focuslistenerbeandemo.java~16~

jbuilder2006一书的所有源代码

package event;

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

public class FocusListenerBeanDemo implements FocusListener {
  public void focusGained(FocusEvent e) {
  }
  public void focusLost(FocusEvent e) {
    //取得编辑框对象
    JTextField tempTextField = (JTextField) e.getSource();
    String tempStr = tempTextField.getText();
    //尝试将编辑框的字符转换为数值
    try {
      Double d1 = Double.valueOf(tempStr);
    }
    catch (Exception el) {
      //如果不成功,将编辑框的字符串还原
      ( (JTextField) e.getSource()).setText(tempStr);
    }
  }
}