随机圈JAVA

我正在尝试创建一个GUI，它将获取要绘制的圆圈数，并在随机位置/大小的drawPanel中绘制它们。 在我的actionListener上，当我尝试绘制圆圈时，它在我的drawOval上给了我红线

第一节课：

import java.awt.BorderLayout; import java.awt.Color; import java.awt.Dimension; import java.awt.FlowLayout; import java.awt.Graphics; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.util.Random; import javax.swing.BorderFactory; import javax.swing.JButton; import javax.swing.JPanel; import javax.swing.JTextArea; /** * * @author Chris * */ public class CirclesPanel extends JPanel{ private JButton draw, clear; private JTextArea textArea; private JPanel panel, drawPanel, buttonPanel; private int count; /**constructor * builds the frame */ public CirclesPanel(){ //creates buttons and textArea draw = new JButton("Draw"); clear = new JButton("Clear"); textArea = new JTextArea(1,10); textArea.setBorder(BorderFactory.createTitledBorder("Circles")); //creats panel JPanel panel = new JPanel(); panel.setLayout(new BorderLayout()); setPreferredSize(new Dimension(620, 425)); //creates subpanel drawPanel JPanel drawPanel = new JPanel(); drawPanel.setPreferredSize(new Dimension(450,400)); drawPanel.setBackground(Color.BLACK); //creates subpanel buttonPanel JPanel buttonPanel = new JPanel(); buttonPanel.setLayout(new GridLayout(3,1)); //adds all the content to the frame add(panel); add(buttonPanel, BorderLayout.WEST); add(drawPanel, BorderLayout.EAST); buttonPanel.add(textArea); buttonPanel.add(draw); buttonPanel.add(clear); //reads if the draw button is clicked draw.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { count =Integer.parseInt(textArea.getText());//takes the count in repaint();//repaints the picture to add the circles } }); //reads if the clear button is clicked clear.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { count=0;//sets the count to 0 so nothing is painted repaint();//repaints the window } }); } /**Paint component * draws the random circles */ public void paintComponent(Graphics g) { Random generator = new Random(); int x, y, diameter; for(int i = 0; i < count; i++){ //loop that takes the count and does this "x" times g.setColor(Color.BLUE);//sets color to blue x = generator.nextInt(90);//random location for x y = generator.nextInt(90);//random location for y diameter = generator.nextInt(30);//random size g.fillOval(x, y, diameter, diameter);//draws the circle } } } 

二等

 import javax.swing.JFrame; public class Circles { public static void main(String[]args){ JFrame frame = new JFrame("Cicles HW9"); frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE); frame.getContentPane().add(new CirclesPanel()); frame.pack(); frame.setVisible(true); } } 

Answer 1

所以在你，我做了一点补充，首先，我把整个程序放在一个类（CIRLCES PANEL），如果你想使用第二个类，你可以使用它….问题来了，你的程序是不是为绘图读取ActionPerformed方法，意味着它没有找到按钮，现在我直接用你的按钮（DRAW）添加它，现在每当你点击按钮时，它会自动读取你的textArea值，并绘制你的界。 我把你的文字区域定为FINAL，所以你可以在任何地方使用……

现在您需要做的事情—–这个程序在整个框架上绘制圆圈，意味着不在您的绘图面板上，您需要设置值，因此它将绘制在您的绘图面板区域 – 您还需要为你的椭圆增添颜色，因为它会画出黑色的圆圈，你将无法看到……

而且我忘了提到你的一件事就是你的，你还需要为你明确的方法添加代码……

  import java.awt.BorderLayout; import java.awt.Color; import java.awt.Dimension; import java.awt.FlowLayout; import java.awt.Graphics; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.util.Random; import javax.swing.BorderFactory; import javax.swing.JButton; import javax.swing.JPanel; import javax.swing.JTextArea; public class CirclesPanel extends JPanel{ private JButton draw, clear; private JTextArea textArea; private JPanel panel, drawPanel, buttonPanel; private int count; public CirclesPanel(){ JButton draw = new JButton("Draw"); JButton clear = new JButton("Clear"); final JTextArea textArea = new JTextArea(1,10); textArea.setBorder(BorderFactory.createTitledBorder("Circles")); JPanel panel = new JPanel(); panel.setLayout(new BorderLayout()); setPreferredSize(new Dimension(620, 425)); JPanel drawPanel = new JPanel(); drawPanel.setPreferredSize(new Dimension(450,400)); drawPanel.setBackground(Color.BLACK); JPanel buttonPanel = new JPanel(); buttonPanel.setLayout(new GridLayout(3,1)); add(panel); add(buttonPanel, BorderLayout.WEST); add(drawPanel, BorderLayout.EAST); buttonPanel.add(textArea); buttonPanel.add(draw); buttonPanel.add(clear); draw.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { count =Integer.parseInt(textArea.getText()); repaint(); } }); } public void paintComponent(Graphics g) { Random generator = new Random(); int x, y, diameter; for(int i = 0; i < count; i++){ x = generator.nextInt(90); y = generator.nextInt(90); diameter = generator.nextInt(30); g.drawOval(x, y, diameter, diameter); } } } 

Answer 2

你想要做的是在点击按钮时在drawPanel上绘制一些随机圆圈 。 我给你写了一个简化版本来展示它是如何工作的。

我只保留drawButton和paintPanel以保持简单。

 public class PaintFrame extends JFrame { private JPanel content = new JPanel(); private JButton drawButton = new JButton("Draw"); private PaintPanel paintPanel = new PaintPanel(); public PaintFrame() { getContentPane().add(content); content.setLayout(new BorderLayout()); drawButton.setSize(100, 500); drawButton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { // drawButton is fired, repaint the paintPanel paintPanel.repaint(); } }); content.add(drawButton, BorderLayout.WEST); content.add(paintPanel, BorderLayout.CENTER); } } 

您需要一个新的类来扩展JPanel并覆盖paintComponent方法来为您执行绘制作业。 这可以确保您在面板上绘图 。

 class PaintPanel extends JPanel { public PaintPanel() { setSize(500, 500); setBackground(Color.BLACK); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); Random random = new Random(); g.setColor(Color.WHITE); // draw 5 random circles int count = 5; for (int i = 0; i < count; i++) { g.drawOval(random.nextInt(250), random.nextInt(250), random.nextInt(250), random.nextInt(250)); } } } 

主要课程

 public class DrawMain { public static void main(String[] args) { JFrame frame = new PaintFrame(); frame.setDefaultCloseOperation(PaintFrame.EXIT_ON_CLOSE); frame.setSize(600, 500); frame.setVisible(true); } }