简单的步骤：
1.在所有项目中安装插件
1.在Xaml中添加弹出窗口

• 使用文档中提供的方法显示/隐藏弹出窗口：
• 任务PushAsync（PopupPage页面，bool animate = true）
• 任务PopAllAsync（bool animate = true）

他们还提供了一个演示，检查它：https://github.com/rotorgames/Rg.Plugins.Popup/tree/master/src/Demo

添加对库的引用，即从nuget到所有项目。
在您的Android项目中，将此Rg.Plugins.Popup.Popup.Init(this, savedInstanceState);添加到MainActivity.cs OnCreate方法中的Xamarin Forms Inits之前。
iOS项目也一样，AppDelegate.cs FinishedLaunching方法（）内

//Android
 protected override void OnCreate(Bundle savedInstanceState)
 {
    base.OnCreate(savedInstanceState);
    Rg.Plugins.Popup.Popup.Init(this, savedInstanceState);  /*Must add before the other Xamarin Inits*/
     Xamarin.Essentials.Platform.Init(this, savedInstanceState);
     Xamarin.Forms.Forms.Init(this, savedInstanceState);
 }

  //iOS
  public override bool FinishedLaunching(UIApplication app, NSDictionary options)
  {
      Rg.Plugins.Popup.Popup.Init();   /* place at the top*/
      ....
  }

在Views目录下添加新的ContentPage（.xaml）。

<?xml version="1.0" encoding="utf-8" ?>
<pages:PopupPage
  xmlns="http://xamarin.com/schemas/2014/forms"
  xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"  
  xmlns:pages="clr-namespace:Rg.Plugins.Popup.Pages;assembly=Rg.Plugins.Popup"
  xmlns:animations="clr-namespace:Rg.Plugins.Popup.Animations;     assembly=Rg.Plugins.Popup"     
x:Class="MyProjectName.Views.MyContentPageName">
<pages:PopupPage.Animation>
    <animations:ScaleAnimation 
        PositionIn="Center"
        PositionOut="Center"
        ScaleIn="1.2"
        ScaleOut="0.8"
        DurationIn="400"
        DurationOut="300"
        EasingIn="SinOut"
        EasingOut="SinIn"
        HasBackgroundAnimation="True"/>
</pages:PopupPage.Animation>
  <StackLayout HorizontalAlignment="FillAndExpand" VerticalAlignment="FillAndExpand"> 
    <!-- place your layout content here ....fx a close popup button -->
     <Button Clicked="CloseBtn_Clicked" Text="Close" />
  </StackLayout>

</pages:PopupPage>

在ContentPage（PopupPage）代码隐藏文件中，添加using Rg.Plugins.Popup.Services;，继承如下

using Rg.Plugins.Popup.Services;
using System;
using System.Threading.Tasks;
using Xamarin.Forms;

[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MyContentPageName: Rg.Plugins.Popup.Pages.PopupPage
{
     public MyContentPageName()
    {
        InitializeComponent();            
    }      

      public void OnAnimationStarted(bool isPopAnimation)
    {
        // optional code here   
    }

    public void OnAnimationFinished(bool isPopAnimation)
    {
        // optional code here   
    }   

      protected override bool OnBackButtonPressed()
    {
        // Return true if you don't want to close this popup page when a back button is pressed
        return true;
    }

    // Invoked when background is clicked
    protected override bool OnBackgroundClicked()
    {
        // Return false if you don't want to close this popup page when a background of the popup page is clicked
        return false;
    }
    
    private async void CloseBtn_Clicked(object sender, EventArgs e)
    {
        await PopupNavigation.Instance.PopAsync(true);   
    }
}

在. xaml.cs页面中，您要打开弹出窗口，添加以下内容：

using System;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
using Rg.Plugins.Popup.Contracts;
using Rg.Plugins.Popup.Services;

public partial class MyOtherPage : ContentPage
{
   private IPopupNavigation _popup { get; set; }
   private MyContentPageName _modalPage;

    public MyOtherPage()    
    {
        _popup = PopupNavigation.Instance;
        _modalPage = new MyContentPageName();
    }   

   protected override void OnAppearing()
   {
       base.OnAppearing();          
       _popup.Popped += Popup_Popped;
   }

   protected override void OnDisappearing()
   {
       base.OnDisappearing();           
       _popup.Popped -= Popup_Popped;
   }

   private async void Tapped_OpenModal(object sender, EventArgs e)
   {
       await _popup.PushAsync(_modalPage);
   }
  
   /// <summary> Triggered when the MyContentPageName popup is closed "PopAsync()" </summary>
    private async void Popup_Popped(object sender, Rg.Plugins.Popup.Events.PopupNavigationEventArgs e)
    {
        /* add your logic here, if necessary  */
    }
}

• 注意：如果你的modal只是显示静态内容，在OnAppearing（）/OnDisappearing（）中不需要_pop事件委托。**

System.InvalidOperationException：出现“平台未创建”错误