java - Android计算Android Google map 中的网格角位置

我想在Googmap上围4行3列。我想在网格所组成的每个矩形的topLeft和右下角显示标记。

这是我正在使用的代码

public void getVisibleRegionGrids(final VisibleRegion region)
{
    int columns = 3;
    int rows    = 4;

    double mainTopLat  = region.latLngBounds.southwest.latitude;  // (c, d)
    double mainTopLng  = region.latLngBounds.northeast.longitude;

    double mainBottomLat = region.latLngBounds.northeast.latitude;
    double mainBottomLng = region.latLngBounds.southwest.longitude;

    double horizontalDiff = Math.abs (( mainBottomLat - mainTopLat ) / columns);  // 1
    double verticalDiff   = Math.abs (( mainBottomLng - mainTopLng ) / rows);  // 1

    double topLat  = mainTopLat;  // (c, d)
    double topLng  = mainTopLng;

    //double bottomLat = mainTopLat + horizontalDiff;
    //double bottomLng = mainTopLng + verticalDiff;

    for (int i = 0; i < rows; i++)
    {
        for (int x = 0; x < columns ; x++)
        {
            double currentTopLat = (topLat + (i * verticalDiff)) + (x * horizontalDiff);
            double currentTopLng = (topLng + (i * verticalDiff)) + (x * horizontalDiff);

            double currentBottomLat = currentTopLat + horizontalDiff;
            double currentBottomLng = currentTopLng + verticalDiff;
            try
            {
                MarkerOptions markerOptions = new MarkerOptions()
                        .draggable(false)
                        .position(new LatLng(Double.valueOf(currentTopLat), Double.valueOf(currentTopLng))
                        );
                mMap.addMarker(markerOptions);

                markerOptions = new MarkerOptions()
                        .draggable(false)
                        .position(new LatLng(Double.valueOf(currentBottomLat), Double.valueOf(currentBottomLng))
                );
                mMap.addMarker(markerOptions);

            }catch (Exception e)
            {}
        }
    }
}

我无法使其逻辑正常工作。我已经计算了topLeft和右下角的点。从topLeft开始，我要继续。我能做什么

更新资料

有了帮助，我设法使它起作用

public void getVisibleRegionGrids(final VisibleRegion region)
{
    int columns = 3;
    int rows    = 4;

    double mainTopLat  = region.latLngBounds.northeast.latitude;  // (c, d)
    double mainMaxLng  = region.latLngBounds.northeast.longitude;

    double mainBottomLat = region.latLngBounds.southwest.latitude;
    double mainMinLng = region.latLngBounds.southwest.longitude;

    double horizontalDiff = Math.abs ((mainMaxLng - mainMinLng ) / columns);  // 1
    double verticalDiff   = Math.abs ((mainTopLat - mainBottomLat) / rows);  // 1

    double topLat = mainTopLat;  // (c, d)
    double topLng = mainMinLng;
    int position = 0;

    for (int i = 0; i < rows; i++)
    {
        for (int x = 0; x < columns ; x++)
        {
            double currentTopLat  = (topLat - (i * verticalDiff));
            double currentLeftLng = (topLng + (x * horizontalDiff));

            if(position == i)
            {
                currentTopLat  = (topLat - (i * verticalDiff));
                currentLeftLng = (topLng + (x * horizontalDiff));
            }

            position = -1;

            if(x == columns)
                position = i + 1;

            try
            {
                MarkerOptions markerOptions = new MarkerOptions()
                        .draggable(false)
                        .position(new LatLng(Double.valueOf(currentTopLat), Double.valueOf(currentLeftLng)));
                mMap.addMarker(markerOptions);

                double currentBottomLat = currentTopLat - verticalDiff;
                double currentRightLng = currentLeftLng + horizontalDiff;
                markerOptions = new MarkerOptions()
                        .draggable(false)
                        .position(new LatLng(Double.valueOf(currentBottomLat), Double.valueOf(currentRightLng)));
                mMap.addMarker(markerOptions);

            }catch (Exception e)
            {}
        }
    }
}

最佳答案

您的代码似乎有一些关于坐标的错误。
西南是左下角，东北是右上角。
所以


mainTopLat是northeast.latitude
mainTopLng是northeast.longitude->应称为mainMaxLng
mainBottomLat位于西南。
mainBottomLng是southwest.longitude->应称为mainMinLng


我正在内联修改代码，因此可能包含错误，但它应适合您的情况。除最后一行和最后一列外，请勿绘制右下标记，因为它会绘制重复的标记！

public void getVisibleRegionGrids(final VisibleRegion region)
{
    int columns = 3;
    int rows    = 4;

    double mainTopLat  = region.latLngBounds.northeast.latitude;  // (c, d)
    double mainMaxLng  = region.latLngBounds.northeast.longitude;

    double mainBottomLat = region.latLngBounds.southwest.latitude;
    double mainMinLng = region.latLngBounds.southwest.longitude;

    double horizontalDiff = Math.abs ((mainMaxLng - mainMinLng ) / columns);  // 1
    double verticalDiff   = Math.abs (( mainTopLat - mainBottomLat) / rows);  // 1

    double topLat  = mainTopLat;  // (c, d)
    double rightLng  = mainMaxLng;

    for (int i = 0; i < rows; i++)
    {
        for (int x = 0; x < columns ; x++)
        {
            double currentTopLat = (topLat - (i * verticalDiff));
            double currentLeftLng = (topLng + (x * horizontalDiff));

            try
            {
                MarkerOptions markerOptions = new MarkerOptions()
                        .draggable(false)
                        .position(new LatLng(Double.valueOf(currentTopLat), Double.valueOf(currentLeftLng)));
                mMap.addMarker(markerOptions);

                if ((i==(rows-1))|| (x==columns-1){//add the lowerright marker only on the last line or column, avoid duplicated markers
                double currentBottomLat = currentTopLat - verticalDiff;
                double currentRightLng = currentLeftLng + horizontalDiff;
                markerOptions = new MarkerOptions()
                                .draggable(false)
                                .position(new LatLng(Double.valueOf(currentBottomLat), Double.valueOf(currentBottomLng)));
                    mMap.addMarker(markerOptions);
    }
            }catch (Exception e)
            {}
        }
    }
}

关于java - Android计算Android Google map 中的网格角位置，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/31042396/