java 使用swing制作一个小闹钟，包含以下功能：

import java.awt.BorderLayout

import java.awt.FlowLayout

import java.awt.Font

import java.awt.Frame

import java.awt.GridLayout

import java.awt.event.ActionEvent

import java.awt.event.ActionListener

import java.awt.event.KeyEvent

import java.awt.event.KeyListener

import java.io.IOException

import java.text.DateFormat

import java.text.SimpleDateFormat

import java.util.Calendar

import java.util.Timer

import java.util.TimerTask

import javax.sound.sampled.AudioInputStream

import javax.sound.sampled.AudioSystem

import javax.sound.sampled.Clip

import javax.sound.sampled.LineEvent

import javax.sound.sampled.LineListener

import javax.sound.sampled.LineUnavailableException

import javax.sound.sampled.UnsupportedAudioFileException

import javax.swing.JButton

import javax.swing.JDialog

import javax.swing.JFrame

import javax.swing.JLabel

import javax.swing.JPanel

import javax.swing.JTextField

/**

* 闹钟主界面

*/

public class AlarmClock extends JFrame implements ActionListener {

private static final int LOOP_COUNT = 5// 重复播放的次数

private JLabel labelClock, labelAlarm, labelNextAlarm

private JButton btnSet, btnClose

private SetDialog setDialog

private JPanel topPanel, alarmPanel

private Timer timer

private Clip clip

private Calendar alarmCal

private boolean timeReached = true

private DateFormat df = new SimpleDateFormat("HH : mm")

public AlarmClock() {

super("闹钟")

}

public void launch() {

setSize(400, 300)

setVisible(true)

setDefaultCloseOperation(EXIT_ON_CLOSE)

getContentPane().setLayout(new BorderLayout())// 利用边界布局将界面分割成上中下三部分

labelAlarm = new JLabel("闹钟定时已到！")

btnClose = new JButton("确定")

labelNextAlarm = new JLabel()// 指示下一次闹钟时间

alarmPanel = new JPanel(new FlowLayout(FlowLayout.CENTER))// 顶部提示栏提示闹钟时间已到，和确定按钮

alarmPanel.add(labelAlarm)

alarmPanel.add(btnClose)

topPanel = new JPanel(new GridLayout(2, 1))

topPanel.add(alarmPanel)

topPanel.add(labelNextAlarm)

alarmPanel.setVisible(false)// 初始隐藏顶部提示栏

labelClock = new JLabel()

Font font = new Font(Font.SERIF, Font.PLAIN, 48)// 中间的倒计时文本用大号字体展示

labelClock.setFont(font)

labelClock.setHorizontalAlignment(JLabel.CENTER)// 文本居中

btnSet = new JButton("设置")

getContentPane().add(topPanel, BorderLayout.NORTH)// 界面顶部

getContentPane().add(labelClock, BorderLayout.CENTER)// 界面中部

getContentPane().add(btnSet, BorderLayout.SOUTH)// 界面底部

btnSet.addActionListener(this)// 设置按钮的点击事件

btnClose.addActionListener(this)// 顶部确定按钮的点击事件

setLocationRelativeTo(null)// 界面居中

setDialog = new SetDialog(this)// 初始化设置对话框

try { // 初始化闹钟声音

// 目前发现wav格式的文件是可以支持的，mp3不支持

AudioInputStream ais = AudioSystem.getAudioInputStream(

AlarmClock.class.getResource("/res/alarm.wav"))

clip = AudioSystem.getClip()

clip.open(ais)

ais.close()

int loop = LOOP_COUNT <= 0 ? 1 : LOOP_COUNT

final long totalFrames = ais.getFrameLength() * loop

clip.addLineListener(new LineListener() {

@Override

public void update(LineEvent e) {

// 当闹钟音乐播放结束时，自动隐藏顶部提示栏

if(e.getFramePosition() >= totalFrames) {

stopAlarm()

}

}

})

} catch (UnsupportedAudioFileException e) {

e.printStackTrace()

} catch (IOException e) {

e.printStackTrace()

} catch (LineUnavailableException e) {

e.printStackTrace()

}

initTimer()

}

public static void main(String[] args) {

new AlarmClock().launch()// 启动主界面

}

@Override

public void actionPerformed(ActionEvent e) {

Object source = e.getSource()

if(source == btnSet) { // 点击设置按钮时d出设置界面，以模对话框显示

setDialog.setVisible(true)

} else if(source == btnClose) { // 点击顶部确定按钮时隐藏顶部提示栏

stopAlarm()

}

}

private void initTimer() {

timer = new Timer()// 初始化倒计时任务

// 开始倒计时

timer.scheduleAtFixedRate(new TimerTask() {

@Override

public void run() {

Calendar cal = Calendar.getInstance()

int hour = cal.get(Calendar.HOUR_OF_DAY)

int min = cal.get(Calendar.MINUTE)

int sec = cal.get(Calendar.SECOND)

// 设置倒计时文本

labelClock.setText(String.format("%02d : %02d : %02d", hour, min, sec))

if(null != alarmCal &&!timeReached) {

int alarmHour = alarmCal.get(Calendar.HOUR_OF_DAY)

int alarmMin = alarmCal.get(Calendar.MINUTE)

if(alarmHour == hour &&alarmMin == min) { // 到时间时播放声音

timeReached = true

System.out.println("Time over")

startAlarm()

