使用xamarin PCL &棱鏡圖書館InitializeComponent();在棱鏡庫中不存在?
public class App : PrismApplication
{
public App(IPlatformInitializer initializer = null) : base(initializer)
{ }
protected override void OnInitialized()
{
//InitializeComponent();
NavigationService.NavigateAsync("MainPage");
}
protected override void RegisterTypes()
{
Container.RegisterTypeForNavigation<MainPage>("MainPage");
Container.RegisterTypeForNavigation<LoginPage>("LoginPage");
Container.RegisterTypeForNavigation<ServicePage>("ServicePage");
}
}
形式MainActivity.cs
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsApplicationActivity
{
protected override void OnCreate(Bundle bundle)
{
//TabLayoutResource = Resource.Layout.Tabbar;
//ToolbarResource = Resource.Layout.Toolbar;
base.OnCreate(bundle);
global::Xamarin.Forms.Forms.Init(this, bundle);
LoadApplication(new App(new AndroidInitializer()));
}
public class AndroidInitializer : IPlatformInitializer
{
public void RegisterTypes(IUnityContainer container)
{
}
}
主要Page.cs
namespace PRProject.Views
{
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
BackgroundImage = "Background.png";
}
}
和MainPage.xaml中
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="PRProject.Views.MainPage" BackgroundImage="Background.png"
xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms"
prism:ViewModelLocator.AutowireViewModel="True">
<StackLayout VerticalOptions="End" HorizontalOptions="Center" Orientation="Vertical" Margin="20,0,20,10">
<ScrollView VerticalOptions="FillAndExpand" Orientation="Vertical" HorizontalOptions="Center">
<StackLayout>
<StackLayout VerticalOptions="End" HorizontalOptions="Center" Orientation="Horizontal" Margin="0,0,0,20">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Image Grid.Column="1" Source="signin.png">
<Image.GestureRecognizers>
<TapGestureRecognizer Command="{Binding NavigateCommand}" />
</Image.GestureRecognizers>
</Image>
</Grid>
</StackLayout>
</StackLayout>
</ScrollView>
</StackLayout>
</ContentPage>
和視圖模型
namespace PRProject.ViewModels
{
public class MainPageViewModel : BindableBase, INavigationAware
{
private INavigationService _navigationService;
public DelegateCommand NavigateCommand { get; set; }
public MainPageViewModel(INavigationService navigationService)
{
_navigationService = navigationService;
NavigateCommand = new DelegateCommand(Navigate);
}
private void Navigate()
{
_navigationService.NavigateAsync("LoginPage");
}
}}
- 問題是
- 我沒有InitializeCompenent()被調用內部OnInitialized()
- 當導航到網主頁它顯示爲空白頁
- 主活動中的另一個額外問題如果主活動類繼承自 global :: Xamarin.Forms.Platform.Android.FormsAppCompatActivity它將返回null異常
- 裏面主要活動Registertype的參數是IContainer,但對我來說它是IUnityContainer。
我刪除了滾動視圖,並且主頁也是空白的,但一段時間後它返回(System.InvalidOperationException:Sequence不包含任何元素)異常 –
只需在MainPage中使用'Label'即可排除其他任何問題。 MainPage構造函數是否被調用? –
yes MainPage構造函數調用成功,沒有問題或異常,但頁面仍然爲空。 –