Firebase + React Native - Grab each Document ID

问题

I have been stuck on this for ages trying to figure out how I can console log each Firebase Cloudstore document ID separately when I press onto each rendered FlatList item.

I can grab a certain key / id by using onPress={() =>{console.log(this.state.posts[0].key)}} etc. But I dont know how to grab each one separately. In essence I only want the document ID of the touchableOpacity I have pressed. Not just [0]

Screenshots are below of App layout so you can get an understanding and also code example

PostsLayout.js

export default class PostsLayout extends React.Component {

  render() { 
    const {summary, stringTime, user} = this.props;

    return (         

        <TouchableOpacity 
          style={styles.container}
          onPress={this.props.onPress} 
        >
            <PostsUser user={user}/>
            <PostsSummary summary={summary}/>
            <PostsDate time={stringTime}/>
        </TouchableOpacity>
    )
  }
}

FlatListLayout.js

    export default class FlatListLayout extends React.Component { 

    render() { 
        return ( 
                <ScrollView >
                    <FlatList 
                        data={this.props.data}
                        renderItem={({item}) => <PostsLayout {...item} onPress={this.props.onPress}/>}
                    />
                </ScrollView>
        )
    }
}

ScreenLayout.js

export default class ScreenLayout extends React.Component { 

    state = {
        posts: []
    }

    db = firebase.firestore()
    path = this.db.collection('usersData').doc(firebase.auth().currentUser.uid).collection("posts")


    onCollectionUpdate = (querySnapshot) => {
        const posts = [];    
            querySnapshot.forEach((doc) => { 
                const {summary, time, stringTime, user, userId} = doc.data();

                posts.push({
                    key: doc.id, doc, summary,
                    time, stringTime, user, userId
                });
            });

            this.setState({
                posts
            });

    }

    componentDidMount() {
        const {currentUser} = firebase.auth();
        this.setState({currentUser})

        this.unsubscribe = this.path.onSnapshot(this.onCollectionUpdate) 
    }

    componentWillUnmount() {
        this.unsubscribe(); 
    }

    render() { 
        return ( 
        <FlatListLayout
            data={this.state.posts}
            onPress={() => {console.log(this.state.posts[0].key)}}
        />
        )
    }
}

Thank you for reading this and please help :)

回答1:

So the easiest fix would be send a function argument from the original press event in the child level. For example, PostsLayout has the main onPress, so on this call just send back any data you need, each component will have specific data related to the component. As each react child is unique. PostsLayout.js

export default class PostsLayout extends React.Component {

  handleOnPress = () => {
   const { onPress, index } = this.props;
   if( typeof onPress === 'function') {
     onPress(this.props, index); // here pass anything you want in the parent level, like even userm stringtime etc
   }
  }

  render() { 
    const {summary, stringTime, user} = this.props;

    return (         

        <TouchableOpacity 
          style={styles.container}
          onPress={this.handleOnPress} 
        >
            <PostsUser user={user}/>
            <PostsSummary summary={summary}/>
            <PostsDate time={stringTime}/>
        </TouchableOpacity>
    )
  }
}

FlatListLayout.js

    export default class FlatListLayout extends React.Component { 

    render() { 
        return ( 
                <ScrollView >
                    <FlatList 
                        data={this.props.data}
                        renderItem={({item, index }) => <PostsLayout {...item} index={index} onPress={this.props.onPress}/>}
                    />
                </ScrollView>
        )
    }
}

ScreenLayout.js

export default class ScreenLayout extends React.Component { 

    state = {
        posts: []
    }

    db = firebase.firestore()
    path = this.db.collection('usersData').doc(firebase.auth().currentUser.uid).collection("posts")


    onCollectionUpdate = (querySnapshot) => {
        const posts = [];    
            querySnapshot.forEach((doc) => { 
                const {summary, time, stringTime, user, userId} = doc.data();

                posts.push({
                    key: doc.id, doc, summary,
                    time, stringTime, user, userId
                });
            });

            this.setState({
                posts
            });

    }

    componentDidMount() {
        const {currentUser} = firebase.auth();
        this.setState({currentUser})

        this.unsubscribe = this.path.onSnapshot(this.onCollectionUpdate) 
    }

    componentWillUnmount() {
        this.unsubscribe(); 
    }

    render() { 
        return ( 
        <FlatListLayout
            data={this.state.posts}
            onPress={(data, index) => {console.log(data); console.log(this.state.posts[index].key)}}
        />
        )
    }
}

Let me know if this doesn't make any sense :)

来源：https://stackoverflow.com/questions/54842905/firebase-react-native-grab-each-document-id