React native TypeError:undefined不是对象(评估';资产.比例';)
我对React Native非常陌生,但我正在尝试使用React native TypeError:undefined不是对象(评估';资产.比例';),react-native,React Native,我对React Native非常陌生,但我正在尝试使用ImageBackground组件添加png作为背景图像。我的项目目录中的“资产”文件夹中有png。当我在iPhone上运行带有Expo的应用程序时,出现以下错误: 这是我的代码: import React, {useState, Component} from 'react'; import {StyleSheet, Text, View, TextInput, TouchableOpacity, Image} from 'react-n
ImageBackground
组件添加png作为背景图像。我的项目目录中的“资产”文件夹中有png。当我在iPhone上运行带有Expo的应用程序时,出现以下错误:
这是我的代码:
import React, {useState, Component} from 'react';
import {StyleSheet, Text, View, TextInput, TouchableOpacity, Image} from 'react-native';
import * as Font from "expo-font";
import {ImageBackground} from "react-native-web";
class LoginPage extends Component {
state = {
fontLoaded: false,
};
async componentDidMount() {
await Font.loadAsync({
'Veles-Regular' : require("./assets/fonts/Veles-Regular.otf"),
});
console.log('HI');
this.setState({fontLoaded: true});
}
render() {
return (
<ImageBackground source={require('./assets/login_splash.png')} style={{width: 100, height: 100}}>
<View style={styles.loginScreen}>
<View style={{flex: 1, justifyContent: 'center'}}>
{
this.state.fontLoaded ? (
<Text style={{fontSize: 60, color: 'white', fontFamily: 'Veles-Regular'}}>App Name</Text>
) : null
}
</View>
<View style={{flex: 1, justifyContent: 'center', alignItems: 'center', width: '85%'}}>
<TextInput style={[styles.loginInput, {marginBottom: 5}]} placeholder=' username'
placeholderTextColor={'rgba(255,255,255,0.3)'} textAlign='center'/>
<TextInput style={[styles.loginInput, {marginTop: 5, marginBottom: 5}]} placeholder=' password'
placeholderTextColor={'rgba(255,255,255,0.3)'} textAlign='center'/>
<View style={{height: 15}}/>
<TouchableOpacity onPress={() => {
}}>
<Text style={{color: 'white', fontWeight: 'bold', fontSize: 24}}>Log in</Text>
</TouchableOpacity>
</View>
<View style={{flex: 2, justifyContent: 'center'}}>
<View style={{flex: 9}}/>
<Text style={{flex: 1, fontSize: 24, color: 'white', textAlign: 'center'}}>Don't have an
account?</Text>
<TouchableOpacity style={{color: 'white', fontWeight: 'bold', fontSize: 24}}>
<Text style={{color: 'white', fontWeight: 'bold', fontSize: 24, textAlign: 'center'}}>Sign
Up</Text>
</TouchableOpacity>
<View style={{height: 30}}/>
</View>
</View>
</ImageBackground>
);
}
}
const styles = StyleSheet.create({
loginScreen: {
flex: 1,
paddingTop: 50,
alignItems: 'center',
justifyContent: 'center',
},
loginInput: {
width: '100%',
backgroundColor: 'rgb(40,40,40)',
height: 44,
fontSize: 24,
color: 'white',
borderWidth: 1,
borderColor: 'rgb(60,60,60)',
borderRadius: 25
},
});
export default LoginPage;
import React,{useState,Component}来自'React';
从“react native”导入{样式表、文本、视图、文本输入、TouchableOpacity、图像};
从“expo字体”导入*作为字体;
从“react native web”导入{ImageBackground};
类LoginPage扩展组件{
状态={
错误:,
};
异步组件didmount(){
等待Font.loadAsync({
“Veles Regular”:要求(“./assets/font/Veles Regular.otf”),
});
console.log('HI');
this.setState({fontLoaded:true});
}
render(){
返回(
{
这是州政府吗(
应用程序名称
):null
}
{
}}>
登录
没有一个
账户
签名
向上的
);
}
}
const styles=StyleSheet.create({
登录筛选:{
弹性:1,
paddingTop:50,
对齐项目:“居中”,
为内容辩护:“中心”,
},
登录输入:{
宽度:“100%”,
背景颜色:“rgb(40,40,40)”,
身高:44,
尺寸:24,
颜色:'白色',
边框宽度:1,
边框颜色:“rgb(60,60,60)”,
边界半径:25
},
});
导出默认登录页面;
我也有类似的问题,包括“图像”组件和类似的错误“TypeError:undefined不是对象(评估“asset.scales”)。
这个问题的解决方案非常简单,更改:
import {ImageBackground} from "react-native-web";
致:
看起来我们从错误的包中导入了组件:)
import React, {useState, Component, ImageBackground} from 'react';