Xamarin.Essentials:地理編碼
地理編碼類別會提供 API,可以將地標進行地理編碼為位置座標,也可以將地理編碼座標反轉為地標。
若要開始使用此 API,請閱讀 入門指南Xamarin.Essentials,以確保連結庫已正確安裝並設定在您的專案中。
若要存取地理編碼功能,需要下列平台特定設定。
在類別中新增 的 Xamarin.Essentials 參考:
C#
using Xamarin.Essentials;
取得地址的位置座標:
C#
try
{
var address = "Microsoft Building 25 Redmond WA USA";
var locations = await Geocoding.GetLocationsAsync(address);
var location = locations?.FirstOrDefault();
if (location != null)
{
Console.WriteLine($"Latitude: {location.Latitude}, Longitude: {location.Longitude}, Altitude: {location.Altitude}");
}
}
catch (FeatureNotSupportedException fnsEx)
{
// Feature not supported on device
}
catch (Exception ex)
{
// Handle exception that may have occurred in geocoding
}
高度不一定可用。 如果不可用,則 Altitude
屬性可能為 null
,或值可能為零。 如可使用高度,此值 (公尺) 會高於海平面。
反向地理編碼是為一組現有座標集取得地標的流程:
C#
try
{
var lat = 47.673988;
var lon = -122.121513;
var placemarks = await Geocoding.GetPlacemarksAsync(lat, lon);
var placemark = placemarks?.FirstOrDefault();
if (placemark != null)
{
var geocodeAddress =
$"AdminArea: {placemark.AdminArea}\n" +
$"CountryCode: {placemark.CountryCode}\n" +
$"CountryName: {placemark.CountryName}\n" +
$"FeatureName: {placemark.FeatureName}\n" +
$"Locality: {placemark.Locality}\n" +
$"PostalCode: {placemark.PostalCode}\n" +
$"SubAdminArea: {placemark.SubAdminArea}\n" +
$"SubLocality: {placemark.SubLocality}\n" +
$"SubThoroughfare: {placemark.SubThoroughfare}\n" +
$"Thoroughfare: {placemark.Thoroughfare}\n";
Console.WriteLine(geocodeAddress);
}
}
catch (FeatureNotSupportedException fnsEx)
{
// Feature not supported on device
}
catch (Exception ex)
{
// Handle exception that may have occurred in geocoding
}
Location
和 LocationExtensions
類別會定義方法,以計算兩個位置之間的距離。 如需範例,請參閱文章Xamarin.Essentials:地理位置。