如何在IOS的xamarin.forms中将单个ContentPage的方向从纵向更改为全部（横向/纵向）。

Question

I want to change the orientation of the single page. My whole application should be run in portrait but I want to make one page as Landscape/portrait (both).

I have taken reference from below links

http://www.appliedcodelog.com/2017/05/force-landscape-or-portrait-for-single.html

Code is working fine in Android but not in IOS.

AppDelegate.cs

public override UIInterfaceOrientationMask GetSupportedInterfaceOrientations(UIApplication application, [Transient] UIWindow forWindow)
{
    var mainPage = Xamarin.Forms.Application.Current.MainPage;

    if (mainPage is CartoonDetail_demo2 ||
            (mainPage is NavigationPage && ((NavigationPage)mainPage).CurrentPage is CartoonDetail_demo2) ||
            (mainPage.Navigation != null && mainPage.Navigation.NavigationStack.LastOrDefault() is CartoonDetail_demo2))
    {
        return UIInterfaceOrientationMask.All;
    }

    return UIInterfaceOrientationMask.Portrait;
}

But this condition is never going to be true in any case. Eventually I can not get the page from navigation stack.

So, I use easy way to do the same thing,

I want to make "CartoonDetail_demo2" this page as Landscape/Portrait.

1. In OnAppearing() method of the "CartoonDetail_demo2" page I have set one flag as true.

2. And OnDisappering() method of the "CartoonDetail_demo2" page I have set one flag as false.

3. use this flag in AppDelegate.cs.

 public override UIInterfaceOrientationMask GetSupportedInterfaceOrientations(UIApplication application, [Transient] UIWindow forWindow) { if (AppConstants.IsOrientationAll) { return UIInterfaceOrientationMask.All; } return UIInterfaceOrientationMask.Portrait; } 

Now, Condition become true whenever I go to the page "CartoonDetail_demo2".

But It is not working and my page is always in Portrait Orientation .

4. When I simply call this method without any condition then whole application is going in "All" (Landscape/Portrait) orientation.

   public override UIInterfaceOrientationMask GetSupportedInterfaceOrientations(UIApplication application, [Transient] UIWindow forWindow) { return UIInterfaceOrientationMask.All; }

5. By default, My whole application in Portrait Orientation.

I have also tried few other demo but none of are going to working

https://xamarindevelopervietnam.wordpress.com/2017/05/23/how-to-rotate-specific-page-in-xamarin-forms/

should I use the plugin Plugin.DeviceOrientation?

Answer 1

in AppDelegate.cs

public bool allowRotation; 

And rewrite the method

public override UIInterfaceOrientationMask GetSupportedInterfaceOrientations(UIApplication application, [Transient] UIWindow forWindow)
{
   if(allowRotation==true)
   {
    return UIInterfaceOrientationMask.Landscape;
   }

   else
   {
    return UIInterfaceOrientationMask.Portrait;
   }
} 

Then you can call the following method in dependency service

in iOS

public class OrientationService : IOrientationService
{
    public void Landscape()
    {
        AppDelegate appDelegate = (AppDelegate)UIApplication.SharedApplication.Delegate;
        appDelegate.allowRotation = true;

        UIDevice.CurrentDevice.SetValueForKey(new NSNumber((int)UIInterfaceOrientation.LandscapeLeft), new NSString("orientation"));   
    }

    public void Portrait()
    {
        AppDelegate appDelegate = (AppDelegate)UIApplication.SharedApplication.Delegate;
        appDelegate.allowRotation = true;

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

in Android

public class OrientationService : IOrientationService
{
    public void Landscape()
    {
        ((Activity)Forms.Context).RequestedOrientation = ScreenOrientation.Landscape;
    }

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

For more detail you can refer this similar issue .