在Click基礎上繪製2D圖形對象

Question

以下是我的代碼如下。它在執行時繪製三角形。我想對它做一些改變。 更改爲

執行時會有1個三角形。但如果我在三角形1內點擊，則會畫出其他三角形。否則不畫。

我試圖與變化做g2d.draw(triangle2);

但它有問題。它只是不顯示三角形，但將其繪製爲隱藏。

public class Triangle_shape extends JFrame implements ActionListener { 
    public static int x=0; 
    public static JButton btnSubmit = new JButton("Submit"); 
    public static JButton change = new JButton("Change"); 
    public Triangle_shape(){ 
    } 
    public static void main(String[] args) { 

    TrianglePanel t= new TrianglePanel(); 
    ClickListener cl= new ClickListener(); 
    JFrame frame = new JFrame(); 
    final int FRAME_WIDTH = 500; 
    final int FRAME_HEIGHT = 500; 
    btnSubmit.addActionListener(cl); 
    frame.setSize (FRAME_WIDTH, FRAME_HEIGHT);   
    frame.setLayout(new BorderLayout()); 
    frame.add(new TrianglePanel(), BorderLayout.CENTER); 
    frame.add(btnSubmit, BorderLayout.PAGE_END); 
    frame.add(change, BorderLayout.LINE_END); 
    frame.pack(); 
    frame.repaint(); 
    frame.setTitle("A Test Frame");    
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    frame.setVisible(true); 
    } 

    public static class TrianglePanel extends JPanel implements MouseListener{ 
     private Polygon triangle,triangle2; 

     public TrianglePanel(){ 
      //Create triangle 
      System.out.println("From Draw "+x); 
      triangle = new Polygon(); 
      triangle.addPoint(150, 200); 
      triangle.addPoint(100, 100); 
      triangle.addPoint(200, 100); 
      triangle2 = new Polygon(); 
      triangle2.addPoint(200, 300); 
      triangle2.addPoint(200, 200); 
      triangle2.addPoint(300, 200); 
      //Add mouse Listener 
      addMouseListener(this); 
      //Set size to make sure that the whole triangle is shown 
      setPreferredSize(new Dimension(300, 300)); 
     } 

     /** Draws the triangle as this frame's painting */ 

     public void paintComponent(Graphics g){ 
      Graphics2D g2d = (Graphics2D)g; 
      System.out.println("From Graphics "+x); 
      g2d.draw(triangle); 
      g2d.draw(triangle2); 
     } 

     //Required methods for MouseListener, though the only one you care about is click 
     public void mousePressed(MouseEvent e) {} 
     public void mouseReleased(MouseEvent e) {} 
     public void mouseEntered(MouseEvent e) {} 
     public void mouseExited(MouseEvent e) {} 

     /** Called whenever the mouse clicks. */ 
     public void mouseClicked(MouseEvent e) { 
      x++; 
      Point p = e.getPoint(); 
      if(triangle.contains(p) ) 
       System.out.println("1"); 
      else if (triangle2.contains(p)) 
      {  System.out.println("2"); 
      } 
      else 
      { 
       System.out.println("Trianglhhhhhhhhhhhhhhhhhhpoint"); 
      x--;} 
     }   
    } 
    private static class ClickListener implements ActionListener { 
    private int clickCount = 0; 
    @Override 
    public void actionPerformed(ActionEvent e) { 
     if (e.getSource() == btnSubmit) { 
     clickCount++; 
     if (clickCount == 1) 
      btnSubmit.setText("clicked!"); 
     else 
     btnSubmit.setText("Inside Triangle " + x + " times!"); 
     } 
     else { 
      //JOptionPane.showMessageDialog(MainClass.this, "You must click at least once!", 
      btnSubmit.setText("Error " + clickCount + " times!");   
     } 

     } 
    } 
} 

Answer 1

嘗試下面的代碼，從你自己的代碼創建了一個樣本。

import javax.swing.*; 
    import java.awt.*; 
    import java.awt.event.MouseEvent; 
    import java.awt.event.MouseListener; 
    public class MyTriangle{ 
    static JFrame frame = new JFrame(); 
    public static void main(String[] args) 
    { 
    frame.setSize(1000, 1500); 
    frame.setTitle("Triangle Draw"); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

    //add panel to frame and make it visible 
    Polygon triangle1 = new Polygon(); 
    triangle1.addPoint(100, 500); // first 
    triangle1.addPoint(600, 500);//last 
    triangle1.addPoint(350, 300);//middel 
    addTriangle(new Triangle(triangle1)); 
    frame.setVisible(true); 
} 

public static void addTriangle(Triangle triangle1) 
{ 
    frame.add(triangle1); 
} 
static class Triangle extends JPanel implements MouseListener{ 
    private Polygon triangle; 

    public Triangle(Polygon triangle) 
    { 
     this.triangle = triangle; 

     addMouseListener(this); 
    } 

    public void paintComponent(Graphics g){ 
     Graphics2D g2d = (Graphics2D)g; 
     g2d.draw(triangle); 

    } 

    @Override 
    public void mouseClicked(MouseEvent e) { 
     Point p = e.getPoint(); 
     if(triangle.contains(p)) 
     { 
      Polygon triangle2 = new Polygon(); 
      triangle2.addPoint(200, 300); 
      triangle2.addPoint(200, 200); 
      triangle2.addPoint(300, 200); 
      MyTriangle.addTriangle(new Triangle(triangle2)); 
      Graphics2D g2d = (Graphics2D)this.getGraphics(); 
      g2d.draw(triangle2); 
     } 
    } 


} 

}