Question

我有一张地图，我在上面画了一个多边形。绘制初始多边形后，我将地图旋转一圈，每次1度，在大约5秒钟内完成一个完整的圆圈。

问题是我希望多边形保持在屏幕上的相同位置，而不是在地图上。如果在旋转地图时我对多边形不执行任何操作，则多边形也会旋转。这不是理想的行为，我希望多边形在旋转地图时保持在屏幕上的相同位置。

我尝试使用以下方法来获取新的多点但是它没有正确出现。我一直使用0和135轴承作为我的测试，结果如下所示。

方法：

//degrees = counter-clockwise from north
private List<LatLng> getPolygonPoints(LatLng startPoint, int bearing) {
    LatLng firstPoint = getPolyPoint(startPoint, 100, getPolyPointDifference(90, bearing));
    LatLng fourthPoint = getPolyPoint(startPoint, 100, getPolyPointDifference(270, bearing));

    LatLng secondPoint = getPolyPoint(firstPoint, 300, getPolyPointDifference(10, bearing));
    LatLng thirdPoint = getPolyPoint(fourthPoint, 300, getPolyPointDifference(350, bearing));

    return Arrays.asList(
        startPoint,
        firstPoint,
        secondPoint,
        thirdPoint,
        fourthPoint,
        startPoint
    );
}

private int getPolyPointDifference(int fromNorth, int bearing) {
    int[] compass = new int[360];
    int currentBearing = 360 - bearing;

    if (currentBearing == 360) {
        currentBearing = 0;
    }

    for (int i = 0; i < 360; i++) {
        compass[i] = currentBearing;
        currentBearing++;

        if (currentBearing >= 360) {
            currentBearing = 0;
        }
    }

    Log.i(LOG_TAG, "fromNorth: "+fromNorth+" return: "+compass[fromNorth]);

    return compass[fromNorth];
}

//distance = meters
//degrees = counter-clockwise from north
private LatLng getPolyPoint(LatLng fromLocation, int distance, int degrees) {
    double radians = (degrees * Math.PI) / 180;

    double distanceX = distance * Math.sin(radians);
    double distanceY = distance * Math.cos(radians);

    double deltaLatitude = distanceY / 110540;
    double deltaLongitude = distanceX / (111320 * Math.cos(fromLocation.latitude));

    double pointLatitude = fromLocation.latitude + deltaLatitude;
    double pointLongitude = fromLocation.longitude + deltaLongitude;

    return new LatLng(pointLatitude, pointLongitude);
}

输出：

轴承= 0

fromNorth：90 return：90
fromNorth：270 return：270
fromNorth：10 return：10
fromNorth：350 return：350

方位= 135

fromNorth：90 return：315
fromNorth：270 return：135
fromNorth：10 return：235
fromNorth：350返回：215

结果：

Bearing 0

Bearing 135

Answer 1

问题是我希望多边形保持在屏幕上的相同位置，而不是地图上。

然后不要在地图上绘制它，而是在你创建的覆盖表面上绘制。

Android旋转地图但将多边形留在同一屏幕位置

1 个答案: