Question

我想在运行时向MapsForge添加一些Overlay项;我可以成功添加它们，但只有在我移动或缩放地图后它们才会出现。实际应该如此，因为每次移动或缩放时，MapsForge都会设法通过invalidate()函数重绘图块和重叠项目。无论如何，as it is stated here，这是一个已经修复的问题，因为MapsForge版本为0.2.0：MapView类应该能够在添加新项目时自动重绘。

我正在使用MapsForge 0.3.1。要么我做错了，要么这个问题在当前版本中重新出现。这是我的代码;我重用了the official MapsForge Sample activities中的一些代码：

public class MyMapView extends MapView{

    //I brought some variables outside the Sample's function in order to add new items dynamically to the lists
    ListOverlay mListOverlay;
    List<OverlayItem> mOverlayItems;
    Polyline mPolyline;
    Circle mLastPosition;

    //Basically here I do the same actions shown in the MapsForge samples. These items appear at once, with the onCreate() functions of the Activity
    public void addInitialOverlays(){
        Circle circle = createCircle(CENTRAL_STATION);
        Polygon polygon = createPolygon(Arrays.asList(VICTORY_COLUMN, CENTRAL_STATION, BRANDENBURG_GATE));
        mPolyline = createPolyline(Arrays.asList(BRANDENBURG_GATE, VICTORY_COLUMN));
        Marker marker1 = createMarker(R.drawable.marker_red, VICTORY_COLUMN);
        Marker marker2 = createMarker(R.drawable.marker_green, BRANDENBURG_GATE);

        mLastPosition = createCircle(VICTORY_COLUMN);

        mOverlayItems.add(circle);
        mOverlayItems.add(polygon);
        mOverlayItems.add(mPolyline);
        mOverlayItems.add(marker1);
        mOverlayItems.add(marker2);
        mOverlayItems.add(mLastPosition);
        getOverlays().add(mListOverlay);
    }

    //Here is the relevant part. This is called periodically from the main Activity
    public void addPointToRoute(double latitude, double longitude) {

        GeoPoint newPoint = new GeoPoint(latitude, longitude);
        //Tried both removing the list from the overlays and re-adding it, and leaving it where it is; same result
        //getOverlays().remove(mListOverlay);
        mOverlayItems.remove(mPolyline);
        List<GeoPoint> oldPolyline = mPolyline.getPolygonalChain().getGeoPoints();
        oldPolyline.add(newPoint);
        mPolyline = createPolyline(oldPolyline);
        mOverlayItems.add(mPolyline);
        mLastPosition.setGeoPoint(newPoint);
        //getOverlays().add(mListOverlay);

        invalidateOnUiThread();//This MapView function calls either invalidate() or postInvalidate(), depending on the situation
    }
}

Answer 1

尝试在添加叠加项后添加overlaycontroller

事实上，我发现你可以改用其他功能。

示例：

mapView.getOverlays().add(listOverlay);
//redraw once overlay items have been added/removed
mapView.getOverlayController().redrawOverlays(); //method 1
/**OR**/
mapView.redraw(); //method 2

希望这有帮助！

MapsForge动态添加的叠加项不会重绘

1 个答案: