图形界面中如何控制在文本框里面只能输入数字字符

图形界面中如何控制在文本框里面只能输入数字字符

import java.awt.FlowLayout;

import java.awt.Frame;

import java.awt.Label;

import java.awt.TextField;

import java.awt.event.KeyAdapter;

import java.awt.event.KeyEvent;

import java.awt.event.WindowAdapter;

import java.awt.event.WindowEvent;

 

/*

 * 你输入的如果是非数字字符，就取消你键盘录入的效果。

 */

public class FrameDemo {

         publicstatic void main(String[] args) {

                   //创建窗体对象并设置属性

                   Framef = new Frame("不能输入非数字字符");

                   f.setBounds(400,200, 400, 300);

                   f.setLayout(newFlowLayout());

 

                   //创建Label标签对象

                   Labellabel = new Label("请输入你的QQ号码，不能是非数字，不信你试试");

                   TextFieldtf = new TextField(40);

 

                   //添加到窗体上

                   f.add(label);

                   f.add(tf);

 

                   //设置窗体关闭

                   f.addWindowListener(newWindowAdapter() {

                            @Override

                            publicvoid windowClosing(WindowEvent e) {

                                     System.exit(0);

                            }

                   });

 

                   //给文本框添加事件

                   tf.addKeyListener(newKeyAdapter() {

                            @Override

                            publicvoid keyPressed(KeyEvente) {

                                     //如果你取得的字符不是数字字符就取消事件

                                     //思路：先获取字符，判断字符，取消事件

                                     //char getKeyChar() 

                                     charch = e.getKeyChar();

//                                  System.out.println(ch);

                                     if(!(ch>='0'&& ch<='9')){

                                               e.consume();

                                     }

                            }

                   });

 

                   //设置窗体可见

                   f.setVisible(true);

         }

}