iOS和Universal WIndows App中的屏幕密度

Question

嗨,我需要知道Windows 10/8/8.1和iOS中的屏幕密度.我使用DisplayMetrics在Android中获得了屏幕密度,但我发现在UWP和iOS中没有这样的选项/属性.那么在UWP和IOS中是否有任何可以获得屏幕密度的属性.

Answer 1

更新 - 2018年6月8日

Xamarin发布了Xamarin.Essentials!

Xamarin.Essentials为开发人员提供了适用于其移动应用程序的跨平台API.

Android,iOS和UWP提供独特的操作系统和平台API,开发人员可以通过C#利用Xamarin访问所有人.Xamarin.Essentials提供了一个单一的跨平台API,可以与任何Xamarin.Forms,Android,iOS或UWP应用程序一起使用,无论用户界面如何创建,都可以从共享代码访问这些应用程序. https://github.com/xamarin/Essentials

您现在可以搜索设备的显示信息,而无需管理所有单个平台代码段.

设备显示信息 - https://docs.microsoft.com/en-us/xamarin/essentials/device-display

如何:

在您的班级中添加对Xamarin.Essentials的引用:

using Xamarin.Essentials;

以下信息通过API公开:

// 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;

有用的链接:

• (Github)Xamarin.Essentials - https://github.com/xamarin/Essentials

• (博客)Xamarin.Essentials - https://blog.xamarin.com/xamarin-essentials-cross-platform-apis-mobile-apps/

• (Docs)Essentials入门 - https://docs.microsoft.com/en-us/xamarin/essentials/get-started

原帖(Xamarin.Essentials存在之前)

下面,我将特定操作系统的屏幕详细信息存储在static位于Xamarin Forms App类中的变量中

这些似乎都适用于我的测试.

(从我的github页面复制/粘贴 - https://github.com/mattregul/Xamarin_Screensize)

Android(MainActivity.cs) - 跳转到Github页面

// Store off the device sizes, so we can access them within Xamarin Forms
// Screen Width = WidthPixels / Density
// Screen Height = HeightPixels / Density

App.DisplayScreenWidth  = (double)Resources.DisplayMetrics.WidthPixels / (double)Resources.DisplayMetrics.Density;
App.DisplayScreenHeight = (double)Resources.DisplayMetrics.HeightPixels / (double)Resources.DisplayMetrics.Density; 
App.DisplayScaleFactor  = (double)Resources.DisplayMetrics.Density;

iOS(AppDelegate.cs) - 跳转到Github页面

// 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;

注意在所有Windows示例中screensize都是根项目命名空间

UWP(App.xaml.cs) - 跳转到Github页面

// You decided which is best for you...
//  Do you want Size of the App's View
//      or
//  Do you want the Display's resolution 
// ######################################

// Size of App's view
screensize.App.DisplayScreenHeight = Windows.UI.ViewManagement.ApplicationView.GetForCurrentView().VisibleBounds.Height;
screensize.App.DisplayScreenWidth = Windows.UI.ViewManagement.ApplicationView.GetForCurrentView().VisibleBounds.Width;

// Size of screen's resolution
//screensize.App.DisplayScreenWidth = Windows.Graphics.Display.DisplayInformation.GetForCurrentView().ScreenHeightInRawPixels;
//screensize.App.DisplayScreenHeight = Windows.Graphics.Display.DisplayInformation.GetForCurrentView().ScreenWidthInRawPixels;

// Pixels per View Pixel
// - https://msdn.microsoft.com/en-us/windows/uwp/layout/design-and-ui-intro#effective-pixels-and-scaling
// - https://msdn.microsoft.com/en-us/windows/uwp/layout/screen-sizes-and-breakpoints-for-responsive-design
screensize.App.DisplayScaleFactor = Windows.Graphics.Display.DisplayInformation.GetForCurrentView().RawPixelsPerViewPixel;

Windows Phone 8.1(App.xaml.cs) - 跳转到Github页面

// Size of App's view
screensize.App.DisplayScreenHeight = Windows.UI.ViewManagement.ApplicationView.GetForCurrentView().VisibleBounds.Height;
screensize.App.DisplayScreenWidth = Windows.UI.ViewManagement.ApplicationView.GetForCurrentView().VisibleBounds.Width;

// Pixels per View Pixel
// - https://msdn.microsoft.com/en-us/windows/uwp/layout/design-and-ui-intro#effective-pixels-and-scaling
// - https://msdn.microsoft.com/en-us/windows/uwp/layout/screen-sizes-and-breakpoints-for-responsive-design
screensize.App.DisplayScaleFactor = Windows.Graphics.Display.DisplayInformation.GetForCurrentView().RawPixelsPerViewPixel;

Windows 8.1(App.xaml.cs) - 跳转到Github页面

// Size of App's view
screensize.App.DisplayScreenHeight = Window.Current.Bounds.Height;
screensize.App.DisplayScreenWidth = Window.Current.Bounds.Width;
screensize.App.DisplayScaleFactor = 1; // No scaling here?  If you find a scaling for Windows 8.1, please let me know :)

Xamarin Forms Page(App.cs) - 跳转到Github页面

namespace screensize
{
    public class App : Application
    {
        public static double DisplayScreenWidth = 0f;
        public static double DisplayScreenHeight = 0f;
        public static double DisplayScaleFactor = 0f;

        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);
        }

    }
}