MouseDragged＆amp; MouseMoved无法在Java Applet中运行

时间：2013-06-05 01:09:41

标签： java swing event-handling mouseevent japplet

我正在为我正在创建的游戏制作地图生成程序，所以我试图能够使用我的鼠标修改地图上的各个图块。我已经成功实现了点击图块并更改其值（从4路图块到2行图块）的功能，但是我无法使用mouseDragged工作。根据Java文档，我已经将mouseDragged接口正确实现到我的MouseEventHandler中，但是当我拖动鼠标并移动我的鼠标时，这些事件都没有跳过并扔掉我给他们扔的println文本现在。如果有人能说清楚为什么这对我不起作用，我会喜欢的。谢谢！

一个侧面问题：如果有人有任何更好的方法来尝试生成这样的地图，或任何（可能是比我做的更好）其他检测单个鼠标的方法压在瓷砖上，我很乐意听到它。这只是我第一次使用这种东西，所以我很缺乏经验，并且会喜欢一些建议。

至于代码本身：

文件1：OneQuestMapgen.java 

package OneQuestMapgen;

import java.awt.Graphics;
import java.util.ArrayList;
import javax.swing.*;

import tiles.Tile;
import tiles.TileSet;

public class OneQuestMapgen extends JApplet{

    /**
     * 
     */

    public static OneQuestMapgen instance;

    ArrayList<ArrayList<Tile>> map = new ArrayList<ArrayList<Tile>>();
    TileSet tileSet = new TileSet();

    public void init(){
        this.setSize(950,600);
    }

    public void start(){
        this.addMouseListener(new MouseEventListener(this));

        int tileSize = tileSet.get("grasslands")[1].getHeight();

        for (int i = 0; i < getHeight(); i += tileSize) {
            ArrayList<Tile> temp = new ArrayList<Tile>();
            for (int j = 0; j < getWidth(); j += tileSize) {
                temp.add(new Tile(j, i, tileSize, tileSet.get("grasslands")));
            }
            map.add(temp);
        }

    }

    public void paint(Graphics g){

        for (int i = 0; i < map.size(); i++){
            for(int j = 0; j < map.get(i).size(); j++){
                map.get(i).get(j).render(g);
            }               
        }
    }

    public void stop(){
    }

    public void destroy(){
    }

    public ArrayList<ArrayList<Tile>> getMap(){
        return map;
    }
}

文件2：MouseEventListener.java 

package OneQuestMapgen;

import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.util.ArrayList;

import tiles.Tile;

public class MouseEventListener implements MouseListener, MouseMotionListener {

    OneQuestMapgen instance;
    ArrayList<ArrayList<Tile>> map;

    public MouseEventListener(OneQuestMapgen instance) {
        this.instance = instance;
    }

    @Override
    public void mouseClicked(MouseEvent e) {
        System.out.println(e.getX() + " , " + e.getY());
        map = instance.getMap();
        for (int i = 0; i < map.size(); i++) {
            for (int j = 0; j < map.get(i).size(); j++)
                if (map.get(i).get(j).bounds(e)) {
                    map.get(i).get(j).onClicked(instance.getGraphics());
                }
        }   
    }

    @Override
    public void mouseEntered(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseExited(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mousePressed(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseReleased(MouseEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseDragged(MouseEvent arg0) {

        System.out.println("Mouse Dragged: " + arg0.getX() + " , " + arg0.getY());          
    }

    @Override
    public void mouseMoved(MouseEvent arg0) {
        // TODO Auto-generated method stub
        System.out.println("Mouse Moved: " + arg0.getX() + " , " + arg0.getY());

    }

}

文件3：Tile.java 

package tiles;

import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;

@SuppressWarnings("serial")
public class Tile extends Square {

    BufferedImage[] tiles;
    int tileValue = 0;

    public Tile (int x, int y, int size, BufferedImage[] tileSet){
        super(x,y,size);
        tiles = tileSet;
    }

    public void render(Graphics g) {

        g.drawImage(tiles[tileValue], getX(), getY(), getDimension(), getDimension(), null);        
    }

    public void onClicked(Graphics g) {
        tileValue++;
        System.out.println(tileValue);
        g.drawImage(tiles[tileValue], getX(), getY(), getDimension(), getDimension(), null);
    }

    public boolean bounds(MouseEvent e){
        if (e.getX() <= getX() + getDimension()  && e.getX() >= getX() && e.getY() <= getY() + getDimension() && e.getY() >= getY())
            return true;
        return false;
    }
}

