React Native Navigation Drawer - 如何在createDrawerNavigator中启动警报

Question

我试图通过使用reactnavigation进行的navDrawer中的项目单击来触发注销（警报确认）。你知道一种有效的方法吗？

这是DrawerNavigator文件中的代码：

export default createDrawerNavigator({
    Home: { screen: Home },
    Dashboard: { screen: Dashboard },
    Logout: { screen: Logout }
} ...

当我试图调用最后一个元素（Logout）时，我知道我需要调用一个从Component类扩展的类，但问题就像下一个代码一样，在这种情况下你可以看到我在render方法中返回null，它会清除完全是屏幕，但是当试图点击进入警报按钮时，它不会给我任何东西

import React, {Component} from 'react';
import { Alert } from 'react-native';

class Logout extends Component{

constructor(props){
    console.log('those are the props '+JSON.stringify(props))
    super(props);
    this.logoutAlert();
}

logout = ()=>{
    //const deleted_element = clearAllData();
    console.log('Logout.js - Element deleted ');
}

canceledLogout = () => {
    console.log('The logout process is now cancelled');
}

logoutAlert() {
    Alert.alert(
        'Confirm',
        'Are you sure that you want to logout?',
        [
            { text: 'Yes', onPress: () => this.logout },
            { text: 'Cancel', onPress: () => this.canceledLogout }
        ]
    );
}

render(){
  return null;
}


}

export default Logout;

所以在那之后问题是：有没有办法实现它（通过单击navDrawerItem显示警报而不渲染屏幕？非常感谢你的帮助

Answer 1

我认为，您可以定义一个自定义的DrawerComponent，而不是定义一个空的Logout Screen（返回null），它可以处理诸如提醒警报和导航到不同屏幕之类的事情。

这样你的DrawerNavigator看起来就像这样 -

export const DrawerNavigator = createDrawerNavigator({
    Home: { screen: Home },
    Dashboard: { screen: Dashboard },

    ...More Screens
  }, {
    drawerOpenRoute: 'DrawerOpen',
    drawerCloseRoute: 'DrawerClose',
    drawerToggleRoute: 'DrawerToggle',
    drawerWidth: 250,
    useNativeAnimations: true,
    contentComponent: DrawerComponent
})

你可以像这样创建你的DrawerComponent -

class DrawerComponent extends React.Component {
  navigateTo = (routeName) => {
    this.props.navigation.navigate(routeName)
  }

  logout = ()=>{
    //const deleted_element = clearAllData();
    console.log('Logout.js - Element deleted ');
  }

  canceledLogout = () => {
    console.log('The logout process is now cancelled');
  }

  logoutAlert = () => {
    Alert.alert(
      'Confirm',
      'Are you sure that you want to logout?',
      [
          { text: 'Yes', onPress: () => this.logout },
          { text: 'Cancel', onPress: () => this.canceledLogout }
      ]
    );
  }

  render() {
    <ScrollView>
      <TouchableOpacity onPress={() => this.navigateTo('Home')}> Home </TouchableOpacity>
      <TouchableOpacity onPress={() => this.navigateTo('Dashboard')}> Dashboard </TouchableOpacity>
      <TouchableOpacity onPress={this.logoutAlert}> Logout </TouchableOpacity>
    </ScrollView>
  }
}

...

希望能帮助到你。