How wide is the master page of a Master-Detail Page in Xamarin.Forms? - layout

Question

Depending on the screen size (and device idiom?) the width of the master page varies: On phones it is about 80 % of the screen width, while on tablets it seems to be a constant dimension like 320 dp.
Does anybody know a general formula for this value? I'd like to use it for laying out some elements during construction time, when the Width property isn't set, yet.
Edit:
I know how to get the current screen size. But how does the width of the presented master page of Xamarin.Form's master-detail page relate to it? It doesn't cover the whole screen, but fills a different fraction of it depending on the device.

Answer 1

You could request the device's actual screen width, height, and scale factor.
(From https://github.com/mattregul/Xamarin_GetDeviceScreensize)
iOS AppDelegate.cs
[Register("AppDelegate")]
public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate
{
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
global::Xamarin.Forms.Forms.Init();
// Store off the device sizes, so we can access them within Xamarin Forms
App.DisplayScreenWidth = (double)UIScreen.MainScreen.Bounds.Width;
App.DisplayScreenHeight = (double)UIScreen.MainScreen.Bounds.Height;
App.DisplayScaleFactor = (double)UIScreen.MainScreen.Scale;
LoadApplication(new App());
return base.FinishedLaunching(app, options);
}
}
Android MainActivity.cs
[Activity(Label = "Xamarin_GetDeviceScreensize.Droid", Icon = "#drawable/icon", Theme = "#style/MyTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
protected override void OnCreate(Bundle bundle)
{
TabLayoutResource = Resource.Layout.Tabbar;
ToolbarResource = Resource.Layout.Toolbar;
base.OnCreate(bundle);
// Store off the device sizes, so we can access them within Xamarin Forms
App.DisplayScreenWidth = (double)Resources.DisplayMetrics.WidthPixels / (double)Resources.DisplayMetrics.Density; // Width = WidthPixels / Density
App.DisplayScreenHeight = (double)Resources.DisplayMetrics.HeightPixels / (double)Resources.DisplayMetrics.Density; // Height = HeightPixels / Density
App.DisplayScaleFactor = (double)Resources.DisplayMetrics.Density;
global::Xamarin.Forms.Forms.Init(this, bundle);
LoadApplication(new App());
}
}
Xamarin Forms App.cs
public class App : Application
{
public static double DisplayScreenWidth;
public static double DisplayScreenHeight;
public static double DisplayScaleFactor;
public App()
{
string ScreenDetails = Device.OS.ToString() + " Device Screen Size:\n" +
$"Width: {DisplayScreenWidth}\n" +
$"Height: {DisplayScreenHeight}\n" +
$"Scale Factor: {DisplayScaleFactor}";
// The root page of your application
var content = new ContentPage
{
Title = "Xamarin_GetDeviceScreensize",
Content = new StackLayout
{
VerticalOptions = LayoutOptions.Center,
Children = {
new Label {
HorizontalTextAlignment = TextAlignment.Center,
FontSize = Device.GetNamedSize (NamedSize.Large, typeof(Label)),
Text = ScreenDetails
}
}
}
};
MainPage = new NavigationPage(content);
}
}