Tabbed-Seite In Master-Detail-Seite Xamarin

Ich versuche, fügen Sie ein Registerkarten-Seite wie gezeigt, in der xamarin-Dokumentation, aber ich bekomme immer folgenden Fehler, System.NullReferenceException "Objektverweis nicht auf eine Instanz eines Objekts." Brauche ich zu erklären, ein neues Objekt für jede Seite, oder ist dies geschieht automatisch, wenn Sie mit xaml?

Hier ist mein StackTrace,

  at Xamarin.Forms.Platform.Android.AppCompat.Platform.LayoutRootPage(Xamarin.Forms.P age page, Int32 width, Int32 height) [0x0005d] in   C:\BuildAgent\work\aad494dc9bc9783\Xamarin.Forms.Platform.Android\AppCompat\Plat form.cs:279 
  at Xamarin.Forms.Platform.Android.AppCompat.Platform.Xamarin.Forms.Platform.Android.IPlatformLayout.OnLayout (Boolean changed, Int32 l, Int32 t, Int32 r, Int32 b) [0x00003] in C:\BuildAgent\work\aad494dc9bc9783\Xamarin.Forms.Platform.Android\AppCompat\Platform.cs:196 
  at Xamarin.Forms.Platform.Android.PlatformRenderer.OnLayout (Boolean changed, Int32 l, Int32 t, Int32 r, Int32 b) [0x0000e] in C:\BuildAgent\work\aad494dc9bc9783\Xamarin.Forms.Platform.Android\PlatformRenderer.cs:73 
  at Android.Views.ViewGroup.n_OnLayout_ZIIII (IntPtr jnienv, IntPtr native__this, Boolean changed, Int32 l, Int32 t, Int32 r, Int32 b) [0x00009] in /Users/builder/data/lanes/3415/7db2aac3/source/monodroid/src/Mono.Android/platforms/android-23/src/generated/Android.Views.ViewGroup.cs:3427 
  at (wrapper dynamic-method) System.Object:d59f31f1-b9b6-40ea-9254-a422fe409750 (intptr,intptr,bool,int,int,int,int)

Hier ist mein code,

using Xamarin.Forms;
namespace BSi.Mobile.Events.Views
{
    public partial class MainMasterDetailPage : MasterDetailPage
    {
        public MainMasterDetailPage()
        {
            InitializeComponent();
        }
    }
}

<?xml version="1.0" encoding="utf-8" ?>
<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms"
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
              xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms"
              xmlns:local="clr-namespace:BSi.Mobile.Events.Views;assembly=BSi.Mobile.Events"
              prism:ViewModelLocator.AutowireViewModel="True"
              x:Class="BSi.Mobile.Events.Views.MainMasterDetailPage">
    <MasterDetailPage.Master>
       <ContentPage Title="Default" Padding="10">
          <StackLayout>
             <Button Text="Home" Command="{Binding MenuSelectedCommand}"  CommandParameter="NavigationPage\MainPage"/>
             <Button Text="Event Schedule" Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage\EventPage"/>
             <Button Text="Floor Plan" Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage\FloorPlanPage"/>
             <Button Text="Sponsor/Media Partners" Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage\SponsorsPage"/>
             <Button Text="Where To Eat" Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage\FoodNearbyPage"/>
          </StackLayout>
       </ContentPage>
   </MasterDetailPage.Master>
   <MasterDetailPage.Detail>
       <TabbedPage>
           <TabbedPage.Children>
              <local:MainPage Title="Info" Icon="http://icons.iconarchive.com/icons/graphicloads/100-flat/256/home-icon.png"/>
              <local:EventPage Title="Sessions" Icon="http://icons.iconarchive.com/icons/graphicloads/100-flat/256/home-icon.png"/>
              <local:SpeakersPage Title="Speakers" Icon="http://icons.iconarchive.com/icons/graphicloads/100-flat/256/home-icon.png"/>
              <local:ExhibitsPage Title="Exhibits" Icon="http://icons.iconarchive.com/icons/graphicloads/100-flat/256/home-icon.png"/>
           </TabbedPage.Children>
       </TabbedPage>
   </MasterDetailPage.Detail>
</MasterDetailPage>

UPDATE:

Ich einige änderungen vorgenommen, wie vorgeschlagen, durch SushiHangover, die ich jetzt erhalte keinen Fehler, aber mein tabbed-Menü nicht erscheint.

