如何使用道具中的数据调用 setState？ 反应本机

Question

I have a component Home that is called after user get in. There are some data in that screen, and in the header I have a icon button that send the user for a screen where the user can see their profile data and also delete account. So when the icon button is clicked I'm sending data using props.navigation , sending the user to another screen/component.

profile = () => {
        const { navigation } = this.props;
        const user = navigation.getParam('user', 'erro');
        this.props.navigation.navigate('profileScreen', { user: user });
    }

Inside the new component, I tried to setState inside the method componentDidMount using that data but it didn't work. I checked using console.log the data is there. How could I setState in this case?

export default class profileScreen extends Component {
    static navigationOptions = {
        title: "Profile"
    };

constructor(props) {
    super(props);
    this.state = {
        user: {}
    }
}

componentDidMount() {
    const {navigation} = this.props;
    const user = navigation.getParam('user', 'Erro2');
    this.setState({user: user.user});
    console.log(this.state); // Object {"user": Object {},}
    console.log("const user");
    console.log(user.user); //my actual data is printed
}

render() {
    return (
        <Text>{this.state.use.name}</Text>
        <Text>{this.state.use.age}</Text>
        <Text>{this.state.use.email}</Text>
        ...
        ...
    )
}

}

Result from console.log(this.state)

Object {
  "user": Object {},
}

Result from console.log(user)

Object {
  "createdAt": "2019-04-27T21:21:36.000Z",
  "email": "sd@sd",
  "type": "Admin",
  "updatedAt": "2019-04-27T21:21:36.000Z",
  ...
  ...
}

Answer 1

It seems like you're trying to send an object ( user ) as a route parameter with react-navigation library. It's not possible.

The proper way of doing such scenarios is to send the user's id userId as route parameter and load user details from your API (or state).

profile = () => {
        const user = {id: 10 /*, ... rest of properties */}; // or take it from your state / api
        this.props.navigation.navigate('profileScreen', { userId: user.id });
    }



componentDidMount() {
    const {navigation} = this.props;
    const userId = navigation.getParam('userId', 'Erro2');
    // const user = read user details from state / api by providing her id
    this.setState({user: user});
}

ps: if you are using state management like redux/flux/..., consider setting currentUser in your global state and read that instead of passing userId as a route param.

To make sure component updates when the user got new value in the state render method should be like this:

render() {
    const {user} = this.state
    return (
      <View>
        {user && <Text>{user.name}</Text>}
        {user && <Text>{user.age}</Text>}
        {user && <Text>{user.email}</Text>}
        ...
        ...
     </View>
    )
}

Note 0: const {user} = this.state would save you from repeating this.state

Note 1: it would much more elegant to wrap all those <Text> component inside another <View> to prevent repeating the condition phrase {user && ...}