Question

在Java中使用GUI时遇到了麻烦。我想写一个程序，要求我在屏幕中央画一个星星，但在它绘制它之前我想让它问我有多想让星星拥有武器。我制作的这段代码只是在没有任何其他东西的情况下绘制一颗星（http://i.imgur.com/JSsfuyt.png）

所以我必须修改它（也许是一些自定义类型的Scanner询问我的武器数量），但我在GUI和Java上并不擅长。你能帮助我吗？提前谢谢。

import java.awt.BasicStroke;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.geom.Path2D;

public class App extends Frame
{
    public static void main(String[] args)
    {
        new App();
    }

    public App()
    {
        setSize(540, 380);
        setVisible(true);
    }

    public void paint(Graphics g)
    {
        Graphics2D g2 = (Graphics2D) g; 
        g2.setStroke (new BasicStroke (15.0f)); 

        Rectangle r = getBounds(); 
        float width = 166; 
        float height = 166; 

        g2.translate( r.getWidth() / 2 - width/2, r.getHeight() / 2 - height/2); 

        Path2D star = new Path2D.Float (); 
        star.moveTo (width/5F, height-1); 
        star.lineTo (width/2F, 0); 
        star.lineTo (4*width/5F, height-1); 
        star.lineTo (0, 2*height/5F); 
        star.lineTo (width-1, 2*height/5F); 
        star.closePath (); 
        g2.draw (star); 
        g2.fill (star);
    }
}

Answer 1

你需要阅读布局管理器和文档监听器看看这段代码，它使用了一个空布局管理器，这是不推荐的，但在这里工作正常。为了从文本框中获取值，您需要将字段添加到drawpanel并从insertUpdate事件中设置它们


    package star;

    import java.awt.*;
    import java.awt.geom.Path2D;
    import java.util.Random;

    import javax.swing.*;
    import javax.swing.event.DocumentEvent;
    import javax.swing.event.DocumentListener;

    public class StarApp {
    public static void main(String[] args) {
        new StarApp();
    }
    StarFrame sf = new StarFrame();
    public StarApp() {
    }

    public class StarFrame extends JFrame implements DocumentListener {

        StarDrawPanel drawpanel = new StarDrawPanel();
        StarInputPanel inputpanel = new StarInputPanel();

        public StarFrame () {
            inputpanel.input.getDocument().addDocumentListener(this);   
            this.setLayout(null);
            this.add(inputpanel);
            this.add(drawpanel);
            drawpanel.setSize(540, 360);
            setSize(540, 380);
            inputpanel.setSize(50,30);
            setVisible(true);
        }
        public void insertUpdate(DocumentEvent arg0) {          
            drawpanel.repaint();
        }
        public void changedUpdate(DocumentEvent arg0) {
        }
        public void removeUpdate(DocumentEvent arg0) {
        }
    }

    public class StarDrawPanel extends JPanel {

        Random rand = new Random();
        public void paint(Graphics g)
        {
            Graphics2D g2 = (Graphics2D) g; 
            g2.setStroke (new BasicStroke (15.0f)); 
            Rectangle r = getBounds(); 
            float width = 166; 
            float height = 166; 
            g2.translate( r.getWidth() / 2 - width/2, r.getHeight() / 2 - height/2); 
            Path2D star = new Path2D.Float (); 
            star.moveTo (width/5F, height-1); 
            star.lineTo (width/2F, 0); 
            star.lineTo (4*width/5F, height-1); 
            star.lineTo (0, 2*height/5F); 
            star.lineTo (width-1, 2*height/5F); 
            star.closePath (); 
            g2.draw (star); 
            float rc = rand.nextFloat();
            float gc = rand.nextFloat();
            float bc = rand.nextFloat();
            Color randomColor = new Color(rc, gc, bc);
            g2.setPaint(randomColor);
            g2.fill (star);
        }
    }

    public class StarInputPanel extends JPanel {
        public JTextField input = new JTextField(4);
        public StarInputPanel() {
            this.add(input);
        }
    }

    }

如何在Java GUI中绘制一个星？

1 个答案: