Java输入错误

Question

好吧，我放弃了。我担任 C++ 程序员已有几年，但我尝试学习 Java，因为它是一种流行语言。在我学习的过程中，我学到了很多东西，但最终我开始尝试并尝试使用输入系统，这样当我单击这个红色菱形多边形时，它就会变成绿色，但经过几天令人沮丧的日子后......什么也没有。我仍然只有一颗红钻。它可能很小，但我就是找不到它

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class Vici extends Applet
{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private Space castle;

    public Vici()
    {
        castle = new Space();
        castle.addMouseListener(new SpaceInput());
    }



    public void paint(Graphics g)
    {
        Graphics2D g2d = (Graphics2D)g;


        int width = getSize().width;
        int height = getSize().height;

        g2d.setColor(Color.BLACK);
        g2d.fillRect(0, 0,  width, height);


        castle.paint(g2d);


    }

    class SpaceInput implements MouseListener
    {

        public void mouseEntered(MouseEvent m) { }
        public void mouseExited(MouseEvent m) { }
        public void mouseReleased(MouseEvent m)
        {
            switch(m.getButton())
            {
                case MouseEvent.BUTTON1:
                    castle.setColor(Color.GREEN);
                    castle.repaint();
                    repaint();
            }
        }
        public void mouseClicked(MouseEvent m)
        {
            switch(m.getButton())
            {
                case MouseEvent.BUTTON1:
                    castle.setColor(Color.GREEN);
                    castle.repaint();
                    repaint();
            }
        }
        public void mousePressed(MouseEvent m)
        {
            switch(m.getButton())
            {
                case MouseEvent.BUTTON1:
                    castle.setColor(Color.GREEN);
                    castle.repaint();
                    repaint();
            }
        }
    }

}








import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;

public class Space extends Canvas 
{
    private Polygon poly;
    private Color c;
    private int[] polyX = { 0, 24, 0, -24 };
    private int[] polyY = { 24, 0, -24, 0 };

    public void init()
    {
        poly = new Polygon( polyX, polyY, polyX.length);
        c = Color.red;
    }

    Space()
    {
        init();
    }

    void setColor(Color c)
    {
        this.c = c;
    }

    public void paint(Graphics g)
    {       
        Graphics2D g2d = (Graphics2D)g;

        AffineTransform identity = new AffineTransform();

        g2d.setTransform(identity);

        g2d.translate(100, 100);

        g2d.setColor(c);
        g2d.fill(poly);
    }

    public void update( Graphics g )
    {
        paint( g );
    }
}

Answer 1

我摆脱了无关的“SpaceInput”类，并将鼠标监听器添加到小程序(而不是“城堡”)。一切顺利:)

public class Vici extends Applet implements MouseListener
{

    private static final long serialVersionUID = 1L;
    private Space castle;

    public Vici()
    {
        castle = new Space();
        // castle.addMouseListener(this);
        addMouseListener (this);
    }



    public void paint(Graphics g)
    {
        Graphics2D g2d = (Graphics2D)g;


        int width = getSize().width;
        int height = getSize().height;

        g2d.setColor(Color.BLACK);
        g2d.fillRect(0, 0,  width, height);


        castle.paint(g2d);


    }

    public void mouseEntered(MouseEvent m) {
System.out.println ("mouse entered...");
    }
    public void mouseExited(MouseEvent m) {
System.out.println ("mouse mouseExited...");            
    }
    public void mouseReleased(MouseEvent m)
    {
System.out.println ("mouse mouseReleased...");          
        switch(m.getButton())
        {
            case MouseEvent.BUTTON1:
                castle.setColor(Color.GREEN);
                castle.repaint();
                repaint();
        }
    }
    public void mouseClicked(MouseEvent m)
    {
System.out.println ("mouse mouseClicked...");           
        switch(m.getButton())
        {
            case MouseEvent.BUTTON1:
                castle.setColor(Color.GREEN);
                castle.repaint();
                repaint();
        }
    }

    public void mousePressed(MouseEvent m)
    {
System.out.println ("mouse mousePressed...");           
        switch(m.getButton())
        {
            case MouseEvent.BUTTON1:
                castle.setColor(Color.GREEN);
                castle.repaint();
                repaint();
        }
    }

}