強制JTextField在其出現時選擇其所有內容

Question

我有一個JLabel，當你點擊它時，它被替換爲JTextField，我需要JTextField來自動選擇它的所有文本。

感謝allot的幫助。

Answer 1

解決方法一：通過焦點事件做吧。不是最好的解決方案。

public static void main(final String[] args) { 
    // simple window preparation 
    final JFrame f = new JFrame(); 
    f.setBounds(200, 200, 400, 400); 
    f.setVisible(true); 

    { // this sleep part shall simulate a user doing some stuff 
     try { 
      Thread.sleep(2345); 
     } catch (final InterruptedException ignore) {} 
    } 

    { // here's the interesting part for you, this is what you put inside your button listener or whatever 
     final JTextField t = new JTextField("Hello World!"); 
     t.addFocusListener(new FocusListener() { 
      @Override public void focusLost(final FocusEvent pE) {} 
      @Override public void focusGained(final FocusEvent pE) { 
       t.selectAll(); 
      } 
     }); 
     f.add(t); 
     f.validate(); 

     t.requestFocus(); 
    } 
} 

Answer 2

JTextField類包含其API中的方法。

這可以幫助：

http://forums.codeguru.com/showthread.php?308517-How-do-you-highlight-the-text-in-a-JTextfield

Answer 3

JTextField.selectAll()是你所需要的。

import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*; 

public class SelectAll 
{ 
    private int count = 0; 

    private void displayGUI() 
    { 
     JFrame frame = new JFrame("Select All"); 
     frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); 

     final JPanel contentPane = new JPanel(); 
     JButton addButton = new JButton("Add"); 
     addButton.addActionListener(new ActionListener() 
     { 
      @Override 
      public void actionPerformed(ActionEvent ae) 
      { 
       JTextField tfield = new JTextField(10); 
       tfield.setText("" + (++count));    
       contentPane.add(tfield); 
       tfield.requestFocusInWindow(); 
       tfield.selectAll(); 

       contentPane.revalidate(); 
       contentPane.repaint(); 
      } 
     }); 

     contentPane.add(addButton); 

     frame.setContentPane(contentPane); 
     frame.pack(); 
     frame.setLocationByPlatform(true); 
     frame.setVisible(true); 
    } 
    public static void main(String... args) 
    { 
     EventQueue.invokeLater(new Runnable() 
     { 
      @Override 
      public void run() 
      { 
       new SelectAll().displayGUI(); 
      } 
     }); 
    } 
}