为什么我的MouseListener不按顺序递增变量？ [英] Why does my MouseListener not increment a variable in sequential order?

问题描述

在我的类 X 中，我扩展了 JPanel 并实现了 MouseListener ， MouseMotionListener

  int numPoints = 0; 
点控制点[] =新点[10]; 
 
 public void MousePressed（MouseEvent arg0）{
 if（numPoints< 5）
 controlPoints [numPoints] = arg0.getPoint（）; 
 numPoints ++; 
} 
  

* 当我System.out.println（numPoints）; *

在3次CLICKS后输出;

• 0


• 0


• 2
>

• 2


• 3


• 3
$

• 5 b $ b
  
  

  为什么不通过1，2，3增加??? b / b>
  
  

  输出
  $ b

  
  
  • 1
  
  
  • 2
  
  
  
  
  

  ***我会在必要时提供更多资讯。

  
  
  

  ---

  
  
  

  
  

  感谢您的回复。这里是完整编辑的javacode。这个问题对我来说依然没有解决。我期待着新的想法和更正。提前致谢

  
  

  
  
  

    package work2014.java.all; 
   
   java.awt。*; 
   import java.awt.event。* 
   import java.util.ArrayList; 
   
   import javax.swing。*; 
   
   
   class jdrawPanel扩展JPanel实现MouseListener，MouseMotionListener，ActionListener 
   {
   
   
  图形g; 
   boolean paint = false，edit = false; 
  点d; 
   point curvePoints [] = new Point [100]; 
   Point [] controlPoints = new Point [99]; 
   int n = 99，i = 3; 
   private int numPoints = 0; 
   
   
   public void paintComponent（Graphics g）{
   addMouseListener（this）; 
   addMouseMotionListener（this）; 
   
   super.paintComponent（g）; 
   if（numPoints> = 0& numPoints< controlPoints.length）
   Dot（numPoints，controlPoints，g）; 
   if（paint == true&& numPoints> = 3）{
   drawBezier（n，i，controlPoints，g）; 
  } 
   
   this.requestFocus（）; 
   
   
   $ b public void Dot（int numPoints，Point controlPoints []，Graphics g）{
   
   draw red dot 
  } 
   
   $ b $ public void drawBezier（int n，int i，Point controlPoints []，Graphics g）
   {
   draw spline 
   
  } / / End drawBezier 
   
   
   
   $ b @Override 
   public void mouseMoved（MouseEvent arg0）{
   Point p = arg0.getPoint（）; 
   if（equalPoint（p）== p）
   
   setCursor（Cursor.getPredefinedCursor（Cursor.HAND_CURSOR））; 
   else 
   setCursor（Cursor.getDefaultCursor（））; 
   
   
   
   
   $ b @Override 
   public void mousePressed（MouseEvent arg0）{
   paint = true; 
   Point d = arg0.getPoint（）; 
   
   if（numPoints< = 10）{
   controlPoints [numPoints] = d; 
   numPoints ++; 
   System.out.println（numPoints）; 
  } 
   repaint（）; 
   
  } 
   
   
   
  } 
   
  类Oving5_Frame扩展JFrame 
   {public Oving5_Frame（）
   {setTitle（Hello draW v2）; 
   setSize（600，600）; 
   $ b $ addWindowListener（new WindowAdapter（）
   {public void windowClosing（WindowEvent e）
   {System.exit（0）; 
  } 
  }）; 
   
  容器contentPane = getContentPane（）; 
   contentPane.setLayout（new BorderLayout（））; 
   contentPane.add（新的jdrawPanel，BorderLayout.CENTER）; 
   contentPane.add（class_menu（），BorderLayout.NORTH）; 
   
   
   
   
   
   public class Oving5_launch 
   {
   public static void main（String [] args）
   {
   JFrame frame = new Oving5_Frame（）; 
   frame.show（）; 
  } 
   
   
   
  } 
    

  
  

  解决方案

  您应该检查事件对象的属性以查看您正在响应的事件类型。你很可能需要 if（arg0.getID（）== MouseEvent.MOUSE_CLICKED）在那里。

  
  

  In my Class X I have extended JPanel and implemented MouseListener, MouseMotionListener

  int numPoints = 0;
  Point controlPoints[] = new Point[10];
  
  public void MousePressed (MouseEvent arg0) {
    if (numPoints < 5) 
      controlPoints[numPoints] = arg0.getPoint();
    numPoints++;
  }
  

  *When I System.out.println(numPoints); *

  output after 3 CLICKS;

  • 0
  • 0
  • 2
  • 2
  • 3
  • 3
  • 5

  WHY Does it not INCREMENT by 1, 2 ,3 ???

  output (for numPoints) (first mouseclick)

  • 1
  • 2

  ***I will provide more information if necessary.

  ---

  Thanks for the response. Here is the full edited javacode. The problem is still unsolved for me. I look forward to new ideas and corrections. Thanks in advance

  package work2014.java.all;
  
  java.awt.*;
  import java.awt.event.*
  import java.util.ArrayList;
  
  import javax.swing.*;
  
  
   class jdrawPanel extends JPanel implements MouseListener, MouseMotionListener,            ActionListener
   {  
  
  
  Graphics g;
  boolean paint = false, edit = false;
  Point d;
  Point curvePoints[]= new Point[100];
  Point[] controlPoints = new Point[99];
  int n = 99, i = 3;
  private int numPoints = 0;
  
  
  public void paintComponent(Graphics g){
      addMouseListener(this);
      addMouseMotionListener(this);
  
      super.paintComponent(g);
        if(numPoints >= 0 && numPoints < controlPoints.length)
          Dot(numPoints,controlPoints,g);
           if(paint == true && numPoints >= 3){
              drawBezier(n, i, controlPoints, g);
      }
  
      this.requestFocus();
  }
  
  
  public void Dot(int numPoints, Point controlPoints[], Graphics g){
  
      draw red dot
  }
  
  
  public void drawBezier(int n, int i, Point controlPoints[], Graphics g)
  {
      draw spline
  
  } // End drawBezier
  
  
  
  
  @Override
  public void mouseMoved(MouseEvent arg0) {
      Point p = arg0.getPoint(); 
      if (equalPoint(p) == p)
  
          setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
      else
          setCursor(Cursor.getDefaultCursor());
  
  }
  
  
  
  @Override
  public void mousePressed(MouseEvent arg0) {
      paint = true;
      Point d = arg0.getPoint();
  
      if(numPoints <= 10) {
          controlPoints[numPoints] = d;
                      numPoints++;
          System.out.println(numPoints);
      }
      repaint();
  
  }
  
  
  
  }
  
  class Oving5_Frame extends JFrame
  {  public Oving5_Frame()
   {  setTitle("Hello draW v2");
      setSize(600, 600);
  
    addWindowListener(new WindowAdapter()
       {  public void windowClosing(WindowEvent e)
          {  System.exit(0);
          }
       } );
  
    Container contentPane = getContentPane();
    contentPane.setLayout(new BorderLayout());
    contentPane.add(new jdrawPanel, BorderLayout.CENTER);
    contentPane.add(class_menu(), BorderLayout.NORTH);
  }
  
  
  
  
      public class Oving5_launch
      { 
       public static void main(String[] args)
      {  
    JFrame frame = new Oving5_Frame();
       frame.show();
      }
  
  
  
  }
  

  解决方案

  You should probably be checking the properties of the event object to see what type of event you are responding to. You most likely need if (arg0.getID() == MouseEvent.MOUSE_CLICKED) in there somewhere.

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