使用 Monodroid/Xamarin 在地图上绘制叠加层 [英] Draw Overlay on Map with Monodroid/Xamarin
问题描述
我正在尝试将图像叠加添加到自定义渲染器中的 Xamarin/Android 地图.
I am trying to add an image overlay to my Xamarin/Android map which is in a custom renderer.
我无法让它出现在地图上.这个食谱似乎过时了 http://developer.xamarin.com/recipes/android/control/mapview/add_an_overlay_to_a_map/ 或者我只是想念 Android.GoogleMaps.Overlay 类.
I cannot get it to appear on the map. This recipe seems outdated http://developer.xamarin.com/recipes/android/controls/mapview/add_an_overlay_to_a_map/ or I am just missing the Android.GoogleMaps.Overlay class somehow.
public class MapContentPageRenderer: PageRenderer
{
Android.Views.View _view;
private GoogleMap _map;
private MapFragment _mapFragment;
private LatLng _initLatLng;
protected override void OnElementChanged(ElementChangedEventArgs<Page> e)
{
base.OnElementChanged(e);
var page = e.NewElement as MapContentPage;
var activity = this.Context as Activity;
if (activity != null)
{
_view = activity.LayoutInflater.Inflate(Resource.Layout.MapLayout, this, false);
AddView(_view);
if (page != null) _initLatLng = new LatLng(page.InitLat, page.InitLng);
InitMapFragment(activity);
}
SetupMapIfNeeded();
}
protected override void OnLayout(bool changed, int l, int t, int r, int b)
{
base.OnLayout(changed, l, t, r, b);
var msw = MeasureSpec.MakeMeasureSpec(r - l, MeasureSpecMode.Exactly);
var msh = MeasureSpec.MakeMeasureSpec(b - t, MeasureSpecMode.Exactly);
if (_view == null) return;
_view.Measure(msw, msh);
_view.Layout(0, 0, r - l, b - t);
}
private void InitMapFragment(Activity activity)
{
var cameraPosition = new CameraPosition.Builder().Target(_initLatLng).Zoom(14.0f).Build();
_mapFragment = activity.FragmentManager.FindFragmentByTag("mapWithOverlay") as MapFragment;
if (_mapFragment != null) return;
var mapOptions = new GoogleMapOptions()
.InvokeMapType(GoogleMap.MapTypeNormal)
.InvokeRotateGesturesEnabled(false)
.InvokeZoomControlsEnabled(false)
.InvokeCamera(cameraPosition)
.InvokeCompassEnabled(true);
var fragTx = activity.FragmentManager.BeginTransaction();
_mapFragment = MapFragment.NewInstance(mapOptions);
fragTx.Add(Resource.Id.mapWithOverlay, _mapFragment, "mapWithOverlay");
fragTx.Commit();
}
private void SetupMapIfNeeded()
{
if (_map != null) return;
_map = _mapFragment.Map;
if (_map == null) return;
ZoomToPosition();
var mapOverlay = new GroundOverlayOptions()
.Position(_initLatLng, 150, 200)
.InvokeImage(BitmapDescriptorFactory.FromResource(Resource.Drawable.Icon));
_map.AddGroundOverlay(mapOverlay);
}
private void ZoomToPosition()
{
var cameraUpdate = CameraUpdateFactory.NewLatLngZoom(_initLatLng, 15);
_map.MoveCamera(cameraUpdate);
}
}
推荐答案
Android.GoogleMaps.Overlay 已弃用.
既然如此，您不应该尝试将其用作链接您发布的已过期.
Being so you should not attempt to use this as the example in the link you posted is out-of-date.
相反，您应该使用 GroundOverlay 或 TileOverlay for Android GoogleMaps，或其他<强>叠加适用于您要实现的目标.
Instead you should use a GroundOverlay or a TileOverlay for Android GoogleMaps, or one of the other overlays that are applicable depending on what you are trying to achieve.
更新 1:-
这是一个创建自定义GroundOverlay的示例:-
Here is an example that creates a custom GroundOverlay of:-
- 100 x 100 像素
- 绘制一个红色的半透明圆圈
- 然后是一些显示18"的黄色文本
cobjGoogleMap 将是 GoogleMap 类型的地图引用，之前已经定义和引用过.
cobjGoogleMap would be your map reference of type GoogleMap, already previously defined and referenced.
就像您拥有的参考 link 一样，它创建了画布，并展示如何在将画布添加到地图之前在画布上绘制一些东西.希望这能让您走上创建自定义绘制叠加层的正确道路?
Like in the reference link that you had, it creates a Canvas and shows how to draw a couple things on this canvas, prior to adding this to the map. Hopefully this should set you on the right path to creating your custom drawn overlays?
private GroundOverlay cobjGroundOverlay = null;
private void AddMyCustomDrawnOverlayToMap()
{
LatLng objMapPosition = new LatLng(51, -1.1);
int intWidth = 100;
int intHeight = 100;
//
using (Bitmap objBitmap = GenerateMyCustomDrawnOverlay(intWidth, intHeight))
{
using (Android.Gms.Maps.Model.BitmapDescriptor objBitmapDescriptor = Android.Gms.Maps.Model.BitmapDescriptorFactory.FromBitmap(objBitmap))
{
GroundOverlayOptions objGroundOverlayOptions = new GroundOverlayOptions()
.Position(objMapPosition, intWidth, intHeight)
.InvokeImage(objBitmapDescriptor);
//
cobjGroundOverlay = cobjGoogleMap.AddGroundOverlay(objGroundOverlayOptions);
}
}
//
// Move the camera to the position where we added the new ground overlay:-
CameraUpdate objCameraUpdate = CameraUpdateFactory.NewLatLngZoom(objMapPosition, 17);
cobjGoogleMap.MoveCamera(objCameraUpdate);
}
private Bitmap GenerateMyCustomDrawnOverlay(int pintWidth, int pintHeight)
{
// Create your custom overlay Bitmap using a Canvas object:-
//
var objPaint = new global::Android.Graphics.Paint();
objPaint.AntiAlias = true;
objPaint.Color = global::Android.Graphics.Color.Red;
objPaint.Alpha = 150;
//
var objPaint2 = new global::Android.Graphics.Paint();
objPaint2.AntiAlias = true;
objPaint2.Color = global::Android.Graphics.Color.Yellow;
objPaint2.TextSize = 90;
objPaint2.Alpha = 255;
//
Bitmap objBitmap = Bitmap.CreateBitmap(pintWidth, pintHeight, Bitmap.Config.Argb8888);
Canvas objCanvas = new Canvas(objBitmap);
//
int intHalfWidth = pintWidth / 2;
int intHalfHeight = pintHeight / 2;
//
// Draw a circle (red / semi-transparent):-
objCanvas.DrawRoundRect(new global::Android.Graphics.RectF(0, 0, (float)pintWidth, (float)pintHeight), intHalfWidth, intHalfHeight, objPaint);
//
// Draw some text, although your probably want to do MeasureText etc in order to center things properly:-
objCanvas.DrawText("18", 0, 80, objPaint2);
//
// Return the bitmap that will be used:-
return objBitmap;
}
这篇关于使用 Monodroid/Xamarin 在地图上绘制叠加层的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
