代码如下:
package test;
import java.awt.*;
import java.awt.event.*;
public class NumberFormatTest extends Frame
//implements ActionListener
{
private TextField tf;//声明三个对象
private Button btn;
private List list;
public static void main(String[] args) {
NumberFormatTest test=new NumberFormatTest();
test.setSize(300,200);
test.setVisible(true);
}
public void NumberFormatTest() {
Panel panel=new Panel();
tf=new TextField();
btn=new Button("确定");
//btn.addActionListener(this);
list=new List();
panel.add(new Label("请输入数字"));
panel.add(tf);
add(panel,BorderLayout.NORTH);
add(btn,BorderLayout.SOUTH);
add(list,BorderLayout.CENTER);
}
public void actionPerformed(ActionEvent e) {
int num;
try {
num=Integer.parseInt(tf.getText());
list.removeAll();
list.add(Integer.toString(num));
}catch(NumberFormatException exc)
{
tf.setText("");
}
}
}