}

}

}

}, 0, 1000L)// 每隔1秒刷新倒计时文本

}

/**

* 开始计时

* @param hour

* @param minute

*/

public void startTimer(int hour, int minute) {

alarmCal = Calendar.getInstance()

alarmCal.set(Calendar.HOUR_OF_DAY, hour)

alarmCal.set(Calendar.MINUTE, minute)

labelNextAlarm.setText("下次闹钟时间：" + df.format(alarmCal.getTime()))

timeReached = false

}

/**

* 取消倒计时任务

*/

public void cancelTimer() {

labelNextAlarm.setText("")

alarmCal = null

}

private void startAlarm() { // 开始播放提示音

if(null != clip) {

alarmPanel.setVisible(true)// 显示顶部提示栏

clip.setFramePosition(0)// 将音频帧重置为第0帧

clip.loop(LOOP_COUNT)// 开始循环播放

}

labelNextAlarm.setText("")

}

private void stopAlarm() { // 停止播放提示音

if(null != clip &&clip.isRunning()) {

clip.stop()// 结束播放

}

labelNextAlarm.setText("")

alarmPanel.setVisible(false)// 隐藏顶部提示栏

}

/**

* 闹钟设置页面

*/

class SetDialog extends JDialog implements KeyListener, ActionListener {

private JLabel labelHour, labelMin

private JTextField textHour, textMin

private JPanel mainPanel, labelPanel, buttonPanel

private JButton btnOk, btnCancel, btnBack

private Calendar cal = Calendar.getInstance()

public SetDialog(Frame frame) {

super(frame)

setTitle("设置")

setModal(true)// 设置为模窗口，就是说在本d窗未消失时不允许点击主界面。

setSize(300, 150)

// 显示时分

labelHour = new JLabel("时")

labelMin = new JLabel("分")

labelHour.setHorizontalAlignment(JLabel.CENTER)

labelMin.setHorizontalAlignment(JLabel.CENTER)

textHour = new JTextField()

textMin = new JTextField()

// 上面的部分用网格布局将各组件以2x2的格子放进去

labelPanel = new JPanel(new GridLayout(2, 2))

labelPanel.add(labelHour)

labelPanel.add(labelMin)

labelPanel.add(textHour)

labelPanel.add(textMin)

// 时分输入框添加按键监听，只允许输入数字

textHour.addKeyListener(this)

textMin.addKeyListener(this)

// 初始化按钮

btnOk = new JButton("确定")

btnCancel = new JButton("取消")

btnBack = new JButton("返回")

// 下面的按钮依次居中放进去

buttonPanel = new JPanel(new FlowLayout(FlowLayout.CENTER))

buttonPanel.add(btnBack)

buttonPanel.add(btnCancel)

buttonPanel.add(btnOk)

// 初始化主面板，将主面板分割为上下两部分

mainPanel = new JPanel(new BorderLayout())

mainPanel.add(labelPanel, BorderLayout.CENTER)// 上面显示时分的组件

mainPanel.add(buttonPanel, BorderLayout.SOUTH)// 下面排列三个按钮

setContentPane(mainPanel)

// 设置按钮监听

btnBack.addActionListener(this)

btnOk.addActionListener(this)

btnCancel.addActionListener(this)

cal.add(Calendar.HOUR, 1)// 默认设置为当前时间加1小时的整点时间

cal.set(Calendar.MINUTE, 0)

int hour = cal.get(Calendar.HOUR_OF_DAY)

int min = cal.get(Calendar.MINUTE)

textHour.setText(String.format("%02d", hour))

textMin.setText(String.format("%02d", min))

setLocationRelativeTo(frame)

}

@Override

public void keyPressed(KeyEvent arg0) {

}

@Override

public void keyReleased(KeyEvent arg0) {

}

@Override

public void keyTyped(KeyEvent e) {

int keyChar = e.getKeyChar()

if(keyChar >= KeyEvent.VK_0 &&keyChar <= KeyEvent.VK_9){

}else{ // 如果输入的不是数字则屏蔽输入

e.consume()//关键，屏蔽掉非法输入

}

}

@Override

public void actionPerformed(ActionEvent e) {

Object source = e.getSource()

if(source == btnOk) { // 如果点击了确定按钮，则开始计时

int hour = 0, min = 0

try {

hour = Integer.parseInt(textHour.getText())

} catch (NumberFormatException e1) {

}

try {

min = Integer.parseInt(textMin.getText())

} catch (NumberFormatException e1) {

}

startTimer(hour, min)

setVisible(false)

} else if(source == btnCancel) { // 点击取消按钮时取消计时

cancelTimer()

setVisible(false)

} else if(source == btnBack) { // 点击返回按钮时什么也不做，直接关闭设置界面

setVisible(false)

}

}

}

}

Android是开源的，所以参考它自带的闹钟应用（DeskClock）的源代码。这是CM项目（一个非常流行的Android ROM）带的DeskClock应用，点击ZIP按钮就能把源代码打包下载。

https://github.com/CyanogenMod/android_packages_apps_DeskClock

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