focuslistenerbeandemo.java~19~

来自「jbuilder2006一书的所有源代码」· JAVA~19~ 代码 · 共 24 行

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,重新选择编辑框
      tempTextField.grabFocus();
      tempTextField.setSelectionStart(0);
    }
  }
}