Xamarin Forms 自定义地图图钉
问题描述 投票：0回答：2
在我正在开发的应用程序之一中，我需要使用自定义地图图钉，并且我已按照 Xamarin 上的指南进行操作 https://developer.xamarin.com/guides/xamarin-forms/application-fundamentals/custom -renderer/map/customized-pin/ 以及借用了他们的示例代码来尝试制作我自己的示例。
它在一定程度上起作用，信息窗口实际上更新为自定义布局，但地图图钉永远不会改变。
我的自定义地图渲染器：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using Android.Content;
using Android.Gms.Maps;
using Android.Gms.Maps.Model;
using Android.Widget;
using Xamarin.Forms;
using Xamarin.Forms.Maps;
using Xamarin.Forms.Maps.Android;
using WorkingWithMaps.Droid.Renderers;
using WorkingWithMaps;
[assembly: ExportRenderer(typeof(CustomMap), typeof(CustomMapRenderer))]
namespace WorkingWithMaps.Droid.Renderers
{
public class CustomMapRenderer : MapRenderer, GoogleMap.IInfoWindowAdapter, IOnMapReadyCallback
{
GoogleMap map;
List<CustomPin> customPins;
bool isDrawn;
protected override void OnElementChanged(Xamarin.Forms.Platform.Android.ElementChangedEventArgs<Map> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
map.InfoWindowClick -= OnInfoWindowClick;
}
if (e.NewElement != null)
{
var formsMap = (CustomMap)e.NewElement;
customPins = formsMap.CustomPins;
((MapView)Control).GetMapAsync(this);
}
}
void IOnMapReadyCallback.OnMapReady(GoogleMap googleMap)
{
map = googleMap;
map.SetInfoWindowAdapter(this);
map.InfoWindowClick += OnInfoWindowClick;
this.NativeMap = googleMap;
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (e.PropertyName.Equals("VisibleRegion") && !isDrawn)
{
map.Clear();
foreach (var pin in customPins)
{
var marker = new MarkerOptions();
marker.SetPosition(new LatLng(pin.Pin.Position.Latitude, pin.Pin.Position.Longitude));
marker.SetTitle(pin.Pin.Label);
marker.SetSnippet(pin.Pin.Address);
marker.SetIcon(BitmapDescriptorFactory.FromResource(Resource.Drawable.pin));
map.AddMarker(marker);
}
isDrawn = true;
}
}
protected override void OnLayout(bool changed, int l, int t, int r, int b)
{
base.OnLayout(changed, l, t, r, b);
if (changed)
{
isDrawn = false;
}
}
void OnInfoWindowClick(object sender, GoogleMap.InfoWindowClickEventArgs e)
{
var customPin = GetCustomPin(e.Marker);
if (customPin == null)
{
throw new Exception("Custom pin not found");
}
if (!string.IsNullOrWhiteSpace(customPin.Url))
{
var url = Android.Net.Uri.Parse(customPin.Url);
var intent = new Intent(Intent.ActionView, url);
intent.AddFlags(ActivityFlags.NewTask);
Android.App.Application.Context.StartActivity(intent);
}
}
public Android.Views.View GetInfoContents(Marker marker)
{
var inflater = Android.App.Application.Context.GetSystemService(Context.LayoutInflaterService) as Android.Views.LayoutInflater;
if (inflater != null)
{
Android.Views.View view;
var customPin = GetCustomPin(marker);
if (customPin == null)
{
throw new Exception("Custom pin not found");
}
if (customPin.Id == "Xamarin")
{
view = inflater.Inflate(Resource.Layout.XamarinMapInfoWindow, null);
}
else
{
view = inflater.Inflate(Resource.Layout.MapInfoWindow, null);
}
var infoTitle = view.FindViewById<TextView>(Resource.Id.InfoWindowTitle);
var infoSubtitle = view.FindViewById<TextView>(Resource.Id.InfoWindowSubtitle);
if (infoTitle != null)
{
infoTitle.Text = marker.Title;
}
if (infoSubtitle != null)
{
infoSubtitle.Text = marker.Snippet;
}
return view;
}
return null;
}
public Android.Views.View GetInfoWindow(Marker marker)
{
return null;
}
CustomPin GetCustomPin(Marker annotation)
{
var position = new Position(annotation.Position.Latitude, annotation.Position.Longitude);
foreach (var pin in customPins)
{
if (pin.Pin.Position == position)
{
return pin;
}
}
return null;
}
}
}
还有我的地图页面，也大量借用了 Xamarin 的地图使用指南
using Plugin.Geolocator;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using Xamarin.Forms;
using Xamarin.Forms.Maps;
using Xamarin.Forms.Xaml;
