我正在尝试创建一个包含MapView和ListView的活动。我使用 C# 和 MonoDroid。
布局如下所示
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<app.MD.UI.PlacesMapView
android:id="@+id/mapView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:enabled="true"
android:clickable="true"
android:layout_weight="1"
android:apiKey="key" />
<ListView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:id="@+id/resultsTable" />
</LinearLayout>
我的自定义 MapView 类实现了长按处理程序
private void HandleLongPress(MotionEvent e)
{
if (e.Action == MotionEventActions.Down) {
// Finger has touched screen.
longpressTimer = new Timer(LONGPRESS_THRESHOLD);
longpressTimer.AutoReset = false;
longpressTimer.Elapsed += delegate(object sender, ElapsedEventArgs e_elapsed) {
GeoPoint longpressLocation = Projection.FromPixels((int)e.GetX(), (int)e.GetY());
if (OnLongPress != null) {
OnMapViewLongPressEventArgs args = new OnMapViewLongPressEventArgs();
args.location = longpressLocation;
OnLongPress(this, args);
}
};
longpressTimer.Start();
lastMapCenter = MapCenter;
}
if (e.Action == MotionEventActions.Move) {
if (!MapCenter.Equals(lastMapCenter)) {
longpressTimer.Stop();
}
lastMapCenter = MapCenter;
}
if (e.Action == MotionEventActions.Up) {
// User has removed finger from map.
longpressTimer.Stop();
}
if (e.PointerCount > 1) {
// This is a multitouch event, probably zooming.
longpressTimer.Stop();
}
}
活动方法,用于将标记添加到地图视图
protected void AddPinToMap(GeoPoint location, string title, bool scrollTo, int zoom)
{
var pin = Resources.GetDrawable(Resource.Drawable.maps_pin);
PinOverlay pinOverlay = new PinOverlay(pin, this);
OverlayItem item = new OverlayItem(location, title, "");
pinOverlay.AddOverlay(item);
mapView.Overlays.Clear();
mapView.Overlays.Add(pinOverlay);
if (scrollTo) {
mapView.Controller.AnimateTo(location);
}
mapView.Controller.SetZoom(zoom);
}
这是我的 PinOverlay 类
class PinOverlay : ItemizedOverlay
{
private List<OverlayItem> _items = new List<OverlayItem>();
private Context _context;
public PinOverlay(Drawable pin, Context context) : base(pin)
{
_context = context;
BoundCenterBottom(pin);
Populate();
}
protected override Java.Lang.Object CreateItem(int i)
{
return _items[i];
}
public override int Size()
{
return _items.Count();
}
public void AddOverlay(OverlayItem overlay) {
_items.Add(overlay);
Populate();
}
}
我的问题是,当我触摸MapView时,我的标记显示低于我触摸过的点。我认为这可能是由于我的MapView无法全屏显示的原因。当我删除ListView以便MapView可以占据整个屏幕时,我能够在屏幕上触摸的确切位置放置一个标记。
如果MapView只占用屏幕的一部分,如何处理触摸事件的任何建议或示例?
UPD找到了某种解决方法,仍然需要用不同的屏幕尺寸进行测试
转换触摸坐标
public static Point ConvertCoordinates(Context context, MapView mapView, double x, double y)
{
var wm = context.GetSystemService(Context.WindowService).JavaCast<IWindowManager>();
var display = wm.DefaultDisplay;
double diffY = (Convert.ToDouble(display.Height) / 2 - Convert.ToDouble(mapView.Height) / 2) / 2 - 20;
double diffX = Convert.ToDouble(display.Width) / 2 - Convert.ToDouble(mapView.Width) / 2;
Point size = new Point();
size.X = (int)(x - diffX);
size.Y = (int)(y - diffY);
return size;
}
像这样使用它
var point = MapHelper.ConvertCoordinates(this.Context, this, e.GetX(), e.GetY());
GeoPoint longpressLocation = Projection.FromPixels(point.X, point.Y);
你试过吗:
public PinOverlay(Drawable pin, Context context)
: base(BoundCenterBottom(pin))
这将使您放在地图上的Drawable
以点为中心,而不是在绘制地理坐标时将其作为 (x,y)(0,0) 坐标。
编辑:我似乎无法在这里重现您的问题,当在构造函数的:base()
中使用 BoundCenterBottom(pin) 时,它会很好地将我的Drawable
居中。
我还注意到在您的AddPinToMap
方法中,您每次都会创建一个新PinOverlay
。这应该是不必要的,您应该只向地图添加 1 次的PinOverlay
添加新OverlayItem
。如果您要向地图添加大量图钉,这将更高效且更少占用资源。
所以它应该看起来更像:
protected void AddPinToMap(GeoPoint location, string title, bool scrollTo, int zoom)
{
var pin = Resources.GetDrawable(Resource.Drawable.maps_pin);
OverlayItem item = new OverlayItem(location, title, "");
pinOverlay.AddOverlay(item); // this is instantiated in OnCreate
if (scrollTo) {
mapView.Controller.AnimateTo(location);
}
mapView.Controller.SetZoom(zoom);
}
并添加一个Remove
方法,如果您也希望能够删除OverlayItems
,PinOverlay
。
此外,MapView
已经有一个LongClick
事件,您可以挂钩而不是覆盖类:
var mapView = FindViewById<MapView>(Resource.Id.myMapView);
mapView.LongClick += (sender, args) => { //do whatever in here };
或
var mapView = FindViewById<MapView>(Resource.Id.myMapView);
mapView.LongClick += OnLongClick;
private void OnLongClick(object sender, LongClickEventArgs longClickEventArgs)
{
// do whatever in here
}
终于找到了问题的原因。
这部分是错误的,因为投影是在已用委托内部访问的。但到那时,投影已经改变了它的状态,这导致了错误的坐标。
if (e.Action == MotionEventActions.Down) {
// Finger has touched screen.
longpressTimer = new Timer(LONGPRESS_THRESHOLD);
longpressTimer.AutoReset = false;
longpressTimer.Elapsed += delegate(object sender, ElapsedEventArgs e_elapsed) {
GeoPoint longpressLocation = Projection.FromPixels((int)e.GetX(), (int)e.GetY());
if (OnLongPress != null) {
OnMapViewLongPressEventArgs args = new OnMapViewLongPressEventArgs();
args.location = longpressLocation;
OnLongPress(this, args);
}
};
longpressTimer.Start();
lastMapCenter = MapCenter;
}
因此,解决方案是在OnTouchEvent开始时获取GeoPoint。
if (e.Action == MotionEventActions.Down) {
capturedProjection = Projection.FromPixels((int)e.GetX(), (int)e.GetY());
// Finger has touched screen.
longpressTimer = new Timer(LONGPRESS_THRESHOLD);
longpressTimer.AutoReset = false;
longpressTimer.Elapsed += (object sender, ElapsedEventArgs e_timer) => {
if (OnLongPress != null) {
OnMapViewLongPressEventArgs args = new OnMapViewLongPressEventArgs();
args.location = capturedProjection;
OnLongPress(this, args);
}
};
longpressTimer.Start();
lastMapCenter = MapCenter;
}