How to get DPI device to PCL in Xamarin. Forms? - xamarin

Question

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?

Answer 1

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.

Answer 2

Currently Device Display Information available via official Xamarin.Essentials nuget package, see:
https://learn.microsoft.com/en-us/xamarin/essentials/device-display
// Get Metrics
var mainDisplayInfo = DeviceDisplay.MainDisplayInfo;
// Orientation (Landscape, Portrait, Square, Unknown)
var orientation = mainDisplayInfo.Orientation;
// Rotation (0, 90, 180, 270)
var rotation = mainDisplayInfo.Rotation;
// Width (in pixels)
var width = mainDisplayInfo.Width;
// Height (in pixels)
var height = mainDisplayInfo.Height;
// Screen density
var density = mainDisplayInfo.Density;

Answer 3

I think it will help you. Here you have it described
enter link description here

Answer 4

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);