我尝试重新渲染平面列表，但无法再更新，
我从实时数据库获取数据并将其作为数据 Prop 传递给 Flatlist， 并编写一个函数来从列表和数据库中删除一个项目并且工作得很好，但是当我删除列表中的最后一个项目时，我看不到空屏幕“列表”，只是保存了我删除的最后一个项目，尽管它已被删除在数据库中!
代码
import React, { Component } from 'react';
import { View, Text, StyleSheet, FlatList, ScrollView, TouchableOpacity } from 'react-native';
import firebase from "react-native-firebase";
import Icon from 'react-native-vector-icons/Ionicons';
class UserFavorites extends Component {
constructor(props) {
super(props);
this.state = {
currentUser: null,
favorites: [],
}
}
componentDidMount() {
const currentUser = firebase.auth().currentUser.uid;
this.setState({ currentUser });
const favorites = firebase.database().ref(`favorites/${currentUser}`);
favorites.on("value", (snapshot) => {
let favorites = []
snapshot.forEach((childSnapshot) => {
favorites.push({
ProviderId: childSnapshot.val().ProviderId,
providerName: childSnapshot.val().providerName,
providerService: childSnapshot.val().providerService,
});
this.setState({ favorites })
});
});
}
_listEmptyComponent = () => {
return (
<View style={styles.container}>
<Text style={{ alignSelf: "center" }}> No favorites Provider Found :O</Text>
</View>
)
}
render() {
const { fav } = this.state;
return (
<View style={styles.container} >
<FlatList data={this.state.favorites}
key={Math.random() * 1000}
contentContainerStyle={{ flexGrow: 1 }}
ListEmptyComponent={this._listEmptyComponent()}
extraData={this.state}
renderItem={({ item }) => {
return (
<ScrollView>
<TouchableOpacity>
<View
style={{
flex: 1,
paddingLeft: 15,
paddingRight: 10,
height: 105,
alignItems: "center",
backgroundColor: "#fafafa",
flexDirection: "row",
borderBottomWidth: .8,
borderBottomColor: "#aaa"
}}>
<Icon style={{ alignSelf: "center" }} name="ios-contact" size={60} color="#1567d3" />
<View style={{ flex: 1, padding: 5, flexDirection: "row" }}>
<View style={{ marginLeft: 27 }}>
<Text style={{
fontSize: 18,
fontWeight: "800",
fontFamily: 'Gill Sans',
color: '#000',
}}>
{item.providerName}
</Text>
<Text style={{
fontSize: 18,
fontWeight: "800",
fontFamily: 'Gill Sans',
color: '#000',
}}>
{item.providerService}
</Text>
</View>
<View style={{ alignItems: "flex-end", justifyContent: "center", flex: 1 }}>
<Icon style={{ marginRight: 20 }}
name={`ios-heart${fav ? "" : "-empty"}`}
size={35} color="#f00"
onPress={() => {
const currentUser = firebase.auth().currentUser.uid;
firebase.database().ref(`favorites/${currentUser}/${item.ProviderId}`).remove().then(() => alert("Removed"))
}}
/>
</View>
</View>
</View>
</TouchableOpacity>
</ScrollView>
)
}
}
keyExtractor={(item, index) => index.toString()}
/>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
},
});
export default UserFavorites;
最佳答案
您要从 Firebase 中删除该项目，而不是从 Flatlist 的数据源 this.state.favorites 中删除该项目，请添加一个在从 Firebase 中删除该项目后调用的函数。
_onRemove = (_item) => {
this.setState({
favorites: this.state.favorites.filter(item => item.ProviderId !== _item.ProviderId)
});
}
将要删除的项目传递给平面列表中的函数
renderItem={({ item }) => {
return ....
//scrollview code
<Icon style={{ marginRight: 20 }}
name={`ios-heart${fav ? "" : "-empty"}`}
size={35} color="#f00"
onPress={() => {
const currentUser = firebase.auth().currentUser.uid;
....
// firebase code
this._onRemove(item);
}
/>
....
//rest of the code
}}
关于javascript - 尽管使用 extraData，但删除最后一项后无法重新渲染 FlatList - React Native，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/56611080/