Java从for循环中寻找最小值

Question

我在尝试找到最小距离时遇到了一些问题，然后从最小距离开始，我在 map 上绘制了两个圆圈。

                    double distance = 0;
                    double minDistance;
                    convertedHotSpotGeomList = RetrieveHotSpotAsyncTask.convertedHotSpotGeom;
                    for(int i = 0; i < convertedHotSpotGeomList.size(); i++){
                        LatLng point1 = new LatLng(convertedHotSpotGeomList.get(i).getY(), convertedHotSpotGeomList.get(i).getX());                                 
                        LatLng point2 = new LatLng(convertedHotSpotGeomList.get(++i).getY(), convertedHotSpotGeomList.get(++i).getX());
                        distance = calculateHotSpot(point1, point2);
                        Log.i("DIST", String.valueOf(distance));
                        minDistance = distance;
                        if(minDistance < distance){
                            minDistance = distance;
                            Log.i("MIN", String.valueOf(minDistance));
                             CircleOptions circleOptions = new CircleOptions()
                                .center(point1)
                                .radius(1000)
                                .fillColor(Color.argb(95, 178, 30, 37))
                                .strokeColor(Color.TRANSPARENT);

                                googleBasemap.addCircle(circleOptions);

                                CircleOptions circleOptions1= new CircleOptions()
                                .center(point2)
                                .radius(1000)
                                .fillColor(Color.argb(95, 88, 130, 37))
                                .strokeColor(Color.TRANSPARENT);

                                googleBasemap.addCircle(circleOptions1);

                        }
                    }

目前我得到的 DIST 为 15, 3, 15, 14，但我无法获取 minDist，因为它没有打印出来。有什么想法吗？

提前致谢。

Answer 1

您可能想要:

    distance = calculateHotSpot(point1, point2);
    ....
    if(distance < minDistance){  
        minDistance = distance;

并初始化minDistance至Double.MAX_VALUE :double minDistance = Double.MAX_VALUE

原来的几行没有多大意义，因为minDistance < distance因为您刚刚设置 minDistance = distance; ，所以永远不会评估为 true

    distance = calculateHotSpot(point1, point2);
    ....
    minDistance = distance;
    if(minDistance < distance){ // will never happen
        minDistance = distance;

更新:

更完整的解决方案，因为上述问题并不是唯一的问题:

double minDistance = Double.MAX_VALUE;
convertedHotSpotGeomList = RetrieveHotSpotAsyncTask.convertedHotSpotGeom;
LatLng[] minPoints = new LatLng[2]; // save the minimum points
for(int i = 0; i < convertedHotSpotGeomList.size(); i++){
    LatLng point1 = new LatLng(convertedHotSpotGeomList.get(i).getY(),   convertedHotSpotGeomList.get(i).getX());                                 
    LatLng point2 = new LatLng(convertedHotSpotGeomList.get(++i).getY(), convertedHotSpotGeomList.get(++i).getX());
    distance = calculateHotSpot(point1, point2);
    Log.i("DIST", String.valueOf(distance));
    if(distance < minDistance){
        minDistance = distance;
        Log.i("MIN", String.valueOf(minDistance));
        minPoints[0] = point1;
        minPoints[1] = point2;
    }
}
// we finish all the comparison, so we draw the circles now 
if(minPoints[0]!=null && minPoints[1] !=null){
    CircleOptions circleOptions = new CircleOptions()
        .center(minPoints[0])
        .radius(1000)
        .fillColor(Color.argb(95, 178, 30, 37))
        .strokeColor(Color.TRANSPARENT);
    CircleOptions circleOptions1= new CircleOptions()
        .center(minPoints[1])
        .radius(1000)
        .fillColor(Color.argb(95, 88, 130, 37))
        .strokeColor(Color.TRANSPARENT);

    googleBasemap.addCircle(circleOptions);
    googleBasemap.addCircle(circleOptions1);
}