文件4：TileSet.java 

package tiles;

import java.awt.image.BufferedImage;
import java.net.URL;
import java.util.concurrent.ConcurrentHashMap;

import javax.imageio.ImageIO;

public final class TileSet {

    ConcurrentHashMap<String, BufferedImage[]> container = new ConcurrentHashMap<String, BufferedImage[]>(11);
    BufferedImage[] grasslands = new BufferedImage[11];

    public TileSet(){

        boolean toAdd = true;

        try {   
            grasslands[0] = ImageIO.read(new URL("http://i675.photobucket.com/albums/vv118/va023/OneQuest/GrassBlank_zpse99de845.png"));
            grasslands[1] = ImageIO.read(new URL("http://i675.photobucket.com/albums/vv118/va023/OneQuest/4WayTile_zps49ebbeea.png"));
            grasslands[2] = ImageIO.read(new URL("http://i675.photobucket.com/albums/vv118/va023/OneQuest/LineHorizontal_zpsc7bd45d5.png"));
            grasslands[3] = ImageIO.read(new URL("http://i675.photobucket.com/albums/vv118/va023/OneQuest/LineVertical_zps9719b63f.png"));
            grasslands[4] = ImageIO.read(new URL("http://i675.photobucket.com/albums/vv118/va023/OneQuest/TShapeTop_zpsa4b2aaa1.png"))          
        }

        catch (Exception e) {
            System.out.println("Unable to load resources for Grasslands");
        }

        for (int i = 0; i < grasslands.length; i++)
            if (grasslands[i].getWidth() != grasslands[i].getHeight()) {
                System.out.println("Error, tiles are not square. Grasslands has not been added.");
                toAdd = false;
            }

        if (toAdd) {
            container.put("grasslands".toLowerCase(), grasslands);
        }
    }

    public BufferedImage[] get(String s) {
        return container.get(s.toLowerCase());
    }
}

文件5：Square.java 

package tiles;

import javax.swing.JLabel;

public abstract class Square extends JLabel{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    private int x;
    private int y;
    private int dimension;

    public Square(int x, int y, int dimension){

        this.x = x;
        this.y = y;
        this.dimension = dimension;
    }

    public int getX(){
        return x;
    }

    public int getY(){
        return y;
    }

    public int getDimension(){
        return dimension;
    }
}

注意：如果您希望能够将其全部从github中删除，我已在下面的项目中为我的github repo添加了一个链接：

网址：https://github.com/vagrawal1/OneQuestMapgen

HTTPS：https://github.com/vagrawal1/OneQuestMapgen.git

SSH：git@github.com：vagrawal1 / OneQuestMapgen.git

Git Read-Only：git：//github.com/vagrawal1/OneQuestMapgen.git

再次感谢您的帮助，感谢您花时间阅读本文。

1 个答案:

答案 0 :(得分：9)

您需要添加MouseMotionListener才能拖动工作。您只需添加一个MouseListener。

即，

public void start() {
  MouseEventListener myMouseEventListener = new MouseEventListener(this);
  addMouseListener(myMouseEventListener);
  addMouseMotionListener(myMouseEventListener);

  //this.addMouseListener(new MouseEventListener(this));

另外根据我的评论，Square类的getX（）和getY（）方法覆盖了JLabel的相同方法，如果你不小心这些并正确使用它们就会完全陷入困境组件在GUI中的位置。我自己，我竭尽全力避免压倒这些方法。如果覆盖不是你的意图，请考虑更改他们的名字。

此外，我倾向于mousePressed(...)优于mouseClicked(...)方法，因为即使您在按下鼠标后移动鼠标，前者也会对媒体做出回应。

编辑：另一个错误！您几乎永远不会通过调用组件上的getGraphics()来获取您的Graphics实例，因为返回的Graphics对象是渐渐消失的，很快就会变为null。相反，要么绘制一个显示在JComponent或JPanel paintComponent(...)中的BufferedImage，要么只绘制paintComponent(...)本身。

编辑2：为什么覆盖paint(...)？这对我来说似乎有点危险，特别是因为你没有调用超级方法，特别是因为没有必要做这种事情。

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