java JMapViewer，绘制到OSM并避免双重调用MouseClick事件

Question

假设Map3是以下类：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.JPanel;
import org.openstreetmap.gui.jmapviewer.Coordinate;
import org.openstreetmap.gui.jmapviewer.DefaultMapController;
import org.openstreetmap.gui.jmapviewer.JMapViewer;
import org.openstreetmap.gui.jmapviewer.MapPolygonImpl;


public class Map3 {

    private JPanel p;
    private JMapViewer map;
    private double lat, lon;

    public Map3() 
    {
            p = new JPanel();
            map = new JMapViewer();
            p.setLayout(new BorderLayout());

            new DefaultMapController(map) {
                @Override
                public void mouseClicked(MouseEvent e) {
                            Point p = e.getPoint();
                            lat = map.getPosition(p).getLat();
                            lon = map.getPosition(p).getLon();
                }
                //Where to locate the method ????
                protected void paintComponent(Graphics g){

                            Coordinate c1= new Coordinate(lat,lon),c2= new Coordinate(lat+10,lon+10);  //Draw the line

                            List<Coordinate> route = new ArrayList<Coordinate>(Arrays.asList(c1, c2, c1));
                            map.addMapPolygon(new MapPolygonImpl(route));
                        }   
            };

            p.add(map);
            p.setVisible(true);
    }


  public JPanel getJPanel() {return p;}
}

要避免鼠标侦听器的双重调用，请参见问题

JMapViewer, MouseListener called 2 times

该类不是直接从JMapViewer派生的。使用鼠标点击，我得到了两个坐标[lat，lon]，将用于绘制由P1，P2给出的线，其中P1=[lat，lon]，P2=[lat+10，lon+10]

我不确定方法paintComponent（）应该放在哪里，以便能够向OSM映射添加一些图形

public class TEST
{
    public static void main (String [] args)
    {
            JFrame jf = new JFrame();
            jf.setSize(800, 600);
            Map3 p = new Map3();
            jf.add(p.getJPanel()); 
            jf.setVisible(true);
    }
}

当前版本工作不正常，未调用paintComponent（）

谢谢你的帮助

Answer 1

已找到以下解决方案：

import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import javax.swing.JFrame;
import org.openstreetmap.gui.jmapviewer.Coordinate;
import org.openstreetmap.gui.jmapviewer.DefaultMapController;
import org.openstreetmap.gui.jmapviewer.JMapViewer;
import org.openstreetmap.gui.jmapviewer.MapPolygonImpl;

public class Map3 extends JMapViewer{
private double lat, lon;

public Map3() 
{
   new DefaultMapController(this) {
        public void mouseClicked(MouseEvent e) {
            System.out.println(e.getPoint());
            Point  p = e.getPoint();
            lat = map.getPosition(p).getLat();
            lon = map.getPosition(p).getLon();
        }};
  }

protected void paintComponent(Graphics g){
    super.paintComponent(g);
    Coordinate c1= new Coordinate(lat,lon),c2= new Coordinate(lat+10,lon+10);
    List<Coordinate> route = new ArrayList<Coordinate>(Arrays.asList(c1, c2, c1));
    this.addMapPolygon(new MapPolygonImpl(route));
}   

public static void main (String [] args){
            JFrame jf = new JFrame();
            jf.setSize(800, 600);
            Map3 m= new Map3();
            jf.add(m);
            jf.setVisible(true);
    }
}

主要的想法是取代

 addMouseListener(new DefaultMapController(this) {
        public void mouseClicked(MouseEvent e){
            System.out.println(e.getPoint());
            Point  p = e.getPoint();
            lat = map.getPosition(p).getLat();
            lon = map.getPosition(p).getLon();
        });

用下面的结构

new DefaultMapController(this) {
        public void mouseClicked(MouseEvent e) {
            System.out.println(e.getPoint());
            Point  p = e.getPoint();
            lat = map.getPosition(p).getLat();
            lon = map.getPosition(p).getLon();
        }};

在这种情况下，Map3可能来自JMapViewer。希望有帮助：-）

Answer 2

p.add(map);

您正在将“地图”添加到面板中。因此，您需要重写JMapViewwer类的paintComponent()方法

无论何时重写类的方法，都应使用：

@Override
protected void paintComponent(Graphics g)
...

如果不正确地重写了一个方法，就会出现编译错误

但是，在您的情况下，甚至不应该重写paintComponent（）方法。这种方法只适用于绘画。它不用于添加新的多边形对象。也许代码应该在mousePressed（）逻辑中