namespace WorkingWithMaps
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MainPage : ContentPage
{
CustomMap map;
Geocoder geoCoder;
String navAdd;
public MainPage()
{
InitializeComponent();
var maplocator = CrossGeolocator.Current;
maplocator.DesiredAccuracy = 1;
geoCoder = new Geocoder();
map = new CustomMap
{
HeightRequest = 100,
WidthRequest = 960,
VerticalOptions = LayoutOptions.FillAndExpand,
IsShowingUser = true
};
map.MapType = MapType.Street;
map.MoveToRegion(MapSpan.FromCenterAndRadius(new Position(55.237208, 10.479160), Distance.FromMeters(500)));
map.IsShowingUser = true;
var street = new Button { Text = "Street" };
var hybrid = new Button { Text = "Hybrid" };
var satellite = new Button { Text = "Satellite" };
street.Clicked += HandleClickedAsync;
hybrid.Clicked += HandleClickedAsync;
//satellite.Clicked += OnReverseGeocodeButtonClicked;
var segments = new StackLayout
{
Spacing = 30,
HorizontalOptions = LayoutOptions.CenterAndExpand,
Orientation = StackOrientation.Horizontal,
Children = { street, hybrid, satellite }
};
Content = new StackLayout
{
HorizontalOptions = LayoutOptions.Center,
Children = { map, segments }
};
Device.BeginInvokeOnMainThread(async () =>
{
try
{
//var currentpos = await maplocator.GetPositionAsync(1000);
//map.MoveToRegion(MapSpan.FromCenterAndRadius(new Position(currentpos.Latitude, currentpos.Longitude), Distance.FromMeters(500)));
if (!maplocator.IsListening)
{
await maplocator.StartListeningAsync(1000, 50, true);
}
}
catch (Exception ex)
{
Debug.WriteLine("Fail" + ex);
}
});
var pin = new CustomPin
{
Pin = new Pin
{
Type = PinType.Place,
Position = new Position(55.240121, 10.469895),
Label = "Testing Pins"
}
};
map.CustomPins = new List<CustomPin> { pin };
map.Pins.Add(pin.Pin);
map.PropertyChanged += (sender, e) =>
{
Debug.WriteLine(e.PropertyName + " just changed!");
if (e.PropertyName == "VisibleRegion" && map.VisibleRegion != null)
CalculateBoundingCoordinates(map.VisibleRegion);
};
maplocator.PositionChanged += (sender, e) =>
{
var position = e.Position;
map.MoveToRegion(MapSpan.FromCenterAndRadius(new Position(position.Latitude, position.Longitude), Distance.FromKilometers(2)));
};
}
/// <summary>
///
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
//async void OnReverseGeocodeButtonClicked(object sender, EventArgs e)
//{
// var possibleAddresses = await geoCoder.GetAddressesForPositionAsync(pin.Position);
// navAdd += possibleAddresses.ElementAt(0) + "\n";
// switch (Device.OS)
// {
// case TargetPlatform.iOS:
// Device.OpenUri(new Uri(string.Format("http://maps.apple.com/?q={0}", WebUtility.UrlEncode(navAdd))));
// break;
// case TargetPlatform.Android:
// Device.OpenUri(new Uri(string.Format("geo:0,0?q={0}", WebUtility.UrlEncode(navAdd))));
// break;
// case TargetPlatform.Windows:
// case TargetPlatform.WinPhone:
// Device.OpenUri(new Uri(string.Format("bingmaps:?where={0}", Uri.EscapeDataString(navAdd))));
// break;
// }
//}
void HandleClickedAsync(object sender, EventArgs e)
{
var b = sender as Button;
switch (b.Text)
{
case "Street":
map.MapType = MapType.Street;
break;
case "Hybrid":
map.MapType = MapType.Hybrid;
break;
case "Satellite":
map.MapType = MapType.Satellite;
break;
}
}
static void CalculateBoundingCoordinates(MapSpan region)
{
var center = region.Center;
var halfheightDegrees = region.LatitudeDegrees / 2;
var halfwidthDegrees = region.LongitudeDegrees / 2;
var left = center.Longitude - halfwidthDegrees;
var right = center.Longitude + halfwidthDegrees;
var top = center.Latitude + halfheightDegrees;
var bottom = center.Latitude - halfheightDegrees;
if (left < -180) left = 180 + (180 + left);
if (right > 180) right = (right - 180) - 180;
Debug.WriteLine("Bounding box:");
Debug.WriteLine(" " + top);
