android - Google Maps API 版本差异

Question

我正在尝试显示两地之间的路线，我想使用 Google Places API V3用于两点之间的路线步骤。

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在我使用 Old Google Maps API 之前，并且以下请求给出了完美的结果:

http://maps.google.com/maps?f=d&hl=en&saddr=19.5217608,-99.2615823&daddr=19.531224,-99.248262&ie=UTF8&0&om=0&output=kml

输出:

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现在我尝试用新的 Google Maps API 替换它，并且以下请求给出了错误的结果，在这两种情况下我都使用相同的源和目标，但结果在 Google Map 上给出了不同的行为:

http://maps.googleapis.com/maps/api/directions/json?origin=19.5217608,-99.2615823&destination=19.531224,-99.248262&sensor=false

我的问题是，新的 Google Maps API 在源和目的地之间返回的步数较少，因此该路线在 Google Map 上显示不完美。

请帮助解决新的 Google Maps API v3 的这个问题。

提前致谢。

Answer 1

我已获取您的请求 URL 并将其粘贴到我的应用程序中，该应用程序使用的是较新版本，并且效果很好。问题可能在于您如何解析数据或解码接收到的 JSON 字符串。

String url = "http://maps.googleapis.com/maps/api/directions/json?origin=19.5217608,-99.2615823&destination=19.531224,-99.248262&sensor=false";

HttpPost httppost = new HttpPost(url);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
InputStream is = null;
is = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
sb.append(reader.readLine() + "\n");
String line = "0";
while ((line = reader.readLine()) != null) {
    sb.append(line + "\n");
}
is.close();
reader.close();
String result = sb.toString();
JSONObject jsonObject = new JSONObject(result);
JSONArray routeArray = jsonObject.getJSONArray("routes");
JSONObject routes = routeArray.getJSONObject(0);
JSONObject overviewPolylines = routes.getJSONObject("overview_polyline");
String encodedString = overviewPolylines.getString("points");
List<GeoPoint> pointToDraw = decodePoly(encodedString);

//Added line:
mapView.getOverlays().add(new RoutePathOverlay(pointToDraw));

和 decodePoly() 方法取自 SO 中的另一个问题，我不记得作者了:

private List<GeoPoint> decodePoly(String encoded) {

    List<GeoPoint> poly = new ArrayList<GeoPoint>();
    int index = 0, len = encoded.length();
    int lat = 0, lng = 0;

    while (index < len) {
        int b, shift = 0, result = 0;
        do {
            b = encoded.charAt(index++) - 63;
            result |= (b & 0x1f) << shift;
            shift += 5;
        } while (b >= 0x20);
        int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
        lat += dlat;

        shift = 0;
        result = 0;
        do {
            b = encoded.charAt(index++) - 63;
            result |= (b & 0x1f) << shift;
            shift += 5;
        } while (b >= 0x20);
        int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
        lng += dlng;

        GeoPoint p = new GeoPoint((int) (((double) lat / 1E5) * 1E6), (int) (((double) lng / 1E5) * 1E6));
        poly.add(p);
    }

    return poly;
}

我还包括了我用来将叠加层添加到 map 本身的内容，我找不到它的教程。抱歉没有给予信任。 (在我发布的第一个方法中添加了对此的调用)

public class RoutePathOverlay extends Overlay {

    private int _pathColor;
    private final List<GeoPoint> _points;
    private boolean _drawStartEnd;

    public RoutePathOverlay(List<GeoPoint> points) {
            this(points, Color.RED, true);
    }

    public RoutePathOverlay(List<GeoPoint> points, int pathColor, boolean drawStartEnd) {
            _points = points;
            _pathColor = pathColor;
            _drawStartEnd = drawStartEnd;
    }


    private void drawOval(Canvas canvas, Paint paint, Point point) {
            Paint ovalPaint = new Paint(paint);
            ovalPaint.setStyle(Paint.Style.FILL_AND_STROKE);
            ovalPaint.setStrokeWidth(2);
            int _radius = 6;
            RectF oval = new RectF(point.x - _radius, point.y - _radius, point.x + _radius, point.y + _radius);
            canvas.drawOval(oval, ovalPaint);               
    }

    public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) {
            Projection projection = mapView.getProjection();
            if (shadow == false && _points != null) {
                    Point startPoint = null, endPoint = null;
                    Path path = new Path();
                    //We are creating the path
                    for (int i = 0; i < _points.size(); i++) {
                            GeoPoint gPointA = _points.get(i);
                            Point pointA = new Point();
                            projection.toPixels(gPointA, pointA);
                            if (i == 0) { //This is the start point
                                    startPoint = pointA;
                                    path.moveTo(pointA.x, pointA.y);
                            } else {
                                    if (i == _points.size() - 1)//This is the end point
                                            endPoint = pointA;
                                    path.lineTo(pointA.x, pointA.y);
                            }
                    }

                    Paint paint = new Paint();
                    paint.setAntiAlias(true);
                    paint.setColor(_pathColor);
                    paint.setStyle(Paint.Style.STROKE);
                    paint.setStrokeWidth(5);
                    paint.setAlpha(90);
                    if (getDrawStartEnd()) {
                            if (startPoint != null) {
                                    drawOval(canvas, paint, startPoint);
                            }
                            if (endPoint != null) {
                                    drawOval(canvas, paint, endPoint);
                            }
                    }
                    if (!path.isEmpty())
                            canvas.drawPath(path, paint);
            }
            return super.draw(canvas, mapView, shadow, when);
    }

    public boolean getDrawStartEnd() {
            return _drawStartEnd;
    }

    public void setDrawStartEnd(boolean markStartEnd) {
            _drawStartEnd = markStartEnd;
    }
}

希望这对你有用。