Myujth

I need to get DPI device in my Xamarin class PCL. I do not want to use Xamarin.Essentials. Can I do this using Native interfaces, if its possible, how can I do it?

in your pcl create a new interface called IDisplayInfo:

public interface IDisplayInfo

 int GetDisplayWidth();
 int GetDisplayHeight();
 int GetDisplayDpi();

In your android implementation, add a new class:

[assembly: Dependency(typeof(DisplayInfo))]
namespace YourAppNamespace.Droid

 public class DisplayInfo : IDisplayInfo
 
 public int GetDisplayWidth()
 
 return (int)Android.App.Application.Context.Resources.DisplayMetrics.WidthPixels;
 

 public int GetDisplayHeight()
 
 return (int)Android.App.Application.Context.Resources.DisplayMetrics.HeightPixels;
 

 public int GetDisplayDpi()
 
 return (int)Android.App.Application.Context.Resources.DisplayMetrics.DensityDpi;
 
 

and in the iOS implementation, add the same class:

[assembly: Dependency(typeof(DisplayInfo))] 
namespace YourNamespace.iOS

 public class DisplayInfo : IDisplayInfo
 
 public int GetDisplayWidth()
 
 return (int)UIScreen.MainScreen.Bounds.Width;
 

 public int GetDisplayHeight()
 
 return (int)UIScreen.MainScreen.Bounds.Height;
 

 public int GetDisplayDpi()
 
 return (int)(int)UIScreen.MainScreen.Scale;
 
 

Now in your shared code, you can call

int dpi = DependencyService.Get<IDisplayInfo>().GetDisplayDpi();

and should be good to go. Note that i also added methods for getting screen width and height, basically because i already had them in my code and since you are probably going to need them sooner or later anyways.

I have a static class Core to store some shared stuff defined the shared code.
On app start it's receiving values for later use everywhere:

Android MainActivity OnCreate:

 Core.IsAndroid = true;
 Core.DisplayDensity = Resources.DisplayMetrics.Density;

iOS AppDelegate FinishedLaunching:

 Core.IsIOS = true;
 Core.DisplayDensity = (float)(UIScreen.MainScreen.NativeBounds.Width / UIScreen.MainScreen.Bounds.Width);