Xamarin.Forms: Not appearing OxyPlot Pie Chart

问题

Good Day everyone. I'm creating a Xamarin.Forms Portable Application and I want to display there a Chart using a OxyPlot.

I followed a documentation in here about OxyPlot. But I still kinda confuse. Can you please look at the process I followed and check if what I did was right? These are just based on my own understanding.

Here's what I did :

1. Update the Xamarin.Forms NuGet packages to the latest version.
2. Add the OxyPlot.Xamarin.Forms NuGet package in both the portable and platform specific projects.
3. I initialize the OxyPlot renderers by adding OxyPlot.Xamarin.Forms.Platform.Android.PlotViewRenderer.Init(); just after the Xamarin.Forms.Forms.Init() in my MainActivity.cs

4. In the portable app project, I added this plot view to my App.cs.

   public App()
   {
       this.MainPage = new ContentPage
       {
       Content = new PlotView
       {
       Model = new PlotModel { Title = "Hello, Forms!" },
       VerticalOptions = LayoutOptions.Fill,
       HorizontalOptions = LayoutOptions.Fill,
           },
       };
   }
   

5. In my XAML page, I added this namespace declaration :

xmlns:oxy="clr-namespace:OxyPlot.Xamarin.Forms;assembly=OxyPlot.Xamarin.Forms"

6. Then I added this on the same page.

    <oxy:PlotView Model="{Binding Model1}" VerticalOptions="Center" HorizontalOptions="Center" />
   

   Here's the code of the whole SalesPage.xaml

   <?xml version="1.0" encoding="utf-8" ?>
   <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
        xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
        xmlns:oxy="clr-namespace:OxyPlot.Xamarin.Forms;assembly=OxyPlot.Xamarin.Forms"
        xmlns:ViewModels="clr-namespace:XamarinFormsDemo.ViewModels;assembly=XamarinFormsDemo"
        x:Class="XamarinFormsDemo.Views.SalesPage"
        BackgroundImage="bg3.jpg"
        Title="Sales Page">
   
   
   
     <ContentPage.BindingContext>
       <ViewModels:SalesVM/>
     </ContentPage.BindingContext>
   
   
       <oxy:PlotView Model="{Binding Model1}" VerticalOptions="Center" HorizontalOptions="Center"/>
   
   
   </ContentPage>
   

7. After that, I tried to call my view model that contains the content of my chart named PiewViewModel.cs

   using OxyPlot;
   using OxyPlot.Series;
   
   namespace ExampleLibrary
   {
   
       public class PieViewModel
       {
           private PlotModel modelP1;
           public PieViewModel()
       {
           modelP1 = new PlotModel { Title = "Pie Sample1" };
   
           dynamic seriesP1 = new PieSeries { StrokeThickness = 2.0,     InsideLabelPosition = 0.8, AngleSpan = 360, StartAngle = 0 };
   
           seriesP1.Slices.Add(new PieSlice("Africa", 1030) { IsExploded = false, Fill = OxyColors.PaleVioletRed });
           seriesP1.Slices.Add(new PieSlice("Americas", 929) { IsExploded = true });
           seriesP1.Slices.Add(new PieSlice("Asia", 4157) { IsExploded = true });
           seriesP1.Slices.Add(new PieSlice("Europe", 739) { IsExploded = true });
           seriesP1.Slices.Add(new PieSlice("Oceania", 35) { IsExploded = true });
   
           modelP1.Series.Add(seriesP1);
   
       }
   
       public PlotModel Model1
       {
           get { return modelP1; }
           set { modelP1 = value; }
       }
      }
    }
   

8. Here's my MainActivity.cs for Android

     using System;
     using Android.App;
     using Android.Content.PM;
     using Android.Runtime;
     using Android.Views;
     using Android.Widget;
     using Android.OS;
     using ImageCircle.Forms.Plugin.Droid;
   
     namespace XamarinFormsDemo.Droid
     {
         [Activity(Label = "XamarinFormsDemo", Icon = "@drawable/recordsicon", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
         public class MainActivity :           global::Xamarin.Forms.Platform.Android.FormsApplicationActivity
         {
             protected override void OnCreate(Bundle bundle)
   {
       base.OnCreate(bundle);
   
       global::Xamarin.Forms.Forms.Init(this, bundle);
       OxyPlot.Xamarin.Forms.Platform.Android.PlotViewRenderer.Init();
       LoadApplication(new App());
       ImageCircleRenderer.Init();
             }
         }
     }
   

Can you please tell me what I've done wrong? The chart isn't appearing. Any help to a newbie like me is highly appreciated. Thanks a lot.

回答1:

Your MainActivity class needs to derive from AndroidActivity not FormsApplicationActivity

来源：https://stackoverflow.com/questions/38517748/xamarin-forms-not-appearing-oxyplot-pie-chart