HelloGeoLocator.cs

using System;
using System.Diagnostics;
using Plugin.Geolocator;
using Xamarin.Forms;

namespace HelloGeoLocator
{
	public class App : Application
	{


		Label locationLabel = new Label
		{
			Text = "緯度 = 0, 軽度 = 0",
			HorizontalTextAlignment = TextAlignment.Center
		};

		public App()
		{
			// The root page of your application
			var content = new ContentPage
			{
				Title = "HelloGeoLocator",
				Content = new StackLayout
				{
					VerticalOptions = LayoutOptions.Center,
					Children = {
						new Label {
							HorizontalTextAlignment = TextAlignment.Center,
							Text = "位置情報"
						},
						locationLabel // 緯度、軽度お表示
					}
				}
			};
			MainPage = new NavigationPage(content);
		}

		protected override void OnStart()
		{
			// Handle when your app starts
			updatePosition();
			// 位置情報取得時に変化が生じた場合に情報を更新する
			var locator = CrossGeolocator.Current;
			locator.PositionChanged += (sender, e) =>
			{
				updatePosition();
			};

		}

		public async void updatePosition()
		{
			try
			{
				var locator = CrossGeolocator.Current;
				var position = await locator.GetPositionAsync(timeoutMilliseconds: 10000);
				locationLabel.Text = string.Format(
					"緯度 = {0},\n 軽度 = {1} ",
					position.Latitude, position.Longitude);
			}
			catch (Exception ex)
			{
				locationLabel.Text = "取得できませんでした。";
				Debug.WriteLine(ex.Message);
			}
		}

		protected override void OnSleep()
		{
			// Handle when your app sleeps
		}

		protected override void OnResume()
		{
			// Handle when your app resumes
		}
	}
}