将形状放入 Android 中的 MapView 中

Question

有没有办法在 MapView （纬度/经度区域）而不是像素区域中放置占据特定区域的形状（可绘制或任何类型的形状）。我需要它用于 GeoPoint 聚类目的，

如果不可能，任何使用投影坐标进行此操作的指导将不胜感激。但是使用 MapView 画布来执行此操作似乎并不明智，因为我一直在回收覆盖项目，并且我希望我也可以利用这一点。

Answer 1

查看ItemizedOverlay

我正在从我的代码中剔除，所以这可能不会'开箱即用地编译，但应该给你足够的东西从这里弄清楚......

扩展类：

    public class MyOverlay extends ItemizedOverlay<OverlayItem>
    {
    private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
    private Context mContext;
    private OverlayItem item;

    public MyOverlay(Drawable defaultMarker, Context context) 
    {
          super(boundCenterBottom(defaultMarker));
          mContext = context;
    }

    public void addOverlay(OverlayItem overlay) 
    {
        mOverlays.add(overlay);

    }

    public void doPopulate()
    {
         populate();
    }




    @Override
    protected OverlayItem createItem(int i) 
    { 
      return mOverlays.get(i);
    }

    @Override
    public int size() 
    {
      return mOverlays.size();
    }
}

然后在你的活动中......

public void addLocations(GeoPoint _center)
{  
    final GeoPoint center = _center;

    mapOverlays = mapView.getOverlays();

    Drawable drawable = MyActivity.this.getResources().getDrawable(R.drawable.map_annotation_pin);

    itemizedoverlay = new ScoopOverlay(drawable,mContext);

//add as many points as you wish...
itemizedoverlay.addOverlay(
                    new OverlayItem(new GeoPoint(/*lon lat data here*/));
                );



showResults.sendEmptyMessage(0);
}

private Handler showResults = new Handler() 
{ 
    @Override 
    public void handleMessage(Message msg) 
    { 
        itemizedoverlay.doPopulate();
        mapOverlays.add(itemizedoverlay);

        mapView.invalidate();
    }
}; 

Answer 2

因此，解决方案是绘制到保存项目的 ItemizedOverlay。

@Override
    public void draw(Canvas canvas, MapView mapView, boolean shadow) {
        super.draw(canvas, mapView, shadow);

        // cycle through all overlays
        for (int index = 0; index < mOverlays.size(); index++) {
            OverlayItemExtended item = mOverlays.get(index);

            // Converts lat/lng-Point to coordinates on the screen
            GeoPoint point = item.getPoint();
            Point ptScreenCoord = new Point();
            mapView.getProjection().toPixels(point, ptScreenCoord);



                Paint boxPaint = new Paint();
                boxPaint.setColor(android.graphics.Color.WHITE);
                boxPaint.setStyle(Paint.Style.FILL);
                boxPaint.setAlpha(140);
                canvas.drawCircle(ptScreenCoord.X, ptScreenCoord.y,
                        20, boxPaint);


        }

}