Android地图V2 - 动画的相机，包括最标志 [英] Android Maps v2 - animate camera to include most markers

问题描述

我有一组点从需要被显示在地图上一个Web服务来了。

I have a set of points coming from a webservice that need to be displayed on a map.

我有一个目前的解决方案很好地工作在大多数情况下，使用了著名的 LatLngBounds.Builder ， CameraUpdateFactory.newLatLngBounds 和 map.animateCamera 。

I have a current solution working nicely for most cases, using the well-known LatLngBounds.Builder, CameraUpdateFactory.newLatLngBounds and map.animateCamera.

我有一些情况下，这给问题，但：当点太远，对这些点的重心最大缩放级别的地图中心。例如：我有10个在法国和2个夏威夷。地图中心或多或少的caribeans在最小缩放级别。因此，在我得到了什么都不显示屏幕，用户滚动到实际看到的东西是存在的。

I have some cases which give problems though: when the points are too far away, the map centers on max zoom level on the barycenter of those points. For example: I have 10 points in France and 2 points in Hawai. Maps centers more or less on the caribeans at min zoom level. Hence on screen I got nothing shown, the user has to scroll to actually see something is there.

所以我的问题是：

有没有办法让地图缩小远远不够，这样我可以看到所有的点（这将是prefered）

is there a way to get the map to zoom out far enough so that I can see all points (that would be prefered)

或者：这将是过滤掉这些情况下，只有几个点很远的多数，并选择一个设定点的放大的（在我的例子中，最好的方法，我会选择缩小在10在法国分，忘记在夏威夷的那些）。

Or: which would be the best way to filter out those cases where just a few points are very far away from the majority and pick a set of point to zoom on (in my example, I would choose to zoom on the 10 points in France and forget about the ones in Hawai).

推荐答案

根据一些想法来自cYrixmorten，我简单的问题，因为我知道地图可以容纳至少4000公里的表面。因此，这里是建忽略摄像头（当时我根本不理会这摄像头的摄像头范围计算，但仍增加了标记，以便它是地图，如果用户对移动）。

Based on some ideas from cYrixmorten, I have simplified the problem because I know the map can accomodate at least 4000km of surface. So here is the function to build the list of ignored webcams (then I simply ignore that webcam for the camera bounds computation but still add the marker so that it is on the map if the user moves).

private List<Webcam> buildIgnoredWebcamsList(List<Webcam> webcams) {
    if (webcams == null || webcams.size() < 2) return Lists.newArrayList();

    int webcamCount = webcams.size();

    // Number of conflicts (distance > 4000 km) for the camera at index #
    float averageConflictCount = 0;
    int[] conflictCount = new int[webcamCount];
    Arrays.fill(conflictCount, 0);

    // Find number of conflicts between camera pairs
    float[] distance = new float[1];

    for (int i = 0; i < webcamCount - 1; ++i) {
        Webcam a = webcams.get(i);

                    // We don't have to start from 0, compare a and b only once
        for (int j = i + 1; j < webcamCount; ++j) {
            Webcam b = webcams.get(j);
            Location.distanceBetween(a.getLatitude(), a.getLongitude(), b.getLatitude(), b.getLongitude(), distance);

            // We have a conflict between a and b if they are more than 4000km away
            if (distance[0] > 4000 * 1000) {
                conflictCount[i] += 1;
                conflictCount[j] += 1;
                averageConflictCount += 2;
            }
        }
    }
    averageConflictCount /= webcamCount;

    // Exclude all webcams with a number of conflicts greater than the average
    List<Webcam> ignoredCamerasForBounds = Lists.newArrayList();

    for (int i = 0; i < webcamCount; ++i) {
        if (conflictCount[i] > averageConflictCount) {
            ignoredCamerasForBounds.add(webcams.get(i));
        }
    }

    return ignoredCamerasForBounds;
}

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