Question

我查看了documentation of polyline，没有选项让它破灭。

有人知道如何用android google map sdk v2绘制虚线折线吗？

Answer 1

现在在Polyline中，您可以将模式设置为Dash，Dot或Gap 只需应用以下

public static final int PATTERN_DASH_LENGTH_PX = 20;
public static final int PATTERN_GAP_LENGTH_PX = 20;
public static final PatternItem DOT = new Dot();
public static final PatternItem DASH = new Dash(PATTERN_DASH_LENGTH_PX);
public static final PatternItem GAP = new Gap(PATTERN_GAP_LENGTH_PX);
public static final List<PatternItem> PATTERN_POLYGON_ALPHA = Arrays.asList(GAP, DASH);

 private void drawDashedLeg(GoogleMap googleMap, Route route) {
    PolylineOptions polyOptions = new PolylineOptions();
    polyOptions.color(ContextCompat.getColor(getContext(), R.color.coolgrey));
    polyOptions.addAll(route.getPoints());
    polyOptions.pattern(PATTERN_POLYGON_ALPHA);
    Polyline polyline = googleMap.addPolyline(polyOptions);
    polylines.add(polyline);
}

Answer 2

Alexey，我刚刚创建了一个对我有用的功能，我认为这对你有用：

public static void createDashedLine(GoogleMap map, LatLng latLngOrig, LatLng latLngDest, int color){
    double difLat = latLngDest.latitude - latLngOrig.latitude;
    double difLng = latLngDest.longitude - latLngOrig.longitude;

    double zoom = map.getCameraPosition().zoom;

    double divLat = difLat / (zoom * 2);
    double divLng = difLng / (zoom * 2);

    LatLng tmpLatOri = latLngOrig;

    for(int i = 0; i < (zoom * 2); i++){
        LatLng loopLatLng = tmpLatOri;

        if(i > 0){
            loopLatLng = new LatLng(tmpLatOri.latitude + (divLat * 0.25f), tmpLatOri.longitude + (divLng * 0.25f));
        }

        Polyline polyline = map.addPolyline(new PolylineOptions()
            .add(loopLatLng)
            .add(new LatLng(tmpLatOri.latitude + divLat, tmpLatOri.longitude + divLng))
            .color(color)
            .width(5f));

        tmpLatOri = new LatLng(tmpLatOri.latitude + divLat, tmpLatOri.longitude + divLng);
    }
}

Answer 3

目前的版本无法实现。请按照此问题进行更新：https://code.google.com/p/gmaps-api-issues/issues/detail?id=4633

<强>更新

最近，Google在Google Maps Android API v2中为折线实现了此功能，并将问题4633标记为已修复。

请参阅Shapes Guide中有关笔画模式的信息。请参阅“折线和多边形”教程中的example。

您还可以在此处阅读相应的博文：

https://maps-apis.googleblog.com/2017/02/styling-and-custom-data-for-polylines.html

Answer 4

我创建了以下函数来绘制带有LatLng点列表的虚线折线。无论缩放如何，该算法都会创建0.002 kms（后跟0.002 kms米间隙）的线条。当您不想在缩放更改时重新绘制折线时，这非常有用。

private void drawDashedPolyLine(GoogleMap mMap, ArrayList<LatLng> listOfPoints, int color) {
    /* Boolean to control drawing alternate lines */
    boolean added = false;
    for (int i = 0; i < listOfPoints.size() - 1 ; i++) {
        /* Get distance between current and next point */
        double distance = getConvertedDistance(listOfPoints.get(i),listOfPoints.get(i + 1));

        /* If distance is less than 0.002 kms */
        if (distance < 0.002) {
            if (!added) {
                mMap.addPolyline(new PolylineOptions()
                        .add(listOfPoints.get(i))
                        .add(listOfPoints.get(i + 1))
                        .color(color));
                added = true;
            } else {/* Skip this piece */
                added = false;
            }
        } else {
            /* Get how many divisions to make of this line */
            int countOfDivisions = (int) ((distance/0.002));

            /* Get difference to add per lat/lng */
            double latdiff = (listOfPoints.get(i+1).latitude - listOfPoints
                    .get(i).latitude) / countOfDivisions;
            double lngdiff = (listOfPoints.get(i + 1).longitude - listOfPoints
                    .get(i).longitude) / countOfDivisions;

            /* Last known indicates start point of polyline. Initialized to ith point */
            LatLng lastKnowLatLng = new LatLng(listOfPoints.get(i).latitude, listOfPoints.get(i).longitude);
            for (int j = 0; j < countOfDivisions; j++) {

                /* Next point is point + diff */
                LatLng nextLatLng = new LatLng(lastKnowLatLng.latitude + latdiff, lastKnowLatLng.longitude + lngdiff);
                if (!added) {
                    mMap.addPolyline(new PolylineOptions()
                    .add(lastKnowLatLng)
                    .add(nextLatLng)
                    .color(color));
                    added = true;
                } else {
                    added = false;
                }
                lastKnowLatLng = nextLatLng;
            }
        }
    }
}

private double getConvertedDistance(LatLng latlng1, LatLng latlng2) {
    double distance = DistanceUtil.distance(latlng1.latitude,
            latlng1.longitude,
            latlng2.latitude,
            latlng2.longitude);
    BigDecimal bd = new BigDecimal(distance);
    BigDecimal res = bd.setScale(3, RoundingMode.DOWN);
    return res.doubleValue();
}

Util类计算两个LatLng之间的距离：

public class DistanceUtil {

    public static double distance(double lat1, double lon1, double lat2,
        double lon2) {

    if ((lat1 == lat2) && (lon1 == lon2)) {
        return 0;
    } else
        return distance(lat1, lon1, lat2, lon2, 'K');
    }

    public static double distance(double lat1, double lon1, double lat2,
        double lon2, char unit) {
        double theta = lon1 - lon2;
        double dist = Math.sin(deg2rad(lat1)) * Math.sin(deg2rad(lat2))
            + Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2))
            * Math.cos(deg2rad(theta));
        dist = Math.acos(dist);
        dist = rad2deg(dist);
        dist = dist * 60 * 1.1515;
        if (unit == 'K') {
            dist = dist * 1.609344;
        } else if (unit == 'N') {
            dist = dist * 0.8684;
        }
        return (dist);
    }

    private static double deg2rad(double deg) {
        return (deg * Math.PI / 180.0);
    }

    private static double rad2deg(double rad) {
        return (rad * 180.0 / Math.PI);
    }
}

注意：上述算法会生成大量折线，这些折线可能需要一段时间才能渲染。仅当点列表很小时才有用。

如何用android google map sdk v2绘制虚线折线？

4 个答案: