textfieldframe.java

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package component;

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

public class TextFieldFrame extends JFrame implements FocusListener {
  JPanel contentPane;
  JTextField jTextField1 = new JTextField();
  JTextField jTextField2 = new JTextField();

  public TextFieldFrame() {
    try {
      setDefaultCloseOperation(EXIT_ON_CLOSE);
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }
  
  public static void main(String[] args) {
    TextFieldFrame frame = new TextFieldFrame();
    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
    Dimension frameSize = frame.getSize();
    //居中对齐
    frame.setLocation((screenSize.width - frameSize.width) / 2,
        (screenSize.height - frameSize.height) / 2);
    frame.setVisible(true);
  }

  private void jbInit() throws Exception  {
    contentPane = (JPanel) this.getContentPane();
    contentPane.setLayout(null);
    this.setSize(new Dimension(400, 300));
    this.setTitle("编辑框示例");
    jTextField1.setText("编辑框示例");
    jTextField1.setBounds(new Rectangle(83, 83, 235, 33));
    jTextField1.addFocusListener(this);
    jTextField2.setText("编辑框示例");
    jTextField2.setBounds(new Rectangle(83, 150, 235, 33));
    jTextField2.addFocusListener(this);
    contentPane.add(jTextField1, null);
    contentPane.add(jTextField2, null);
  }

  public void focusGained(FocusEvent e) {
    //取得激发事件的控件
    JTextField tempTextField = (JTextField)e.getSource();
    //选择编辑框的字符串
    tempTextField.setSelectionStart(0);
    tempTextField.setSelectionEnd(tempTextField.getText().length());
  }
  public void focusLost(FocusEvent e) {
    //取得激发事件的控件
    JTextField tempTextField = (JTextField)e.getSource();
    //取消编辑框的字符串的选择
    tempTextField.setSelectionStart(0);
    tempTextField.setSelectionEnd(0);
  }
}