我有一个 jTextfield。我想在加载表单时将重点放在此上。我怎样才能做到这一点？我正在使用 Netbeans。我使用requestFocus()但它不起作用。
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4 回答
3
此链接可能对您有帮助：如何使用焦点子系统
我建议您使用 requestFocusInWindow() 而不是 requestFocus() 来实现所需的功能。
原因：（来自同一链接）
这些方法现在已弃用。不鼓励使用另一种方法 requestFocus，因为它试图将焦点赋予组件的窗口，这并不总是可行的。从 JDK 1.4 开始，您应该改用 requestFocusInWindow 方法，它不会尝试使组件的窗口聚焦。该方法返回一个布尔值，指示该方法是否成功。
这将是一个粗略的示例，但我认为您可以使用它来开始：
import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
public class TestFrame extends JFrame {
JButton button1;
JButton button2;
JTextField textField;
public TestFrame() {
initComponents();
}
private void initComponents(){
button1 = new JButton("Button 1");
button2 = new JButton("Button 2");
textField = new JTextField();
button1.setPreferredSize(new Dimension(100,20));
button2.setPreferredSize(new Dimension(100,20));
textField.setPreferredSize(new Dimension(300,20));
this.setSize(new Dimension(600, 300));
this.setLayout(new BorderLayout());
getContentPane().add(button1, BorderLayout.WEST);
getContentPane().add(button2, BorderLayout.CENTER);
getContentPane().add(textField, BorderLayout.EAST);
this.pack();
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//This will set focus on the text field
textField.requestFocusInWindow();
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TestFrame();
}
});
}
}
最新编辑：对于 NETBEANS
使用的代码：
package focusexample;
public class FocusExample extends javax.swing.JFrame {
public FocusExample() {
initComponents();
jTextField1.requestFocusInWindow();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jTextField1 = new javax.swing.JTextField();
jTextField2 = new javax.swing.JTextField();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jButton1.setText("jButton1");
jButton2.setText("jButton2");
jTextField1.setText("jTextField1");
jTextField2.setText("jTextField2");
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(87, 87, 87)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jButton1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jTextField1))
.addGap(69, 69, 69)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jButton2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jTextField2))
.addContainerGap(98, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(95, 95, 95)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jButton2))
.addGap(58, 58, 58)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(104, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
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(FocusExample.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(FocusExample.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(FocusExample.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(FocusExample.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new FocusExample().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField2;
// End of variables declaration
}
于 2012-06-30T03:46:58.057 回答
0
我使用了 textfield.requestFocusInWindow(); 上面给出的行，在一个包含许多表单元素（其中几个是文本字段）的 GUI 中。它工作得很好。只需将“textfield”替换为您为相关元素指定的任何名称。就我而言，它是repId。所以我使用 repID.requestFocusInWindow(); 并将该行放在我的 ENTER 按钮处理程序的底部。现在，当用户在表单域中输入数据并按下 ENTER 时，焦点将返回到第一个文本域：“repID”。感谢你的回答。
于 2014-10-31T21:45:47.753 回答
0
Also of note, make sure you place the requestFocusInWindow() method after the pack() method. When I was placing the requestFocusInWindow() method before the pack() method, it didn't work. I placed the requestFocusInWindow() method after the pack() method and it worked. Little things like that just make life so much easier for us n00bs.
于 2018-02-14T22:46:17.410 回答
0
我希望这个例子能帮助你：
JTextField inputText = new JTextField(20);
frame.addWindowFocusListener(new WindowAdapter() {
public void windowGainedFocus(WindowEvent e) {
inputText.requestFocusInWindow();
}
});
于 2020-03-05T13:27:42.517 回答