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我在Netbeans中製作了一個圖形界面，您可以在文本框「punten」中放入一系列數字（例如：7 8 5 4 10 13），並且當您按下「ververs」按鈕時，所有數字的圖形線條圖應該出現（在我的面板中）。我創建了一個類「Gui」，它擴展了JFrame中的Textfield，按鈕和一個面板。我還創建了一個擴展JPanel的「Grafiek」類，並與我的「Gui」中的面板相關聯。重繪不起作用，我的私人領域的價值不會改變？
我遇到的問題是：repaint（）;命令不會去paintComponent（Graphics g） - 方法，我的私有變量不會改變（punt和punti的長度保持爲0）。
有人可以幫助我，我一直在這個項目上工作了好幾天。
我的GUI類：
import java.awt.Graphics;
public class Gui extends javax.swing.JFrame {
public Gui() {
initComponents();
panel = new javax.swing.JPanel();
}
/**
* 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">
private void initComponents() {
punten = new javax.swing.JTextField();
fout = new javax.swing.JLabel();
javax.swing.JButton ververs = new javax.swing.JButton();
panel = new Grafiek();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
fout.setText("j");
ververs.setText("Ververs");
ververs.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
verversActionPerformed(evt);
}
});
panel.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0), 2));
javax.swing.GroupLayout panelLayout = new javax.swing.GroupLayout(panel);
panel.setLayout(panelLayout);
panelLayout.setHorizontalGroup(
panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 0, Short.MAX_VALUE)
);
panelLayout.setVerticalGroup(
panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 195, Short.MAX_VALUE)
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(panel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(punten, javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addComponent(ververs)
.addGap(6, 6, 6)
.addComponent(fout)
.addGap(0, 302, Short.MAX_VALUE)))
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(punten, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(panel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(fout)
.addComponent(ververs))
.addContainerGap())
);
pack();
}// </editor-fold>
private void verversActionPerformed(java.awt.event.ActionEvent evt) {
Grafiek graf = new Grafiek();
graf.verwerkData(punten.getText());
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Gui.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Gui.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Gui.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Gui.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Gui().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JLabel fout;
private javax.swing.JPanel panel;
private javax.swing.JTextField punten;
// End of variables declaration
}
而我的 「Grafiek」 級：
import java.awt.Graphics;
public class Grafiek extends javax.swing.JPanel {
private String[] punt;
private int[] punti;
private int afstandX, afstandY, puntX1=0, puntY1=0, puntX2=0, puntY2=0;
private int max=1;
/**
* Creates new form Grafiek
*/
public Grafiek() {
initComponents();
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
try{
for(int i=0; i<punti.length; i++) {
if(max <= punti[i]) {
max = punti[i];
}
}
afstandX = getWidth()/punt.length;
afstandY = getHeight()/max;
for(int i=0; i<punti.length; i++) {
puntX1 = puntX2;
if(i == 0) {
puntY1 = getHeight();
}
else puntY1 = puntY2;
puntX2 += afstandX;
puntY2 = getHeight() - punti[i]*afstandY;
g.drawLine(puntX1, puntY1, puntX2, puntY2);
}
puntX2 = 0;
puntY2 = 0;
}catch(java.lang.NullPointerException npe) {
super.paintComponent(g);
}
}
public void verwerkData(String s) {
punt = s.split(" ");
punti = new int[punt.length];
for(int i=0; i<punt.length; i++) {
punti[i] = Integer.parseInt(punt[i]);
}
repaint();
}
/**
* 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">
private void initComponents() {
setBackground(new java.awt.Color(255, 255, 255));
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
this.setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 400, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 300, Short.MAX_VALUE)
);
}// </editor-fold>
}