Javascript 有没有办法导出默认的2个常量?
注:我是一个初学者,以英语为母语。我有两个js文件(Inputs.js和Styles.js),我试图将它们都放在主js文件(App.js)的Javascript 有没有办法导出默认的2个常量?,javascript,ios,react-native,expo,Javascript,Ios,React Native,Expo,注:我是一个初学者,以英语为母语。我有两个js文件(Inputs.js和Styles.js),我试图将它们都放在主js文件(App.js)的常量中,但我只能导出其中一个默认值。是否有一种方法可以同时导出这两种代码,还是应该以另一种方式重新排列代码 App.js: import React from 'react'; import { StyleSheet, Text, View } from 'react-native'; const Home1 = () => { return
常量中,但我只能导出其中一个默认值。是否有一种方法可以同时导出这两种代码,还是应该以另一种方式重新排列代码
App.js:
import React from 'react';
import { StyleSheet, Text, View } from 'react-native';
const Home1 = () => {
return (
<Style/>
)
}
const Home2 = () =>{
return (
<Inputs />
)
}
export default Home1; //I am unable to export both Home1 and Home2 here
import React, { Component } from 'react';
import { View, Text, Image, StyleSheet } from 'react-native'
const Style = () => {
return ( <View style = {styles.container}>
<Text style = {styles.text}>
<Text style = {styles.capitalLetter}>
Title Here
</Text>
<Text>
<Text style = {styles.textInput}> {"\n"} {"\n"}{"\n"}Location: </Text>
</Text>
<Text>
<Text style = {styles.textInput}> {"\n"} {"\n"}Time:</Text>
</Text>
<Text>
<Text style = {styles.textInput}> {"\n"} {"\n"}Time: </Text>
</Text>
</Text>
</View>
)
}
export default Style
const styles = StyleSheet.create ({
container: {
//alignItems: 'center',
marginTop: 50,
},
text: {
color: '#41cdf4',
},
capitalLetter: {
color: 'red',
fontSize: 20
},
textInput: {
padding: 22,
//fontWeight: 'bold',
color: 'black'
},
textShadow: {
textShadowColor: 'red',
textShadowOffset: { width: 2, height: 2 },
textShadowRadius : 5
}
})
import React, { Component } from 'react'
import { View, Text, TouchableOpacity, TextInput, StyleSheet } from 'react-native'
class Inputs extends Component {
state = {
email: '',
password: ''
}
handleEmail = (text) => {
this.setState({ email: text })
}
handlePassword = (text) => {
this.setState({ password: text })
}
login = (email, pass) => {
alert('email: ' + email + ' password: ' + pass)
}
render(){
return (
<View style = {styles.container}>
<TextInput style = {styles.input}
underlineColorAndroid = "transparent"
placeholder = "Email"
placeholderTextColor = "#9a73ef"
autoCapitalize = "none"
onChangeText = {this.handleEmail}/>
<TextInput style = {styles.input}
underlineColorAndroid = "transparent"
placeholder = "Password"
placeholderTextColor = "#9a73ef"
autoCapitalize = "none"
onChangeText = {this.handlePassword}/>
<TouchableOpacity
style = {styles.submitButton}
onPress = { () => this.login(this.state.email, this.state.password)}>
<Text style = {styles.submitButtonText}>
Submit
</Text>
</TouchableOpacity>
</View>
)
}
}
export default Inputs
const styles = StyleSheet.create({
container: {
paddingTop: 200
},
input: {
margin: 15,
height: 40,
borderColor: '#7a42f4',
borderWidth: 1
},
submitButton: {
backgroundColor: '#7a42f4',
padding: 10,
margin: 15,
height: 40,
},
submitButtonText:{
color: 'white'
}
})
import React from 'react';
import { StyleSheet, Text, View } from 'react-native';
module.exports = {
Home1() {
return (
<Style/>
);
},
Home2() {
return (
<Inputs/>
);
}
};
Style.js
import React, { Component } from 'react';
import { View, Text, Image, StyleSheet } from 'react-native'
import { Inputs } from "./App.js"
import Home1, {Home2} from './App.js'
const Style = () => {
return ( <View style = {styles.container}>
<Text style = {styles.text}>
<Text style = {styles.capitalLetter}>
Title Here
</Text>
<Text>
<Text style = {styles.textInput}> {"\n"} {"\n"}{"\n"}Your address or location (eg, Nashville, TN): </Text>
</Text>
