Question

好吧我正在使用java swing编程GUI，我一直在使用一些旧的代码来创建一个移动的方块，但是现在我必须使用切换按钮来使一些形状出现并从窗口中消失。我的程序应该有4个不同的切换按钮（目前有3个），每个按钮都有一个特定的用途：名称将在屏幕中央显示我的名字，矩形将在屏幕的右下方显示一个矩形，椭圆形也会在右下方显示一个椭圆形。我试图使用一系列布尔来指示出现哪种形状，但由于某种原因，每个按钮只会切换矩形，我不知道为什么。有什么我做错了导致所有按钮做同样的事情？到目前为止，这是我的代码。第一个是我的paintPanel：

 import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class PaintPanel extends JPanel
{
    private static Color[] colors =
        { Color.RED, Color.BLACK, Color.PINK, Color.ORANGE };
    private int colorNumber = 0;

    private int shape = 0;

    private int x = 0;
    private int y = 0;

    private int width = 100;
    private int height = 100;
    private String display = " ";
    private String none = " ";

    private int dx = 2;
    private int dy = 2;

    private boolean rectangle = true;
    private boolean oval= true;
    private boolean Name = true;
    private boolean special = true;

    private String displayString = "hello";

    private boolean isStarted = true;

    /*public void update()
    {
        if (isStarted) 
        {
            x += dx;
            y += dy;
        }
        //dx ++;
        //dy ++;

        if (y + height > getHeight())
        {
            dy = -Math.abs(dy);
            shape++;
            colorNumber = (colorNumber+1)%colors.length;
        }
        else if (y < 0)
        {
            dy = Math.abs(dy);
            shape++;
            colorNumber = (colorNumber+1)%colors.length;
        }

        if (x + width > getWidth())
        {
            dx = -Math.abs(dx);
            shape++;
            colorNumber = (colorNumber+1)%colors.length;
        }
        else if (x < 0)
        {
            dx = Math.abs(dx);
            shape++;
            colorNumber = (colorNumber+1)%colors.length;
        }

    }*/
    public void input()
    {
        System.out.print("Button");
    }

    public void changeColor()
    {
        colorNumber = (colorNumber+1) % colors.length;
    }

    /*public void startStop()
    {
        //if (isStarted == true) isStarted = false;
        //else isStarted = true;

        isStarted = !isStarted;
    }
    */

    public void setDisplayText(String dt)
    {
        displayString = dt;
    }


    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        int w = getWidth();
        int h = getHeight();

        int textx = x+w/2;
        int texty = y+h/2;

            FontMetrics fm = g.getFontMetrics();
            int texth = fm.getHeight();
            int textw = fm.stringWidth(display);

            textx -= textw/2;
            texty += texth/2;
            texty -= 5; 
        if(Name == true)
        {
            g.setColor(Color.BLACK);
            g.drawString(display, textx, texty);
            Name = false;
        }
        else if(Name == false)
        {
            g.drawString(none, textx, texty);
            Name = true;
        }
        if (oval == true)
        {
            g.setColor(Color.CYAN);
            g.fillOval((5*w)/8, (5*h)/8, w/4, h/4);
            oval = false;
        }
        else if(oval == false)
        {
            g.setColor(Color.WHITE);
            g.fillOval((5*w)/8, (5*h)/8, w/4, h/4);
            oval = true;
        }
        if(rectangle == true)
        {
            g.setColor(Color.PINK);
            g.fillRect(w/2, h/2, w/2, h/2);
            rectangle = false;

        }
        else if(rectangle == false)
        {
            g.setColor(Color.WHITE);
            g.fillRect(w/2, h/2, w/2, h/2);
            rectangle = true;
        }



        /*int w = getWidth();
        int h = getHeight();
        g.setColor(colors[colorNumber]);
        if (shape % 2 == 0) //g.fillOval(x, y, width, height);
        elseg.fillRect(x,y, width, height);
        */ 
        /*
        int textx = x+width/2;
        int texty = y+height/2;

        FontMetrics fm = g.getFontMetrics();
        int texth = fm.getHeight();
        int textw = fm.stringWidth(displayString);

        textx -= textw/2;
        texty += texth/2;
        texty -= 5;     

        g.setColor(colors[(colorNumber+1)%colors.length]);
        g.drawString(displayString, textx, texty);
        */
    }

}

无论注释出来的是什么，因为它将在稍后的特殊按钮中实现。这是我的主要课程：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class GuiTest extends JFrame 
    implements ActionListener
{
    private Timer frameTimer;
    private JToggleButton Name;
    private JToggleButton oval;
    private JToggleButton rectangle;
    //private JTextField theText;
    private PaintPanel paintPanel;

    public GuiTest()
    {
        setTitle("Servando Hernandez");
        setSize(500,500);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel topPanel = new JPanel();
        topPanel.setLayout(new GridLayout(1,4));

        Name = new JToggleButton("Name");
        Name.addActionListener(this);

        oval = new JToggleButton("Oval");
        oval.addActionListener(this);

        rectangle = new JToggleButton("Rectangle");
        rectangle.addActionListener(this);

        //theText = new JTextField("HI");
        //theText.addActionListener(this);


        topPanel.add(Name);
        topPanel.add(oval);
        topPanel.add(rectangle);
        //topPanel.add(theText);

        Container contentPane = getContentPane();
        contentPane.setLayout(new BorderLayout());
        contentPane.add(topPanel, BorderLayout.SOUTH);

        paintPanel = new PaintPanel();
        contentPane.add(paintPanel, BorderLayout.CENTER);

        //frameTimer = new Timer(50, this);
        //frameTimer.start();
    }

    public void actionPerformed(ActionEvent e)
    {
        //System.out.println("Action performed");
        if (e.getSource() == oval)      
        {
            paintPanel.input();
        }
        /*else if (e.getSource() == frameTimer)
        {
            paintPanel.update();
        }*/
         if (e.getSource() == rectangle)
        {
            paintPanel.input();
        }
         if (e.getSource() == oval)
        {
            //System.out.println("start/stop");
            paintPanel.input();
        }
         if (e.getSource() == Name)
        {
            paintPanel.input();
            String text = e.getActionCommand();
            paintPanel.setDisplayText("Servando Hernandez");
            //System.out.println(text);
        }

        repaint();
    }

    public static void main(String[] args)
    {
        GuiTest gui = new GuiTest();
        gui.setVisible(true);

    }
}

Answer 1

无论被注释出来的是什么，因为它将在稍后实现一个特殊的按钮。

好吧，不要在问题中包含代码。代码与问题无关，我们不想浪费时间阅读或猜测它为什么存在？

private boolean Name = true;

为什么变量名称大写？其他变量都不以大写字母开头（这是正确的）。保持一致!!!

    if(Name == true)
    {
        g.setColor(Color.BLACK);
        g.drawString(display, textx, texty);
        Name = false;
    }
    else if(Name == false)
    {
        g.drawString(none, textx, texty);
        Name = true;
    }

你正在使if语句复杂化。如果布尔变量不为true，则为false。只需使用：

    if(name == true)
    //if(name) // even simpler, you don't need the "== true"
    {
        g.setColor(Color.BLACK);
        g.drawString(display, textx, texty);
    }
    else 
    {
        g.drawString(none, textx, texty);
    }

我不明白你的ActionListener代码。您点击的按钮始终执行paintPanel.input()无关紧要。

请参阅下面的编辑，了解代码应该是什么。

使用这些建议整理代码。如果您仍需要更多帮助，请发布展示问题的正确SSCCE。

编辑：

您需要向PaintPanel类添加属性。例如：

public void setOval(Boolean oval)
{
    this.oval = oval;
    repaint();
}

现在，在ActionListener中，您的代码将是：

if (e.getSource() == oval)
{
    paintPanel.setOval( oval.isSelected();
}

如何让每个切换按钮执行不同的操作？

1 个答案: