我有一些文件可以导出对象以用作模型。在某些对象中，我使用另一个文件中的模型。只要另一个模型不使用另一个文件，此方法就可以正常工作，但是如果另一个模型不使用另一个文件，则该文件变为import React, {Component} from 'react'
import {
Alert,
AsyncStorage,
Keyboard,
Text,
View,
TextInput,
TouchableHighlight, TouchableOpacity,
Image,
ActivityIndicator,
} from 'react-native'
import config from "../../../../config";
import styles from './style'
import {Icon} from "react-native-elements";
class Login extends Component {
constructor(props) {
super(props);
this.state = {
credentials: {
email: "",
password: "",
},
loading: false,
};
this.toggleLoader = this.toggleLoader.bind(this);
}
updateText(text, field) {
let newCredentials = Object.assign(this.state.credentials);
newCredentials[field] = text;
this.setState = ({
credentials: newCredentials
})
}
toggleLoader() {
this.setState({
loading: !this.state.loading
});
}
async login() {
Keyboard.dismiss();
let credentials = this.state.credentials;
if (this.state.credentials.email == '' || this.state.credentials.password == '') {
Alert.alert("Please fill all the fields.");
} else {
const that = this;
credentials.email = that.state.credentials.email.toLowerCase();
// start loading when all fields are fill
this.setState({ loading: !this.state.loading });
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 => {
//stop loading after successful response
this.setState({ loading: !this.state.loading });
if (responseJson.confirmation === "success") {
// alert(JSON.stringify(responseJson.data));
AsyncStorage.setItem('USER_ID', responseJson.data.user_id);
AsyncStorage.setItem('USER_NAME', responseJson.data.user_name);
AsyncStorage.setItem('USER_TYPE', responseJson.data.user_type);
AsyncStorage.setItem('FIRST_NAME', responseJson.data.first_name);
AsyncStorage.setItem('LAST_NAME', responseJson.data.last_name);
AsyncStorage.setItem('EMAIL', responseJson.data.user_email);
AsyncStorage.setItem('AUTHENTICATION_TOKEN', responseJson.data.token);
setTimeout(() => {
this.props.navigation.navigate("Home")
}, 500);
} else {
setTimeout(() => {
//code to handle an error
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')) {
alert('Please check your internet connection or try again later');
} else {
alert(JSON.stringify(err.message));
}
}, 500);
})
}
}
render() {
const loginText = (this.state.loader) ? 'Loading' : 'Login';
return (
<View style={styles.container}>
<Image source={require('../../../../assets/images/icons/logo.png')}
style={{width: 99, height: 99, margin: 5,}}/>
<Text style={{fontSize: 20, margin: 20, color: "#0aa1e2"}}>Test App</Text>
<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;
。我认为这是由于循环引用，因此为避免混乱，它会废弃其中一个引用。
这是一个愚蠢的例子：
undefined这有可能吗？