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[英]undefined is not an object (evaluating 'item.phoneNumbers[0]')
[英]typeError: undefined is not an object (evaluating 'item.phoneNumbers[0]')
我想使用 expo-contacts 在我的应用程序中呈现我的联系人列表,列表显示大约 2 秒,然后我得到 typeError: undefined is not an object(评估“item.phoneNumbers[0]”)。 我检查了文档以查看是否有任何错误,但我找不到任何错误。 有没有人解决这个问题
下面是我的代码
联系人列表.js
import React, { Component } from "react";
import {
View,
Text,
Platform,
StatusBar,
FlatList,
StyleSheet,
ActivityIndicator
} from "react-native";
import * as Contacts from "expo-contacts";
import * as Permissions from "expo-permissions";
class ContactList extends Component {
static navigationOptions = {
header: null
};
constructor(props) {
super(props);
this.state = {
isLoading: false,
contacts: []
};
}
async componentDidMount() {
this.setState({
isLoading: true
});
this.loadContacts();
}
loadContacts = async () => {
const permissions = await Permissions.askAsync(Permissions.CONTACTS);
if (permissions.status !== "granted") {
return;
}
const { data } = await Contacts.getContactsAsync({
fields: [Contacts.Fields.PhoneNumbers, Contacts.Fields.Emails]
});
this.setState({
contacts: data,
isLoading: false
});
};
handleBack() {
this.props.navigation.goBack();
}
renderItem = ({ item }) => (
<View style={{ minHeight: 70, padding: 5 }}>
<Text>
{item.firstName}
{item.lastName}
</Text>
<Text>{item.phoneNumbers[0].digits}</Text>
</View>
);
render() {
const { isLoading, contacts } = this.state;
let emptyContact = null;
emptyContact = (
<View style={styles.emptyContactStyle}>
<Text style={{ color: "red" }}>No Contacts Found</Text>
</View>
);
return (
<SafeAreaView style={styles.contentWrapper}>
<View style={styles.contentWrapper}>
{isLoading ? (
<View style={styles.isLoadingStyle}>
<ActivityIndicator size="large" color="#2484E8" />
</View>
) : null}
<FlatList
data={contacts}
renderItem={this.renderItem}
keyExtractor={(item, index) => index.toString()}
ListEmptyComponent={emptyContact}
/>
</View>
</SafeAreaView>
);
}
}
这是一个新的答案,因为上一个答案是题外话。 发生错误是因为显示的联系人没有phoneNumber
。
在显示之前,您应该首先检查电话号码是否存在:
renderItem = ({ item }) => (
<View style={{ minHeight: 70, padding: 5 }}>
<Text>
{item.firstName}
{item.lastName}
</Text>
<Text>
{item.phoneNumbers && item.phoneNumbers[0] && item.phoneNumbers[0].digits}
</Text>
</View>
);
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