小编clt*_*ang的帖子

有2类，Foo和Bar。Foo对象中嵌套了一个Bar对象。

public class Foo {
    public Guid FooId { get; set; }
    public string FooName { get; set; }
    [ForeignKey("Bar")]
    public Guid BarId { get; set; }

    public virtual Bar Bar { get; set; }
}

public class Bar {
    public Guid BarId { get; set; }
    public string BarName { get; set; }
}

public class FooBarContext : DbContext {
    public DbSet<Foo> Foos { get; set; }
    public DbSet<Bar> Bars { get; set; }
}

public class FooDTO { …

我正在使用 React Navigation 5，我希望我的选项卡栏在特定屏幕上有所不同。我尝试了很多事情，但没有成功...我希望第二个屏幕的 tabIcon 仅当活动屏幕是第二个屏幕时才可见，并且当我在同一屏幕上时更改选项卡背景颜色。这是我的代码和两张照片来展示我想做的事情。

import React from 'react';
import 'react-native-gesture-handler';
import { createMaterialTopTabNavigator } from '@react-navigation/material-top-tabs';

import Photo from './Home';
import Folders from './Folders';
import Search from './Search';

import CustomIcon from './components/CustomIcon.js';

import { Dimensions } from "react-native";

const Tab = createMaterialTopTabNavigator();

export default function TabNavigator() {
  return (
    <Tab.Navigator
    initialRouteName = 'Photo' 
    tabBarOptions= {{
        activeTintColor: '#FFCD29',
        inactiveTintColor: 'white',
        showLabel: true, //icons in label because maxsize of tabBarIcons is 25
        showIcon: false,
        indicatorStyle:{height: 0},
        pressColor: 'transparent', 
        pressOpacity: 0, …