我正在为单个应用设置子域URL。子域名将在第一次输入。它保存到异步存储中，并且需要从通用组件中检索它
使用const不能正常工作。
这是部分完成的代码。在另一个组件函数内部需要baseURL和socketURL。如何从那里访问这些常量？
index_new.js
import * as React from 'react';
import { View } from 'react-native';
import AsyncStorage from '@react-native-community/async-storage';
import Login from "../screens/common/login/login/login";
export default class App extends React.Component {
constructor(props) {
super(props);
this.state = {
sub_domain: '',
};
}
async getSchoolCode() {
let sub_domain = '';
try {
sub_domain = await AsyncStorage.getItem('SCHOOL_CODE') || ''
} catch (error) {
}
return sub_domain;
};
async setSubdomain() {
const sub_domain = await this.getschoolcode()
await this.setState({ sub_domain })
}
getBaseUrl() {
return `http://${this.state.sub_domain}.vidhyadhan.in:81/`;
}
getSocketIoUrl() {
return `http://${this.state.sub_domain}.vidhyadhan.in:8080/`;
}
async componentDidMount() {
await this.setSubdomain();
}
render() {
const baseUrl = this.getBaseUrl();
const socketIoUrl = this.getSocketIoUrl();
const extraProps = {
baseUrl,
socketIoUrl
}
return (
<View>
<Login {...extraProps} />
</View>
)
}
}
Login.js
import React, { Component } from 'react'
import {
Alert,
Keyboard,
Text,
View,
TextInput,
TouchableHighlight,
Image,
ActivityIndicator,
StatusBar,
} from 'react-native'
import config from "../../../../config";
import styles from './style'
import { Icon } from "react-native-elements";
import Toaster from '../../../../components/toaster'
import AsyncStorage from '@react-native-community/async-storage';
class Login extends Component {
constructor(props) {
super(props);
this.state = {
credentials: {
schoolcode: "",
email: "",
password: "",
},
loading: false,
school_code: '',
};
}
async getschoolcode() {
let school_code = '';
try {
school_code = await AsyncStorage.getItem('SCHOOL_CODE') || ''
} catch (error) {
}
return school_code;
};
updateText(text, field) {
let newCredentials = Object.assign(this.state.credentials);
newCredentials[field] = text;
// setState should be done like this
this.setState({
credentials: newCredentials
})
if(field == 'schoolcode'){
AsyncStorage.setItem('SCHOOL_CODE', text);
this.getschoolcode().then((keyValue) => {
this.state.school_code = keyValue;
console.log(this.state.school_code);
});
}
}
async login() {
Keyboard.dismiss();
let credentials = this.state.credentials;
if (this.state.credentials.schoolcode == '' || this.state.credentials.email == '' || this.state.credentials.password == '') {
Toaster.toast('Please Enter a valid UserName and Password', '#d30000')
} else {
const that = this;
credentials.email = that.state.credentials.email;
this.setState({ loading: !this.state.loading });
const new_url = this.props.baseUrl;
fetch(config.baseURL + 'mobileapi/get_token/?username=' + `${that.state.credentials.email}` + '&password=' + `${that.state.credentials.password}`, {
method: 'POST',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({
credentials: credentials,
}),
})
.then((response) => response.json())
.then(responseJson => {
if (responseJson.confirmation === "success") {
AsyncStorage.setItem('USER_ID', responseJson.data.user_id.toString());
this.setState({ loading: !this.state.loading });
setTimeout(() => {
this.props.navigation.navigate("Home")
}, 500);
} else {
this.setState({ loading: !this.state.loading });
setTimeout(() => {
Toaster.toast('Please Enter a valid UserName and Password', '#d30000')
// throw new Error(responseJson.message);
}, 500);
}
})
.catch((err) => {
//stop loading
this.setState({ loading: !this.state.loading });
setTimeout(() => {
if (JSON.stringify(err.message) === JSON.stringify('Network request failed')) {
Toaster.toast('Please check your internet connection or try again later', '#d30000')
}
}, 500);
})
}
}
render() {
const loginText = (this.state.loading) ? 'Loading' : 'Login';
return (
<View style={styles.container}>
<StatusBar backgroundColor="#2383c9"
translucent={true}
hidden={false}/>
<Image source={require('../../../../assets/images/icons/logo.png')}
style={{ width: 99, height: 99, margin: 5, }} />
<Text style={{ fontSize: 20, margin: 20, color: "#ffffff" }}>Vidhyadhan</Text>
<View style={styles.inputContainer}>
<Image style={styles.inputIcon}
source={require('../../../../assets/images/icons/username.png')} />
<TextInput style={styles.inputs}
placeholder="School-Code"
underlineColorAndroid='transparent'
onChangeText={text => {
this.updateText(text, 'schoolcode')
}} value={this.state.schoolcode}
autoCorrect={false}
autoCapitalize={"none"}
/>
</View>
<View style={styles.inputContainer}>
<Image style={styles.inputIcon}
source={require('../../../../assets/images/icons/username.png')} />
<TextInput style={styles.inputs}
placeholder="Username"
keyboardType="email-address"
underlineColorAndroid='transparent'
onChangeText={text => {
this.updateText(text, 'email')
}} value={this.state.email}
autoCorrect={false}
autoCapitalize={"none"}
/>
</View>
<View style={styles.inputContainer}>
<Image style={styles.inputIcon}
source={require('../../../../assets/images/icons/password.png')} />
<TextInput style={styles.inputs}
placeholder="Password"
secureTextEntry={true}
underlineColorAndroid='transparent'
onChangeText={text => {
this.updateText(text, 'password')
}}
value={this.state.password}
autoCorrect={false}
secureTextEntry />
</View>
<TouchableHighlight style={[styles.buttonContainer, styles.loginButton]}
onPress={this.login.bind(this)} >
<View style={{ justifyContent: 'center', flex: 1, flexDirection: 'row' }}>
{this.state.loading === false ?
<Icon name='login' type='entypo' size={16} color='white' /> :
<ActivityIndicator size="small" color="#ffffff" />}
<Text style={styles.loginText}> {loginText} </Text>
</View>
</TouchableHighlight>
</View>
);
}
}
export default Login;
答案 0 :(得分：0)
首先，您没有正确设置状态。然后，您尝试两次设置状态。
这是一种更好的方法：
import * as React from 'react';
import { View } from 'react-native';
import AsyncStorage from '@react-native-community/async-storage';
export default class App extends React.Component {
constructor(props) {
super(props);
this.state = {
sub_domain: '',
};
}
async getSchoolCode() {
let sub_domain = '';
try {
sub_domain = await AsyncStorage.getItem('sub_domain') || ''
} catch (error) {
}
return sub_domain;
};
async setSubdomain() {
const sub_domain = await this.getschoolcode()
await this.setState({ sub_domain })
}
getBaseUrl() {
return `http://${this.state.sub_domain}.vidhyadhan.in:81/`;
}
getSocketIoUrl() {
return `http://${this.state.sub_domain}.vidhyadhan.in:8080/`;
}
async componentDidMount() {
await this.setSubdomain();
}
render() {
const baseUrl = this.getBaseUrl();
const socketIoUrl = this.getSocketIoUrl();
return (
<View/>
);
}
}
根据评论，您的渲染方式如下：
render() {
const baseUrl = this.getBaseUrl();
const socketIoUrl = this.getSocketIoUrl();
const extraProps = {
baseUrl,
socketIoUrl
}
return (
<View>
<MyFirstComponent {...extraProps} />
<MySecondComponent {...extraProps} />
</View>
)
}
在MyFirstComponent中，您可以使用this.props.baseUrl或this.props.socketIoUrl