谷歌地图API V2调整大小的屏幕匹配画出的圆圈 [英] Google map api V2 resize screen to match a circle drawn

问题描述

我绘制在地图上的圆（在用户的当前位置），我想在屏幕放大到具有圆全屏一些余量。我在做什么现在：

I am drawing a circle in a map (on the current location of the user) and I want the screen to zoom to have the circle in full screen with some margin. What I'm doing for now:

drawCercleAroundPin(_googleMap, DataManager.RADIUS_SEARCH_CERCLE, _location);

moveCamera(_googleMap, (10 / ((DataManager.RADIUS_SEARCH_CERCLE / 900) + 1))+10, 2000, _location, null);

嗯，我尝试了一些愚蠢的演算，因为我没能找到一个妥善的解决办法...

Well I tried some idiotic calculus since i wasn't able to find a proper solution...

有没有人有一个想法？

推荐答案

如果我理解正确的话，你希望你的地图，以适应圈的边界？如果是这样

If I understand correctly,you want your map to fit circle bounds ? If so

补充就像一个圆<一个href="http://stackoverflow.com/questions/6224671/mkcoordinateregionmakewithdistance-equvivalent-in-android">this

mMap.addCircle(new CircleOptions()
        .center(new LatLng(location.getLatitude(), location.getLongitude()))
        .radius(100)
        .strokeColor(Color.RED)
        .fillColor(Color.BLUE));

*的然后你需要包围的圈子中，阅读<一个href="http://stackoverflow.com/questions/15319431/how-to-convert-a-latlng-and-a-radius-to-a-latlngbounds-in-android-google-maps-ap">this * 的

*then you need bounding box of your circle,read this *

LatLngBounds bounds = boundsWithCenterAndLatLngDistance(new LatLng(location.getLatitude(), location.getLongitude()),200,200);

*的，并尝试* 的

private static final double ASSUMED_INIT_LATLNG_DIFF = 1.0;
private static final float ACCURACY = 0.01f;

public static LatLngBounds boundsWithCenterAndLatLngDistance(LatLng center, float latDistanceInMeters, float lngDistanceInMeters) {
    latDistanceInMeters /= 2;
    lngDistanceInMeters /= 2;
    LatLngBounds.Builder builder = LatLngBounds.builder();
    float[] distance = new float[1];
    {
        boolean foundMax = false;
        double foundMinLngDiff = 0;
        double assumedLngDiff = ASSUMED_INIT_LATLNG_DIFF;
        do {
            Location.distanceBetween(center.latitude, center.longitude, center.latitude, center.longitude + assumedLngDiff, distance);
            float distanceDiff = distance[0] - lngDistanceInMeters;
            if (distanceDiff < 0) {
                if (!foundMax) {
                    foundMinLngDiff = assumedLngDiff;
                    assumedLngDiff *= 2;
                } else {
                    double tmp = assumedLngDiff;
                    assumedLngDiff += (assumedLngDiff - foundMinLngDiff) / 2;
                    foundMinLngDiff = tmp;
                }
            } else {
                assumedLngDiff -= (assumedLngDiff - foundMinLngDiff) / 2;
                foundMax = true;
            }
        } while (Math.abs(distance[0] - lngDistanceInMeters) > lngDistanceInMeters * ACCURACY);
        LatLng east = new LatLng(center.latitude, center.longitude + assumedLngDiff);
        builder.include(east);
        LatLng west = new LatLng(center.latitude, center.longitude - assumedLngDiff);
        builder.include(west);
    }
    {
        boolean foundMax = false;
        double foundMinLatDiff = 0;
        double assumedLatDiffNorth = ASSUMED_INIT_LATLNG_DIFF;
        do {
            Location.distanceBetween(center.latitude, center.longitude, center.latitude + assumedLatDiffNorth, center.longitude, distance);
            float distanceDiff = distance[0] - latDistanceInMeters;
            if (distanceDiff < 0) {
                if (!foundMax) {
                    foundMinLatDiff = assumedLatDiffNorth;
                    assumedLatDiffNorth *= 2;
                } else {
                    double tmp = assumedLatDiffNorth;
                    assumedLatDiffNorth += (assumedLatDiffNorth - foundMinLatDiff) / 2;
                    foundMinLatDiff = tmp;
                }
            } else {
                assumedLatDiffNorth -= (assumedLatDiffNorth - foundMinLatDiff) / 2;
                foundMax = true;
            }
        } while (Math.abs(distance[0] - latDistanceInMeters) > latDistanceInMeters * ACCURACY);
        LatLng north = new LatLng(center.latitude + assumedLatDiffNorth, center.longitude);
        builder.include(north);
    }
    {
        boolean foundMax = false;
        double foundMinLatDiff = 0;
        double assumedLatDiffSouth = ASSUMED_INIT_LATLNG_DIFF;
        do {
            Location.distanceBetween(center.latitude, center.longitude, center.latitude - assumedLatDiffSouth, center.longitude, distance);
            float distanceDiff = distance[0] - latDistanceInMeters;
            if (distanceDiff < 0) {
                if (!foundMax) {
                    foundMinLatDiff = assumedLatDiffSouth;
                    assumedLatDiffSouth *= 2;
                } else {
                    double tmp = assumedLatDiffSouth;
                    assumedLatDiffSouth += (assumedLatDiffSouth - foundMinLatDiff) / 2;
                    foundMinLatDiff = tmp;
                }
            } else {
                assumedLatDiffSouth -= (assumedLatDiffSouth - foundMinLatDiff) / 2;
                foundMax = true;
            }
        } while (Math.abs(distance[0] - latDistanceInMeters) > latDistanceInMeters * ACCURACY);
        LatLng south = new LatLng(center.latitude - assumedLatDiffSouth, center.longitude);
        builder.include(south);
    }
    return builder.build();
}

最后调用

CameraUpdateFactory#newLatLngBounds(bounds, padding);

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