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大家好！Java - 重绘方法repaint（）不调用paintComponent（）方法

我有一个奇怪的问题，这与所有这些油漆“东西”有关。我创建了一个可以绘制高程曲线的小SWING应用程序（http://en.wikipedia.org/wiki/Dragon_curve）。我有3个班在我的项目：

DragonData - 有一切什么是有关计算和存储龙点，
GUI - 用户界面窗口，
点 - 类指定的单点，

现在好了：我有一个JPanel，我想绘制点和一个点击按钮开始计算点accordinates和绘图龙。

我的问题是：为什么它不工作？我为此JPanel创建了覆盖方法paintComponent，并在'buttonDrawActionPerformed'方法中调用它。我做错了什么？

有一个链接到我的项目：http://www73.zippyshare.com/v/9630962/file.html

代码

Point.java

public class Point { 

    private double x; 
    private double y; 

    public Point(double x, double y) { 
     this.x = x; 
     this.y = y; 
    } 

    public double getX() { 
     return x; 
    } 

    public void setX(double x) { 
     this.x = x; 
    } 

    public double getY() { 
     return y; 
    } 

    public void setY(double y) { 
     this.y = y; 
    } 
}

DragonData.java

import java.util.ArrayList; 

public class DragonData { 

    private static final int RATE = 500; 
    private static ArrayList<Point> dragonPoints = null; 

    public static void generatePoints(double x, double y, int iter, 
      int shiftX, int shiftY){ // ### TYP double 

     dragonPoints = new ArrayList<Point>(); 

     for(int i = 0 ; i < iter ; i++){ 

      int option = (int)(Math.random() * 2); 

      switch(option){ 

       case 0: 
        x = -0.4 * x - 1; 
        y = -0.4 * y + 0.1; //### !!! ### - aktualizujemy wartosc zmiennej 
        break; 

       case 1: 
        x = 0.76 * x - 0.4 * y; 
        y = 0.4 * x + 0.76 * y; 
        break; 
      } 

      dragonPoints.add(new Point(x, y)); 
     }; 

     calibrateCoordinates(); 
     filterPoints(shiftX, shiftY); 
    } 

    private static void calibrateCoordinates(){ 

     int pointsCount = dragonPoints.size(); 

     for(int i = 0 ; i < pointsCount ; i++){ 

      double scaledX = dragonPoints.get(i).getX() * RATE; 
      double scaledY = dragonPoints.get(i).getY() * RATE; 

      dragonPoints.get(i).setX(scaledX); 
      dragonPoints.get(i).setY(scaledY); 
     } 
    } 

    private static void filterPoints(int shiftX, int shiftY){ 

     int pointsCount = dragonPoints.size(); 
     ArrayList<Point> choosen = new ArrayList<Point>(); 

     for(int i = 0 ; i < pointsCount ; i++){ 

      double x = dragonPoints.get(i).getX() + shiftX; 
      double y = dragonPoints.get(i).getY() + shiftY; 

      if((x > 0 && x < 800) && (y > 0 && y < 600)) 
       choosen.add(new Point(x,y)); 
     } 

     dragonPoints.clear(); 
     dragonPoints.addAll(choosen); 

     System.out.println("New points count: " + dragonPoints.size()); 

    } 

    public static ArrayList<Point> getDragonPoints() { 
     return dragonPoints; 
    } 

}

一开始你创建overrided paintComponent(...)您的面板GUI.java

import java.awt.Graphics; 
import java.util.ArrayList; 

public class GUI extends javax.swing.JFrame { 

    /** 
    * Creates new form GUI 
    */ 
    public GUI() { 
     initComponents(); 
    } 

    /** 
    * This method is called from within the constructor to initialize the form. 
    * WARNING: Do NOT modify this code. The content of this method is always 
    * regenerated by the Form Editor. 
    */ 
    @SuppressWarnings("unchecked") 
    // <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents 
    private void initComponents() { 

     jPanel2 = new javax.swing.JPanel(); 
     buttonDraw = new javax.swing.JButton(); 
     fieldX = new javax.swing.JTextField(); 
     fieldY = new javax.swing.JTextField(); 
     fieldIter = new javax.swing.JTextField(); 
     jLabel1 = new javax.swing.JLabel(); 
     jLabel2 = new javax.swing.JLabel(); 
     jLabel3 = new javax.swing.JLabel(); 
     panelCanvas = new javax.swing.JPanel(){ 

      @Override 
      protected void paintComponent(Graphics g) { 

       super.paintComponent(g); 

       ArrayList<Point> dragonPoints = DragonData.getDragonPoints(); 
       int newPointsCount = dragonPoints.size(); 

       System.out.println("REPAINT BEFORE"); 

       for(int i = 0 ; i < newPointsCount; i++){ 
        int pointX = (int) dragonPoints.get(i).getX() + 100; 
        int pointY = (int) dragonPoints.get(i).getY(); 

        g.drawRect(pointX, pointY, 1, 1); 
       } 
      } 
     }; 
     panelCanvas = new javax.swing.JPanel(); 
     jLabel4 = new javax.swing.JLabel(); 

     setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 
     setMinimumSize(new java.awt.Dimension(800, 600)); 
     setResizable(false); 

     jPanel2.setBackground(new java.awt.Color(255, 255, 255)); 

     buttonDraw.setText("Draw Dragon"); 
     buttonDraw.addActionListener(new java.awt.event.ActionListener() { 
      public void actionPerformed(java.awt.event.ActionEvent evt) { 
       buttonDrawActionPerformed(evt); 
      } 
     }); 

     jLabel1.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N 
     jLabel1.setText("X:"); 

     jLabel2.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N 
     jLabel2.setText("Y:"); 

     jLabel3.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N 
     jLabel3.setText("Loops (>=1000)"); 

     javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2); 
     jPanel2.setLayout(jPanel2Layout); 
     jPanel2Layout.setHorizontalGroup(
      jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel2Layout.createSequentialGroup() 
       .addContainerGap() 
       .addComponent(jLabel1) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(fieldX, javax.swing.GroupLayout.PREFERRED_SIZE, 141, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(jLabel2) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(fieldY, javax.swing.GroupLayout.PREFERRED_SIZE, 141, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(jLabel3) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(fieldIter, javax.swing.GroupLayout.PREFERRED_SIZE, 141, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 60, Short.MAX_VALUE) 
       .addComponent(buttonDraw, javax.swing.GroupLayout.PREFERRED_SIZE, 149, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addContainerGap()) 
     ); 
     jPanel2Layout.setVerticalGroup(
      jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel2Layout.createSequentialGroup() 
       .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
       .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING) 
        .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
         .addComponent(fieldX, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) 
         .addComponent(fieldY, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) 
         .addComponent(fieldIter, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) 
         .addComponent(jLabel1) 
         .addComponent(jLabel2) 
         .addComponent(jLabel3)) 
        .addComponent(buttonDraw)) 
       .addGap(49, 49, 49)) 
     ); 

     panelCanvas.setBackground(new java.awt.Color(255, 255, 255)); 
     panelCanvas.setMinimumSize(new java.awt.Dimension(800, 600)); 
     panelCanvas.setPreferredSize(new java.awt.Dimension(800, 600)); 
     panelCanvas.setRequestFocusEnabled(false); 

     jLabel4.setText("Author Label"); 

     javax.swing.GroupLayout panelCanvasLayout = new javax.swing.GroupLayout(panelCanvas); 
     panelCanvas.setLayout(panelCanvasLayout); 
     panelCanvasLayout.setHorizontalGroup(
      panelCanvasLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, panelCanvasLayout.createSequentialGroup() 
       .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
       .addComponent(jLabel4) 
       .addContainerGap()) 
     ); 
     panelCanvasLayout.setVerticalGroup(
      panelCanvasLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, panelCanvasLayout.createSequentialGroup() 
       .addContainerGap(575, Short.MAX_VALUE) 
       .addComponent(jLabel4) 
       .addContainerGap()) 
     ); 

     javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 
     getContentPane().setLayout(layout); 
     layout.setHorizontalGroup(
      layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
      .addComponent(panelCanvas, javax.swing.GroupLayout.DEFAULT_SIZE, 817, Short.MAX_VALUE) 
     ); 
     layout.setVerticalGroup(
      layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGroup(layout.createSequentialGroup() 
       .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, 46, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(panelCanvas, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)) 
     ); 

     pack(); 
    }// </editor-fold>//GEN-END:initComponents 

    private void buttonDrawActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_buttonDrawActionPerformed 

     double x = Double.valueOf(this.fieldX.getText()); 
     double y = Double.valueOf(this.fieldY.getText()); 
     int iter = Integer.valueOf(this.fieldIter.getText()); 

     int middleX = this.panelCanvas.getSize().width/2; 
     int middleY = this.panelCanvas.getSize().height/2; 

     DragonData.generatePoints(x, y, iter, middleX, middleY); 

     this.panelCanvas.repaint(); 
    }//GEN-LAST:event_buttonDrawActionPerformed 

    /** 
    * @param args the command line arguments 
    */ 
    public static void main(String args[]) { 
     GUI gui = new GUI(); 
     gui.setLocationRelativeTo(null); 
     gui.setVisible(true); 
    } 
    // Variables declaration - do not modify//GEN-BEGIN:variables 
    private javax.swing.JButton buttonDraw; 
    private javax.swing.JTextField fieldIter; 
    private javax.swing.JTextField fieldX; 
    private javax.swing.JTextField fieldY; 
    private javax.swing.JLabel jLabel1; 
    private javax.swing.JLabel jLabel2; 
    private javax.swing.JLabel jLabel3; 
    private javax.swing.JLabel jLabel4; 
    private javax.swing.JPanel jPanel2; 
    private javax.swing.JPanel panelCanvas; 
    // End of variables declaration//GEN-END:variables 

}

来源

2013-11-27 Michal Angry Programmer

将您的代码发布为文本而不是将来链接到rar文件 – alex2410

确实 - 请不要链接。所有相关的代码应该在这里发布。链接通常被防火墙阻止（正如我所遇到的），并且通常会变得陈旧，因此对于将来访问此网站的用户有类似问题绝对没有帮助。 –

如果你不上传代码，我会自己做。再次，下次如果你自己努力做到这一点，会更好。 –

在方法initComponents()您GUI类：method panelCanvas = new javax.swing.JPanel() {...}并在下一行你重新创建与普通JPanel对象。

所以删除下一行panelCanvas = new javax.swing.JPanel();，一切都会工作。

来源

2013-11-27 22:23:43 alex2410

它工作！非常感谢你！ Netbeans中的内置构建器生成了这个愚蠢的错误:) –

@MichalAngryProgrammer：另一个不使用代码生成器实用程序的原因，至少直到你理解了你正在使用的GUI库。 1+的答案。 –

@MichalAngryProgrammer：再次，请张贴您的代码，以便我可以删除我的倒票。 –

Java - 重绘方法repaint（）不调用paintComponent（）方法

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