<Text>
<Text style = {styles.textInput}> {"\n"} {"\n"}Contact 2:</Text>
</Text>
<Text>
<Text style = {styles.textInput}> {"\n"} {"\n"}Contact 3: </Text>
</Text>
</Text>
</View>
)
}
export default Style
const styles = StyleSheet.create ({
container: {
//alignItems: 'center',
marginTop: 50,
},
text: {
color: '#41cdf4',
},
capitalLetter: {
color: 'red',
fontSize: 20
},
textInput: {
padding: 22,
//fontWeight: 'bold',
color: 'black'
},
textShadow: {
textShadowColor: 'red',
textShadowOffset: { width: 2, height: 2 },
textShadowRadius : 5
}
})
import React, { Component } from 'react'
import { View, Text, TouchableOpacity, TextInput, StyleSheet } from 'react-native'
//import { Style } from "./App.js"
import Home1, {Home2} from './App.js'
class Inputs extends Component {
state = {
email: '',
password: ''
}
handleEmail = (text) => {
this.setState({ Location: text })
}
handlePassword = (text) => {
this.setState({ Time: text })
}
login = (email, time1) => {
alert('Location: ' + email + ' Time: ' + time1)
}
render(){
return (
<View style = {styles.container}>
<TextInput style = {styles.input}
underlineColorAndroid = "transparent"
placeholder = "Location"
placeholderTextColor = "#9a73ef"
autoCapitalize = "none"
onChangeText = {this.handleEmail}/>
<TextInput style = {styles.input}
underlineColorAndroid = "transparent"
placeholder = "Time"
placeholderTextColor = "#9a73ef"
autoCapitalize = "none"
onChangeText = {this.handlePassword}/>
<TouchableOpacity
style = {styles.submitButton}
onPress = { () => this.login(this.state.email, this.state.password)}>
<Text style = {styles.submitButtonText}>
Submit
</Text>
</TouchableOpacity>
</View>
)
}
}
export default Inputs
const styles = StyleSheet.create({
container: {
paddingTop: 200
},
input: {
margin: 15,
height: 40,
borderColor: '#7a42f4',
borderWidth: 1
},
submitButton: {
backgroundColor: '#7a42f4',
padding: 10,
margin: 15,
height: 40,
},
submitButtonText:{
color: 'white'
}
})
import React,{Component}来自'React';
从“react native”导入{视图、文本、图像、样式表}
从“/App.js”导入{Inputs}
从“/App.js”导入Home1,{Home2}
常量样式=()=>{
报税表(
标题在这里
{“\n”}{“\n”}{\n}您的地址或位置(如田纳西州纳什维尔):
{“\n”}{“\n”}联系人2:
{“\n”}{“\n”}联系人3:
)
}
导出默认样式
const styles=StyleSheet.create({
容器:{
//对齐项目:“居中”,
玛金托普:50,
},
正文:{
颜色:“#41cdf4”,
},
capitalLetter:{
颜色:“红色”,
尺寸:20
},
文本输入:{
填充:22,
//fontWeight:'粗体',
颜色:“黑色”
},
文本阴影:{
textShadowColor:'红色',
textShadowOffset:{宽度:2,高度:2},
文本阴影半径:5
}
})
Inputs.js
import React, { Component } from 'react';
import { View, Text, Image, StyleSheet } from 'react-native'
import { Inputs } from "./App.js"
import Home1, {Home2} from './App.js'
const Style = () => {
return ( <View style = {styles.container}>
<Text style = {styles.text}>
<Text style = {styles.capitalLetter}>
Title Here
</Text>
<Text>
<Text style = {styles.textInput}> {"\n"} {"\n"}{"\n"}Your address or location (eg, Nashville, TN): </Text>
</Text>
<Text>
<Text style = {styles.textInput}> {"\n"} {"\n"}Contact 2:</Text>
</Text>
<Text>
<Text style = {styles.textInput}> {"\n"} {"\n"}Contact 3: </Text>
</Text>
</Text>
</View>
)
}
export default Style
const styles = StyleSheet.create ({
container: {
//alignItems: 'center',
marginTop: 50,
},
text: {
color: '#41cdf4',
},
capitalLetter: {
color: 'red',
fontSize: 20
},
textInput: {
padding: 22,
//fontWeight: 'bold',
color: 'black'
},
textShadow: {
textShadowColor: 'red',
textShadowOffset: { width: 2, height: 2 },
textShadowRadius : 5
}
})
import React, { Component } from 'react'
import { View, Text, TouchableOpacity, TextInput, StyleSheet } from 'react-native'
//import { Style } from "./App.js"
