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一共有3个类

MainActivity.java 主程序

AlarmReceiver.java 广播接收器

MusicService.java service播放音乐

MainActivity.java

package com.yqy.yqy_alarm;

import java.util.Calendar;

import android.app.Activity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.app.TimePickerDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.text.style.ImageSpan;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.TimePicker;

public class MainActivity extends Activity {

	private TextView tv = null;
    private Button setTime,cancelTime;
    private Calendar c = null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        String alarm = getIntent().getStringExtra("alarm");
        if(alarm != null&&alarm.equals("alarm")){
            stopService(new Intent("com.yqy.yqy_alarm.MUSIC"));
        }

        tv = (TextView)findViewById(R.id.tv);
        setTime = (Button)findViewById(R.id.setAlarm);
        cancelTime = (Button)findViewById(R.id.cancelAlarm);
        //得到日历实例，主要是为了下面的获取时间
        c = Calendar.getInstance();
        setTime.setOnClickListener(new Button.OnClickListener()
        {  

            @Override
            public void onClick(View arg0) {
                c.setTimeInMillis(System.currentTimeMillis());
                int hour = c.get(Calendar.HOUR_OF_DAY);
                int minute = c.get(Calendar.MINUTE);
                new TimePickerDialog(MainActivity.this, minute, new TimePickerDialog.OnTimeSetListener() {
                    @Override
                    public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
                        //是设置日历的时间，主要是让日历的年月日和当前同步
                        c.setTimeInMillis(System.currentTimeMillis());
                        //设置小时分钟，秒和毫秒都设置为0
                        c.set(Calendar.HOUR_OF_DAY, hourOfDay);
                        c.set(Calendar.MINUTE, minute);
                        c.set(Calendar.SECOND, 0);
                        c.set(Calendar.MILLISECOND, 0);  

                        int requestCode = 0;//闹钟的唯一标示
                        Intent intent = new Intent(MainActivity.this, AlarmReceiver.class);
                        intent.putExtra("requestCode", requestCode);
                        PendingIntent pi = PendingIntent.getBroadcast(MainActivity.this, requestCode, intent, 0);
                        //得到AlarmManager实例
                        AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
                        //根据当前时间预设一个警报
                        am.set(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(), pi);
                        /**
                         * 第一个参数是警报类型；第二个参数是第一次执行的延迟时间，可以延迟，也可以马上执行；第三个参数是重复周期为一天
                         * 这句话的意思是设置闹铃重复周期，也就是执行警报的间隔时间
                         */
//                      am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis()+(60*1000),
//                              (24*60*60*1000), pi);
//                        am.setRepeating(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(),
//                                1000*60*5, pi);  

                        String msg = hourOfDay+":"+minute;
                        tv.setText("当前设置的闹钟时间："+msg);
                    }
                }, hour, minute, true).show();
                //上面的TimePickerDialog中的5个参数参考：http://blog.csdn.net/yang_hui1986527/article/details/6839342
            }  

        });  

        cancelTime.setOnClickListener(new Button.OnClickListener()
        {  

            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, AlarmReceiver.class);
                PendingIntent pi = PendingIntent.getBroadcast(MainActivity.this, 0,
                        intent, 0);
                AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
                //取消警报
                am.cancel(pi);
                tv.setText("闹钟取消");
                //取消闹钟的同时取消音乐
                stopService(new Intent("com.yqy.yqy_alarm.MUSIC"));
            }  

        });
    }
}

AlarmReceiver

package com.yqy.yqy_alarm;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class AlarmReceiver extends BroadcastReceiver {

	Intent intent;
	int requestCode = -1;

	@Override
	public void onReceive(Context context, Intent arg1) {

		requestCode = arg1.getIntExtra("requestCode", 0);

		NotificationManager nm = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);
		Notification n = new Notification(R.drawable.ic_launcher, "Hello,there!", System.currentTimeMillis());
		n.flags = Notification.FLAG_AUTO_CANCEL;
		intent = new Intent(context, MainActivity.class);
		intent.putExtra("alarm", "alarm");
		intent.setComponent(new ComponentName("com.yqy.yqy_alarm", "com.yqy.yqy_alarm.MainActivity"));
		intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_NEW_TASK| Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);//关键的一步，设置启动模式
		PendingIntent contentIntent = PendingIntent.getActivity(context, 0,  intent, PendingIntent.FLAG_CANCEL_CURRENT);  

		n.setLatestEventInfo(
		        context,
		        "Hello,there!",
		        "Hello,there,I'm john.",
		        contentIntent);
		nm.notify(R.string.app_name, n);

        Toast.makeText(context, "闹钟时间到", Toast.LENGTH_SHORT).show();
        intent = new Intent("com.yqy.yqy_alarm.MUSIC");
        //启动Service播放音乐
        context.stopService(new Intent("com.yqy.yqy_alarm.MUSIC"));
        context.startService(intent);  

	}

}

MusicService

package com.yqy.yqy_alarm;

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.IBinder;

public class MusicService extends Service {
    private MediaPlayer player;
    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return null;
    }  

    public void onStart(Intent intent, int startId)
    {
        super.onStart(intent, startId);
        player = MediaPlayer.create(this, R.raw.beep);
        player.setLooping(true);
        player.start();
    }
    public void onDestroy()
    {
        super.onDestroy();
        if(player != null){
            player.stop();
        }
    }  

}