapDispatchToProps(dispatch) {
    return {
        updateState: () => dispatch({ type: 'UPDATE',payload: state.facebookToken }),
    }
}

export default connect(mapStateToProps, mapDispatchToProps)(LoginScreen)

我的问题: 1)在我的LoginScreen中,为什么为什么要为我的{this.props.facebookToken}获取undefined是因为我没有调用函数“ updateState”?

2)成功登录Facebook后,在“登录屏幕”中,我得到AccessToken并假设this.props.facebookToken设置为data.accessToken。因此,当我按下按钮时,我期望得到globalState,但它给了我一个错误state的定义。

我真的是redux的新手,所以任何评论或建议都将非常有帮助。提前致谢!

1 个答案:

答案 0 :(得分:1)

对于您的#1问题,您是正确的,因为您没有调用updateState方法。

对于您的#2问题,请尝试此操作。该状态永远不会在该代码块中定义,因为您没有传递状态对象。

function mapDispatchToProps(dispatch) {
  return {
    updateState: () => dispatch({ type: 'UPDATE', payload: state.facebookToken }),
  } 
}

将其更改为

function mapDispatchToProps(dispatch) {
  return {
    updateState: (state) => dispatch({ type: 'UPDATE', payload: state.facebookToken }),
  } 
}

然后更改

onPress={() => this.props.updateState()}

onPress={() => this.props.updateState(this.state)}