怎么样在java中弹出一个messagebox

在java中实现一个消息框, 常见的有两种方式

第一种方法: JOptionPane 类. 创建1个弹窗.

例一:简单的消息提示框

JOptionPane.showMessageDialog(null, "消息提示");

2.例二:带警告图片的消息提示框

JOptionPane.showMessageDialog(null, "提示消息", "标题",JOptionPane.WARNING_MESSAGE);

第二种方法 弹窗JDialog 设置setModal(true); 也可以实现. 类似于写JFrame

两者区别在于:

JOptionPane 代码简短, 适应一些普通需求, 比如弹出消息提示, 弹出警告信息, 提示用户输入, 提示用户选择, 等简单的场景

JDialog 代码略长, 组件需要自行定义.  满足一些复杂的需求. 比如多个输入框 ,多个按钮等

这样：

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.awt.Graphics;

public class MainClass extends JFrame {

public JComboBox box;

int flag = 0;

jpNewPanel jpNewPanel;

public static void main(String[] args) {

MainClass frame = new MainClass();

frame.setBounds(650,300,550,550);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setTitle("信号灯");

frame.setVisible(true);

}

public MainClass() {

box = new JComboBox();

box.addItem("请选择");

box.addItem("红灯");

box.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

flag = box.getSelectedIndex();

jpNewPanel.repaint();

}

});

box.addItem("黄灯");

box.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

flag = box.getSelectedIndex();

jpNewPanel.repaint();

}

});

box.addItem("绿灯");

box.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

flag = box.getSelectedIndex();

jpNewPanel.repaint();

}

});

add(box, BorderLayout.NORTH);

jpNewPanel = new jpNewPanel();

add(jpNewPanel, BorderLayout.CENTER);

}

class jpNewPanel extends JPanel {

protected void paintComponent(Graphics g) {

super.paintComponent(g);

g.drawOval(150, 0, 120, 120);

if (flag == 1) {

g.setColor(Color.RED);

g.fillOval(150, 0, 120, 120);

} else if (flag == 2) {

g.setColor(Color.YELLOW);

g.fillOval(150, 0, 120, 120);

} else if (flag == 3) {

g.setColor(Color.GREEN);

g.fillOval(150, 0, 120, 120);

}

}

}

}

扩展资料：

注意事项

每个Road对象都有一个name成员变量来代表方向，有一个vehicles成员变量来代表方向上的车辆集合。

在Road对象的构造方法中启动一个线程每隔一个随机的时间向vehicles集合中增加一辆车(用一个“路线名_id”形式的字符串进行表示)。

在Road对象的构造方法中启动一个定时器，每隔一秒检查该方向上的灯是否为绿，是则打印车辆集合和将集合中的第一辆车移除掉。

一个关于定时提醒的弹窗例子，还不是很成熟，仅供参考

//主窗口界面设计

public class TestButtons {

JFrame frame = new JFrame("提醒");

JButton jButton = new JButton("开始运行"); //按钮

JCheckBox checkBox = new JCheckBox("早上提醒"); //复选按钮

JCheckBox checkBox1 = new JCheckBox("晚上提醒"); //复选按钮

JLabel label = new JLabel("Ready to run."); //静态文本

//构造函数我爱编程网

public TestButtons() {

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.getContentPane().setLayout(new java.awt.FlowLayout());

//为按钮添加动作监听器

jButton.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent ae) {

//按钮事件处理程序

label.setText("Thread keep running.");

int i=Timetorun()*1000;

try {

Thread.sleep(i);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

JFrame parent = new JFrame();

JOptionPane.showMessageDialog(parent, "该干啥了。");

}

});

//早上提醒 复选框处理程序

checkBox.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {

JCheckBox cb = (JCheckBox) e.getSource();

label.setText("Selected Check Box is " + cb.isSelected());

}

});

//晚上提醒 复选框处理程序

checkBox1.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {

JCheckBox cb = (JCheckBox) e.getSource();

label.setText("Selected Check Box is " + cb.isSelected());

}

});

//添加组件到容器

frame.getContentPane().add(jButton);

frame.getContentPane().add(checkBox);

frame.getContentPane().add(checkBox1);

frame.getContentPane().add(label);

frame.setSize(200, 250);

}

public void show() {

frame.show();

}

//主处理函数

public static void main(String[] args) {

TestButtons tb = new TestButtons();

tb.show();

}

//时间处理函数

public static int Timetorun(){

//获取系统当前时间

Calendar cal=Calendar.getInstance();

int nowhour=cal.get(Calendar.HOUR_OF_DAY);

int nowminite=cal.get(Calendar.MINUTE);

int nowweek=cal.get(Calendar.DAY_OF_WEEK);

System.out.println(nowhour+"");

System.out.println(nowminite+"");

System.out.println(nowweek+"");

int dehour=0;

int deminite=0;

//获取延迟时间

if(nowweek==2 || nowweek==3 || nowweek==5){

if(nowminite<=30 && nowhour<=20){

deminite=30-nowminite;

dehour=20-nowhour;

}

else if(nowminite>30 && nowhour<=20){

deminite=90-nowminite;

dehour=19-nowhour;

}

else if (nowminite<=30 && nowhour>20) {

deminite=30-nowminite;

dehour=44-nowhour;

}

else {

deminite=90-nowminite;

dehour=43-nowhour;

}}

else if(nowweek==4 || nowweek==6 || nowweek==7 || nowweek==1){

if(nowminite<=30 && nowhour<=17){

deminite=30-nowminite;

dehour=17-nowhour;

}

else if(nowminite>30 && nowhour<=17){

deminite=90-nowminite;

dehour=16-nowhour;

}

else if (nowminite<=30 && nowhour>17) {

deminite=30-nowminite;

dehour=41-nowhour;

}

else {

deminite=90-nowminite;

dehour=40-nowhour;

}

}

//延迟时间为K分钟

int k= dehour*60 + deminite;

return k;

}

}