如何在Xamarin.phs跨平台上设置ContentPage方向或屏幕方向

Question

如何在Xamarin.Forms跨平台的特定页面上设置内容页面方向或屏幕方向。

我已设置ScreenOrientation = ScreenOrientation。

肖像属性的所有平台，但我想显示一些页面显示在两个变化意味着肖像和风景，所以如何在`xamarin.forms页面上设置。

设置屏幕方向而不是设备明智的，但在设置页面明智的某些页面显示景观&一些页面纵向显示在xamarin形式的跨平台

Answer 1

这就是我如何做到这一点在Android中。您必须将代码添加到MainActivity.cs

[Activity(...., ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]

或您的应用程序，如果用户打开他的设备会抛出异常。

然后补充一点：

//To check if device is allowed to rotate 
private bool _allowLandscape; 

public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsApplicationActivity 
{ 
    private bool _allowLandscape; 

    protected override void OnCreate(Bundle bundle) 
    { 
     switch (Device.Idiom) 
     { 
      case TargetIdiom.Phone: 
       RequestedOrientation = ScreenOrientation.Portrait; 
       break; 
      case TargetIdiom.Tablet: 
       RequestedOrientation = ScreenOrientation.Landscape; 
       break; 
     } 

     base.OnCreate(bundle); 

     //Setup additional stuff that you need 

     //Calls from the view that should rotate 
     MessagingCenter.Subscribe<GraphicsView>(this, "graphic", sender => 
     { 
      _allowLandscape = true; 
      OnConfigurationChanged(new Configuration()); 
     }); 

     //When the page is closed this is called 
     MessagingCenter.Subscribe<GraphicsView>(this, "return", sender => 
     { 
      _allowLandscape = false; 
      OnConfigurationChanged(new Configuration()); 
     }); 

     LoadApplication(new App()); 
    } 

    public override void OnConfigurationChanged(Configuration newConfig) 
    { 
     base.OnConfigurationChanged(newConfig); 

     switch (newConfig.Orientation) 
     { 
      case Orientation.Landscape: 
       switch (Device.Idiom) 
       { 
        case TargetIdiom.Phone: 
         if (!_allowLandscape) 
         { 
          LockRotation(Orientation.Portrait); 
         } 
         break; 
        case TargetIdiom.Tablet: 
         LockRotation(Orientation.Landscape); 
         break; 
       } 
       break; 
      case Orientation.Portrait: 
       switch (Device.Idiom) 
       { 
        case TargetIdiom.Phone: 
         if (!_allowLandscape) 
         { 
          LockRotation(Orientation.Portrait); 
         } 
         break; 
        case TargetIdiom.Tablet: 
         LockRotation(Orientation.Landscape); 
         break; 
       } 
       break; 
      case Orientation.Undefined: 
       if (Device.Idiom == TargetIdiom.Phone && _allowLandscape) 
       { 
        LockRotation(Orientation.Landscape); 
       } 
       else if (Device.Idiom == TargetIdiom.Phone && !_allowLandscape) 
       { 
        LockRotation(Orientation.Portrait); 
       } 
       break; 
     } 
    } 

    private void LockRotation(Orientation orientation) 
    { 
     switch (orientation) 
     { 
      case Orientation.Portrait: 
       RequestedOrientation = ScreenOrientation.Portrait; 
       break; 
      case Orientation.Landscape: 
       RequestedOrientation = ScreenOrientation.Landscape; 
       break; 
     } 
    } 
} 

希望这会为你工作。

Answer 2

您可以通过为特定平台使用DependencyService创建依赖项来实现此目的。

试着这样做：

接口

public interface IOrientationService 
    { 
     void Landscape(); 
     void Portrait(); 
    } 

对于安卓

[assembly: Xamarin.Forms.Dependency(typeof(OrientationService))] 
namespace Orientation 
{ 
    public class OrientationService: IOrientationService 
    { 
     public void Landscape() 
     { 
      ((Activity)Forms.Context).RequestedOrientation = ScreenOrientation.Landscape; 
     } 

     public void portrait() 
     { 
      ((Activity)Forms.Context).RequestedOrientation = ScreenOrientation.Portrait; 
     } 
    } 
} 

对于iOS：

[assembly: Xamarin.Forms.Dependency(typeof(OrientationService))] 
namespace Orientation 
{ 
    public class OrientationService: IOrientationService 
    { 
     public void Landscape() 
     { 
      UIDevice.CurrentDevice.SetValueForKey(new NSNumber((int)UIInterfaceOrientation.LandscapeLeft), new NSString("orientation")); 
     } 

     public void Portrait() 
     { 
      UIDevice.CurrentDevice.SetValueForKey(new NSNumber((int)UIInterfaceOrientation.Portrait), new NSString("orientation")); 
     } 
    } 
} 

然后你可以使用它像这样

DependencyService.Get<IOrientationService>().Landscape(); 
DependencyService.Get<IOrientationService>().Portrait(); 

希望它有帮助！