import Home1, {Home2} from './App.js'
class Inputs extends Component {
state = {
email: '',
password: ''
}
handleEmail = (text) => {
this.setState({ Location: text })
}
handlePassword = (text) => {
this.setState({ Time: text })
}
login = (email, time1) => {
alert('Location: ' + email + ' Time: ' + time1)
}
render(){
return (
<View style = {styles.container}>
<TextInput style = {styles.input}
underlineColorAndroid = "transparent"
placeholder = "Location"
placeholderTextColor = "#9a73ef"
autoCapitalize = "none"
onChangeText = {this.handleEmail}/>
<TextInput style = {styles.input}
underlineColorAndroid = "transparent"
placeholder = "Time"
placeholderTextColor = "#9a73ef"
autoCapitalize = "none"
onChangeText = {this.handlePassword}/>
<TouchableOpacity
style = {styles.submitButton}
onPress = { () => this.login(this.state.email, this.state.password)}>
<Text style = {styles.submitButtonText}>
Submit
</Text>
</TouchableOpacity>
</View>
)
}
}
export default Inputs
const styles = StyleSheet.create({
container: {
paddingTop: 200
},
input: {
margin: 15,
height: 40,
borderColor: '#7a42f4',
borderWidth: 1
},
submitButton: {
backgroundColor: '#7a42f4',
padding: 10,
margin: 15,
height: 40,
},
submitButtonText:{
color: 'white'
}
})
import React,{Component}来自“React”
从“react native”导入{View,Text,TouchableOpacity,TextInput,StyleSheet}
//从“/App.js”导入{Style}
从“/App.js”导入Home1,{Home2}
类输入扩展组件{
状态={
电子邮件:“”,
密码:“”
}
handleEmail=(文本)=>{
this.setState({Location:text})
}
handlePassword=(文本)=>{
this.setState({Time:text})
}
登录=(电子邮件,时间1)=>{
警报('位置:'+电子邮件+'时间:'+时间1)
}
render(){
返回(
this.login(this.state.email,this.state.password)}>
提交
)
}
}
导出默认输入
const styles=StyleSheet.create({
容器:{
加油站:200
},
输入:{
差额:15,
身高:40,
边框颜色:“#7a42f4”,
边框宽度:1
},
提交按钮:{
背景颜色:“#7a42f4”,
填充:10,
差额:15,
身高:40,
},
submitButtonText:{
颜色:“白色”
}
})
在本例中,您可以使用模块.exports
使用两种方法导出对象。用法:
export function Home1() {
return (
<Style/>
);
};
export function Home2() {
return (
<Inputs/>
);
};
在本例中,您使用的是命名导出。为了正确地导入它,您需要显式地使用import{Home1,Home2}
,Home1和Home2是导出函数的对应名称 您可以只使用一个默认导出和所需的任意多个导出:
const Home1 = () => {
return <Style/>
}
export const Home2 = () => {
return <Inputs />
}
export default Home1;
创建一个组件,如下图所示,它可以工作,并显示应用程序中的Style.js和Inputs.js文件:
import React, {Component} from 'react';
import { StyleSheet, Text, View, AppRegistry } from 'react-native';
import Style from './Style.js';
import Inputs from './Inputs.js';
export default class App extends Component {
render() {
return (
<View>
<Style/> // here, both the Style and Inputs files can be used
<Inputs/>
</View>
)
}
}
import React,{Component}来自'React';
从“react native”导入{样式表、文本、视图、AppRegistry};
从“./Style.js”导入样式;
从“/Inputs.js”导入输入;
导出默认类应用程序扩展组件{
render(){
返回(
//在这里,可以使用样式和输入文件
)
}
}
您可以导出常量,但只能导出一个默认常量
import React from 'react';
export const myCon1 = (
// your code goes here
);
export const myCon2 = (
// your code goes here
);
在另一边你可以导入
import { myCon1 , myCon2} from '/path_to_file';
为什么不同时导出这两个文件,而不导出默认值?然后您可以这样导入:import{Style,Inputs}来自'/constant'
@AntoineGrandchamp那么你是说我应该创建一个名为constant的js文件,然后以某种方式将样式和输入文件结合起来?对不起,我想我误解了你的问题。看看@Tomasz Bubala的答案,它应该是你想要的need@AntoineGrandchamp我已经审阅了@Tomasz Bubała的答案,但是我收到了一个错误:元素类型无效:应该是字符串(对于内置组件)或类/函数(对于复合组件),但得到了:object。
我试着问写答案的人,但此人目前处于脱机状态。如果您只是想将其导出,那么将其导入app.js有什么意义?您在哪里使用这些?我遇到了一个错误:元素类型无效:需要字符串(对于内置组件)或类/函数(对于复合组件),但得到了:object。
可能是因为我在两个方法中的每个方法中都放错了信息。我把和以前一样的东西放在了return中,甚至是你在答案中所做的编辑,我仍然会得到同样的错误。我只是让Style.js文件显示在我的应用程序中。我在Style.js和Inputs.js文件中使用了导入方法,并在App.js文件中输入了您给出的第一组代码。我做错什么了吗?你可以用一个标题或段落之类的东西来替换没有显示的组件,看看它是否首先呈现得很好。然后,在它出现之后,您可以将代码放回原处并进一步调查;)为什么要在App.js中执行此操作,而不仅仅是