Debug.WriteLine(" " + left + " " + right);
Debug.WriteLine(" " + bottom);
}
}
}
除了上述问题之外，实施还导致
IsShowingUser = Truevar currentpos = await maplocator.GetPositionAsync(1000);
抛出异常。
2个回答
3
投票
投票
首先我想提供两个帮助我理解问题的链接。感谢你们。 Xamarin.Forms.Maps 2.3.4 自定义 MapRenderer 禁用所有功能 和 https://forums.xamarin.com/discussion/92565/android-ionmapreadycallback-forms-2-3-4
最新的 Xamarin Maps 打破了 OnElementPropertyChanged 与 VisibleRegion 的关系。他们定义 MapRenderer 现在实现了 IOnMapReadyCallback 并且以某种方式破坏了 OnElementPropertyChanged （我没有调查如何以及为什么）。正如您在我提供的链接中看到的，您可以采用两种方法。保持渲染器实现 IOnMapReadyCallback 或不实现。当我保留 IOnMapReadyCallback 时，我开始获得 2 个引脚 - 一个位于顶部，另一个 - 我们的自定义引脚和常规引脚。我没有进一步挖掘这是如何发生的，并删除了 IOnMapReadyCallback。之后事情变得非常简单，因为如果您让 Xamarin 处理它并创建 NativeMap，您可以删除一些代码并使渲染器更简单。
在发布代码之前，我还想提一下，当我修复它时，应用程序开始因 OutOfMemory 异常而崩溃，并且我发现您的 pin 图像的宽度为 2000 像素。我把它改成了40。下面是代码：
public class CustomMapRenderer : MapRenderer, GoogleMap.IInfoWindowAdapter//, IOnMapReadyCallback
{
bool isDrawn;
protected override void OnElementChanged(Xamarin.Forms.Platform.Android.ElementChangedEventArgs<Map> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
NativeMap.InfoWindowClick -= OnInfoWindowClick;
}
}
bool isMapReady;
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (!isMapReady && (NativeMap != null))
{
NativeMap.SetInfoWindowAdapter(this);
NativeMap.InfoWindowClick += OnInfoWindowClick;
isMapReady = true;
}
if (e.PropertyName.Equals("VisibleRegion") && !isDrawn)
{
NativeMap.Clear();
foreach (var pin in ((CustomMap)Element).CustomPins)
{
var marker = new MarkerOptions();
marker.SetPosition(new LatLng(pin.Pin.Position.Latitude, pin.Pin.Position.Longitude));
marker.SetTitle(pin.Pin.Label);
marker.SetSnippet(pin.Pin.Address);
marker.SetIcon(BitmapDescriptorFactory.FromResource(Resource.Drawable.pin));
NativeMap.AddMarker(marker);
}
isDrawn = true;
}
}
protected override void OnLayout(bool changed, int l, int t, int r, int b)
{
base.OnLayout(changed, l, t, r, b);
if (changed)
{
isDrawn = false;
}
}
void OnInfoWindowClick(object sender, GoogleMap.InfoWindowClickEventArgs e)
{
var customPin = GetCustomPin(e.Marker);
if (customPin == null)
{
throw new Exception("Custom pin not found");
}
if (!string.IsNullOrWhiteSpace(customPin.Url))
{
var url = Android.Net.Uri.Parse(customPin.Url);
var intent = new Intent(Intent.ActionView, url);
intent.AddFlags(ActivityFlags.NewTask);
Android.App.Application.Context.StartActivity(intent);
}
}
public Android.Views.View GetInfoContents(Marker marker)
{
var inflater = Android.App.Application.Context.GetSystemService(Context.LayoutInflaterService) as Android.Views.LayoutInflater;
if (inflater != null)
{
Android.Views.View view;
var customPin = GetCustomPin(marker);
if (customPin == null)
{
throw new Exception("Custom pin not found");
}
if (customPin.Id == "Xamarin")
{
view = inflater.Inflate(Resource.Layout.XamarinMapInfoWindow, null);
}
else
{
view = inflater.Inflate(Resource.Layout.MapInfoWindow, null);
}
var infoTitle = view.FindViewById<TextView>(Resource.Id.InfoWindowTitle);
var infoSubtitle = view.FindViewById<TextView>(Resource.Id.InfoWindowSubtitle);
if (infoTitle != null)
{
infoTitle.Text = marker.Title;
}
if (infoSubtitle != null)
{
infoSubtitle.Text = marker.Snippet;
}
return view;
}
return null;
}
public Android.Views.View GetInfoWindow(Marker marker)
{
return null;
}
CustomPin GetCustomPin(Marker annotation)
{
var position = new Position(annotation.Position.Latitude, annotation.Position.Longitude);
foreach (var pin in ((CustomMap)Element).CustomPins)
{
if (pin.Pin.Position == position)
{
return pin;
}
}
return null;
}
}
0
投票
投票
使用该命令可以使用map.onCreate(mapViewBundle);这是一个消息：Google Map 不涉及 map.onCreate(mapViewBundle); 的定义。 Alguem consegue me ajudar？
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