我有兩個類,第一個是NewJFrame.java。它的代碼是 -如何從其他類訪問jFrame的組件?
package javaapplication10;
import java.awt.Label;
public class NewJFrame extends javax.swing.JFrame {
public NewJFrame() {
initComponents();
}
private void initComponents() {
jButton1 = new javax.swing.JButton();
f = new javax.swing.JTextField();
l = new java.awt.Label();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jButton1.setText("jButton1");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
l.setText("label1");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(139, 139, 139)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(f, javax.swing.GroupLayout.PREFERRED_SIZE, 76, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addComponent(l, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButton1, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
.addContainerGap(185, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(f, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(jButton1)
.addGap(22, 22, 22)
.addComponent(l, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(186, Short.MAX_VALUE))
);
pack();
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
System.out.println("Calling");
NewClass1 n = new NewClass1();
n.st();
}
public static void main(String args[]) {
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(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new NewJFrame().setVisible(true);
}
});
}
protected javax.swing.JTextField f;
protected javax.swing.JButton jButton1;
protected java.awt.Label l;
}
我正在使用netbeans。碼的主要 線 -
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
System.out.println("Calling");
NewClass1 n = new NewClass1();
n.st();
}
和變量聲明
protected javax.swing.JTextField f;
protected javax.swing.JButton jButton1;
protected java.awt.Label l;
我的第二類是NewClass.java及其代碼是 - 包javaapplication10;
import java.awt.Label;
public class NewClass1 extends NewJFrame{
public void st()
{
l.setText(f.getText());
}
}
我想要做的就是按一下按鈕(的jButton1),並寫在文本框(六)必須在標籤(L)設置的文本。 當我點擊按鈕「調用」打印在控制檯上但標籤上的文本沒有改變。問題是什麼?請幫忙。
對不起'tf'是錯的。它的'f'只。我編輯了這個問題。 –
1)參見[使用多個JFrames,好/壞實踐?](http://stackoverflow.com/a/9554657/418556)2)'import java.awt.Label; public class NewJFrame extends javax.swing.JFrame {' 除非必要,否則不要混合使用Swing('JFrame')和AWT('Label')組件。在這種情況下,使用'JLabel'而不是'Label'。 3)除非必要,否則不要擴展框架(或對話框)。在這種情況下,只需使用組件的一個實例。 –