使用Xamarin表单为安卓和iOS创建底部导航栏

<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
            xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
            xmlns:views="clr-namespace:YourAppName.Views"
            x:Class="YourAppName.MainPage">

    <TabbedPage.Children>
        <NavigationPage Title="首页">
            <x:Arguments>
                <views:HomePage />
            </x:Arguments>
        </NavigationPage>

        <NavigationPage Title="消息">
            <x:Arguments>
                <views:MessagePage />
            </x:Arguments>
        </NavigationPage>

        <NavigationPage Title="设置">
            <x:Arguments>
                <views:SettingsPage />
            </x:Arguments>
        </NavigationPage>
    </TabbedPage.Children>

</TabbedPage>

namespace YourAppName.Views
{
    public partial class HomePage : ContentPage
    {
        public HomePage()
        {
            InitializeComponent();
        }
    }
}

// 同样的方式创建MessagePage和SettingsPage

public App()
{
    InitializeComponent();

    MainPage = new MainPage();
}