Question

我正在尝试通过使用reactnavigation制作的navDrawer中的项目单击触发注销（确认警报）。您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 }
} ...

当尝试调用最后一个元素（注销）时，我知道我需要调用一个从Component类扩展的类，但是问题类似于下一个代码，在这种情况下，如您所见，我在render方法中返回了null ，它会完全清除屏幕，但是当尝试单击警报按钮时，它什么也没给我

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，在那之后的问题是：有没有办法做到这一点（通过单击navDrawerItem而不显示屏幕来显示警报？非常感谢您的帮助

Answer 1

我认为可以定义一个自定义的DrawerComponent来处理提示 Alerts 和 Navigation 之类的内容，而不是定义一个空的注销屏幕（返回空值）。到不同的屏幕。

这样做，您的DrawerNavigator看起来会与此类似-

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

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

您可以这样创建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>
  }
}

...

希望有帮助。

React Native NavigationDrawer-如何在createDrawerNavigation

1 个答案: