XML解析和排序

Question

我有下面的XML文件，其中包含需要查找到站点的最短距离的站点。

<station>
<station_id>TAPA</station_id>
<latitude>17.117</latitude>
<longitude>-61.783</longitude>
<xml_url>http://weather.gov/xml/current_obs/TAPA.xml</xml_url>
</station>

<station>
<station_id>TKPN</station_id>
<latitude>17.2</latitude>
<longitude>-62.583</longitude>
<xml_url>http://weather.gov/xml/current_obs/TKPN.xml</xml_url>
</station>

<station>
<station_name>Blackburne/Plymouth</station_name>
<latitude>16.75</latitude>
<longitude>-62.167</longitude>
<xml_url>http://weather.gov/xml/current_obs/TRPM.xml</xml_url>
</station>

解析后，我将这些数据存储在Station对象中，该对象实现了可比较的距离排序（我可以使用经度和纬度计算）。

protected Void doInBackground(Void...params){
    ....

    Station station = null;

    double stationLatitude = 0;
    double stationLongitude = 0;
    String xml = null;
    double distance = 0;

    ArrayList<Station> data = new ArrayList<Station>();

    for (int i = 0; i < itemList.getLength();i++){
        currentItem = itemList.item(i);
        //Log.i("Current Item: ", "" + currentItem.getNodeName());
        itemChildren = currentItem.getChildNodes();

        //..creating object Station
        station = new Station();
        for (int j = 0; j < itemChildren.getLength(); j++){

            currentChild = itemChildren.item(j);

            if (currentChild.getNodeName().equalsIgnoreCase("latitude")){

                stationLatitude = Double.parseDouble(currentChild.getTextContent());

                //Log.i("Latitude: ", "" + stationLatitude);

                station.setLatitude(stationLatitude);

            } else if (currentChild.getNodeName().equalsIgnoreCase("longitude")){

                stationLongitude = Double.parseDouble(currentChild.getTextContent());

                //Log.i("Longitude: ", "" + stationLongitude);

                station.setLongitude(stationLongitude);

            } else if (currentChild.getNodeName().equalsIgnoreCase("xml_url")){

                xml = currentChild.getTextContent();

                // Log.i("XML: ", "" + xml);

                station.setUrl(xml);
            }

            //inadeqaute values after quitting if/else:
            Log.i("Latitude: ", "" + station.getLatitude());
            Log.i("Longitude: ", "" + station.getLongitude());

            distance = calcDistance(deviceLongitude, deviceLatitude, station.getLongitude(), station.getLatitude());

            station.setDistance(distance);

            data.add(station);

        }

    }
    Collections.sort(data);

    Log.i("Shortest distance", "" + data.get(0).getDistance());
} catch (Exception e) {
    e.printStackTrace();
}
return null;
}

所以问题是我得到的纬度和经度值不足（太多了，它们被存储在对象中）：

02-21 13:30:10.762 29803-29843/com.andro.location I/Latitude:: 0.0
02-21 13:30:10.762 29803-29843/com.andro.location I/Longitude:: 0.0
02-21 13:30:10.762 29803-29843/com.andro.location I/Latitude:: 0.0
02-21 13:30:10.762 29803-29843/com.andro.location I/Longitude:: 0.0
02-21 13:30:10.762 29803-29843/com.andro.location I/Latitude:: 17.117
02-21 13:30:10.772 29803-29843/com.andro.location I/Longitude:: 0.0
02-21 13:30:10.772 29803-29843/com.andro.location I/Latitude:: 17.117
02-21 13:30:10.772 29803-29843/com.andro.location I/Longitude:: 0.0
02-21 13:30:10.772 29803-29843/com.andro.location I/Latitude:: 17.117
02-21 13:30:10.772 29803-29843/com.andro.location I/Longitude:: -61.783
02-21 13:30:10.772 29803-29843/com.andro.location I/Latitude:: 17.117
02-21 13:30:10.772 29803-29843/com.andro.location I/Latitude:: 17.117
02-21 13:30:10.772 29803-29843/com.andro.location I/Longitude:: -61.783
02-21 13:30:10.772 29803-29843/com.andro.location I/Latitude:: 17.117
02-21 13:30:10.782 29803-29843/com.andro.location I/Latitude:: 0.0
02-21 13:30:10.782 29803-29843/com.andro.location I/Longitude:: 0.0
02-21 13:30:10.782 29803-29843/com.andro.location I/Latitude:: 0.0
02-21 13:30:10.782 29803-29843/com.andro.location I/Longitude:: 0.0
02-21 13:30:10.782 29803-29843/com.andro.location I/Latitude:: 0.0
02-21 13:30:10.782 29803-29843/com.andro.location I/Longitude:: 0.0

当涉及到排序：Collections.sort（数据）；我得到的比较方法违反了它的一般契约例外：/

编辑：添加桩号类别：

public class Station implements Comparable<Station> {

    public double getDistance() {
        return distance;
    }

    public void setDistance(double distance) {
        this.distance = distance;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public double getLongitude() {
        return longitude;
    }

    public void setLongitude(double longitude) {
        this.longitude = longitude;
    }

    public double getLatitude() {
        return latitude;
    }

    public void setLatitude(double latitude) {
        this.latitude = latitude;
    }

    double distance;
    String url;
    double longitude;
    double latitude;

    @Override
    public int compareTo(Station other) {

        int result = this.distance <= other.distance ? -1 : 1;
        return result;
    }


}

Answer 1

将compareTo方法更改为

@Override
public int compareTo(Station other) {

    return Double.compare(this.distance, other.distance)
}

感谢@Andreas给出了更干净的答案