React Native:TypeError:未定义不是对象(评估“this.props.navigation.navigate”)
2017-11-24
5601
作为 react-native 的新手,我无法找出代码中的问题。通过在网上阅读,我意识到我可能存在一些绑定问题。
因此,我的代码从 index.js 开始,并在那里注册 App 组件。app 组件仅包含堆栈导航路由。它加载 LoginScreen 组件(显示徽标、背景和应用程序名称),然后加载 LoginForm 组件。Login 按钮上没有身份验证,我唯一需要的是按下 Login 按钮时加载 Menu 组件。它给出了 TypeError:未定义不是一个对象(评估'this.props.navigation.navigate')
index.js
import { AppRegistry } from 'react-native';
import App from './App';
AppRegistry.registerComponent('bluebulk', () => App);
App.js
import { StackNavigator } from 'react-navigation';
import LoginScreen from './src/components/login/LoginScreen';
import Menu from './src/components/menu/Menu';
const App = StackNavigator({
Main: { screen: LoginScreen },
Menu: { screen: Menu }
});
export default App;
LoginScreen.js
import { StackNavigator } from 'react-navigation';
import React, { Component } from 'react';
import { StyleSheet, View, Text, Image } from 'react-native';
import LoginForm from './LoginForm';
class LoginScreen extends Component {
render() {
return (
<View style={styles.container}>
<View style={styles.logoContainer}>
<Image
style={styles.logo}
source={require('../../images/transparent.png')}
/>
<View style={{ flexDirection: 'row' }}>
<Text style={styles.blueTextStyle}>Blue</Text>
<Text style={styles.bulkTextStyle}>Bulk</Text>
</View>
</View>
<View style={styles.formContainer}>
<LoginForm />
</View>
</View>
);
}
}
export default LoginScreen;
LoginForm.js
import React, { Component } from 'react';
import {
StyleSheet,
TextInput,
TouchableOpacity,
Text,
View,
KeyboardAvoidingView,
Keyboard
} from 'react-native';
import { StackNavigator } from 'react-navigation';
class LoginForm extends Component {
render() {
return (
<KeyboardAvoidingView behavior='height' style={styles.container}>
<View style={{ flexDirection: 'row' }}>
<Text style={styles.textStyle}>Email:</Text>
<TextInput
style={styles.styleInput}
placeholder="[email protected]"
returnKeyType="next"
keyboardType="email-address"
onSubmitEditing={() => this.refs.password.focus()}
/>
</View>
<View style={{ flexDirection: 'row' }}>
<Text style={styles.textStyle}>Password:</Text>
<TextInput
ref='password'
style={styles.styleInput}
placeholder="password"
secureTextEntry
returnKeyType="go"
onSubmitEditing={Keyboard.dismiss}
/>
</View>
<TouchableOpacity
style={styles.buttonContainer}
onPress={() => this.props.navigation.navigate('Menu')} //Error here
>
<Text style={styles.buttonText}>Login</Text>
</TouchableOpacity>
</KeyboardAvoidingView>
);
}
}
export default LoginForm;
Menu.js
import React, { Component } from 'react';
import { StyleSheet, View, Text, TouchableOpacity } from 'react-native';
import { StackNavigator } from 'react-navigation';
class Menu extends Component {
render() {
const { navigate } = this.props.navigation;
return (
<View style={styles.container}>
<View style={styles.viewContainer}>
<TouchableOpacity style={styles.buttonContainer}>
<Text style={styles.buttonText}>View Products</Text>
</TouchableOpacity>
<TouchableOpacity style={styles.buttonContainer}>
<Text style={styles.buttonText}>View Discounts/Offers</Text>
</TouchableOpacity>
<TouchableOpacity style={styles.buttonContainer}>
<Text style={styles.buttonText}>View Invoice History</Text>
</TouchableOpacity>
</View>
</View>
);
}
}
export default Menu;