InformationsquelleAutor Jamie Steele | 2016-07-29

Können Sie hinzufügen TabbedPage Kinder, wie dies in XAML:

<MasterDetailPage.Detail>
    <TabbedPage>
        <TabbedPage.Children>
            <ContentPage Title="Page 1" Icon="ja.png" />
            <ContentPage Title="Page 2" Icon="ja.png" />
            <ContentPage Title="Page 3" Icon="ja.png" />
        </TabbedPage.Children>
    </TabbedPage>
</MasterDetailPage.Detail>

Ersetzen Sie einfach Ihre "lokalen" benutzerdefinierte Seiten für ContentPage

Oder per code:

public TabsPage ()
{
    this.Children.Add (new ContentPage () { Title = "Page 1", Icon = "ja.png" });
    this.Children.Add (new ContentPage () { Title = "Page 2", Icon = "ja.png" });
    this.Children.Add (new ContentPage () { Title = "Page 3", Icon = "ja.png" });
}

Ich habe die änderungen, die Sie vorgeschlagen, jetzt bekomme ich keine Fehler aber das Menü nicht erscheint?

InformationsquelleAutor SushiHangover

Die Antwort war der Einsatz von Befehls-parameter, der relativ zu den Seiten, die angezeigt werden, die tabbed-Seite.

<?xml version="1.0" encoding="utf-8"?>
<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms"
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
              xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms"
              prism:ViewModelLocator.AutowireViewModel="True"
              x:Class="BSi.Mobile.Events.Views.MainMasterDetailPage">
<MasterDetailPage.Master>
   <ContentPage Title="Default">
     <StackLayout>
       <StackLayout BackgroundColor="{StaticResource iconGray}" Padding="15"      HeightRequest="100">
         <Image Source="canfitpro_logo2" HeightRequest="60" HorizontalOptions="Start" VerticalOptions="EndAndExpand" />
       </StackLayout>
       <TableView Intent="Form" HasUnevenRows="True">
         <TableRoot>
           <TableSection Title="Vancouver Fitness Expo">
             <ViewCell>
              <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal">
                 <StackLayout.GestureRecognizers>
                   <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="EventTabbedPage/NavigationPage/MainPage"/>
                 </StackLayout.GestureRecognizers>
                 <Image Source="icon_home_circle" HeightRequest="40"/>
                 <Label Text="Home" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/>
               </StackLayout>
             </ViewCell>
             <ViewCell>
               <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal">
                 <StackLayout.GestureRecognizers>
                   <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="EventTabbedPage/NavigationEventPage"/>
                 </StackLayout.GestureRecognizers>
                 <Image Source="icon_sessions_circle" HeightRequest="40"/>
                 <Label Text="Sessions" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/>
               </StackLayout>
             </ViewCell>
           </TableSection>
           <TableSection Title="Resources">
             <ViewCell>
               <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal">
                 <StackLayout.GestureRecognizers>
                   <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage/FloorPlanPage"/>
                 </StackLayout.GestureRecognizers>
                 <Image Source="icon_floormap_circle" HeightRequest="40"/>
                 <Label Text="Floor Plan" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/>
               </StackLayout>
             </ViewCell>
             <ViewCell>
               <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal">
                 <StackLayout.GestureRecognizers>
                   <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage/SponsorsPage"/>
                 </StackLayout.GestureRecognizers>
                 <Image Source="icon_partners_circle" HeightRequest="40"/>
                 <Label Text="Sponsor /Media Partners" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/>
               </StackLayout>
             </ViewCell>
             <ViewCell>
               <StackLayout Margin="15, 10, 10, 10" Orientation="Horizontal">
                 <StackLayout.GestureRecognizers>
                   <TapGestureRecognizer Command="{Binding MenuSelectedCommand}" CommandParameter="NavigationPage/FoodNearbyPage"/>
                 </StackLayout.GestureRecognizers>
                 <Image Source="icon_restaurant_circle" HeightRequest="40"/>
                 <Label Text="Where To Eat" VerticalTextAlignment="Center" Margin="20, 0, 0, 0" Style="{DynamicResource SubtitleStyle}"/>
               </StackLayout>
             </ViewCell>
           </TableSection>
         </TableRoot>        
       </TableView>        
     </StackLayout>
   </ContentPage>
  </MasterDetailPage.Master>
</MasterDetailPage>

InformationsquelleAutor Jamie Steele

Schreibe einen Kommentar

Du musst angemeldet sein, um einen Kommentar abzugeben.