一、闹铃功能介绍：
1、为每条备忘添加闹铃
2、备忘内容和闹铃信息存在SQL中
3、可删除每天记录和闹铃或者删除所有

4、到点闹铃启动，包括锁屏时和重开机
5、在桌面的创建一个widget类似便签那样的东西显示记录

二、看下效果图：







三、关于SQL部分不再细写，可查看Android应用开发一栏：
添加闹铃和备忘：
1、设置日期：

dateBtn.setOnClickListener(new OnClickListener() {

				@Override
				public void onClick(View v) {
					mCalendar = Calendar.getInstance();
					// TODO Auto-generated method stub
					new DatePickerDialog(EditTime.this,
							new DatePickerDialog.OnDateSetListener() {
								public void onDateSet(DatePicker view,
										int year, int monthOfYear,
										int dayOfMonth) {

									mAlarmCalendar.set(Calendar.YEAR, year);
									mAlarmCalendar.set(Calendar.MONTH,
											monthOfYear);
									mAlarmCalendar.set(Calendar.DAY_OF_MONTH,
											dayOfMonth);
									EditTime.this.year = year;
									EditTime.this.month = monthOfYear;
									EditTime.this.day = dayOfMonth;
									dateBtn.setText(year + "年" + (month + 1)
											+ "月" + day + "日");
									System.out.println(year+"年"+(monthOfYear+1)+"月"+dayOfMonth+"日");
								}
							}, year, month, day).show();
				}
			});


2、设置时间：


timeBtn.setOnClickListener(new OnClickListener() {

				@Override
				public void onClick(View v) {
					mCalendar = Calendar.getInstance();
					new TimePickerDialog(EditTime.this,
							new TimePickerDialog.OnTimeSetListener() {
								public void onTimeSet(TimePicker view,
										int hourOfDay, int minute) {
									mAlarmCalendar.set(Calendar.HOUR_OF_DAY,
											hourOfDay);
									mAlarmCalendar.set(Calendar.MINUTE, minute);
									mAlarmCalendar.set(Calendar.SECOND, 0);
									mAlarmCalendar.set(Calendar.MILLISECOND, 0);
									EditTime.this.hour = hourOfDay;
									EditTime.this.minute = minute;
									timeBtn.setText(hour + "时" + minute + "分");									
									System.out.println(hourOfDay+"时"+minute+"分");
								}
							}, hour, minute, false).show();
				}
			});


3、广播闹铃：


setBtn.setOnClickListener(new OnClickListener() {

				@Override
				public void onClick(View v) {
					// TODO Auto-generated method stub
					//写进数据库
					addData();
					/* 获取闹钟管理的实例 */

					mAlarm = (AlarmManager) getSystemService(Service.ALARM_SERVICE);
					Intent intent = new Intent(EditTime.this,
							AlarmReceiver.class);
					PendingIntent pendingIntent = PendingIntent.getBroadcast(
							EditTime.this, AlarmIndex, intent, 0);// 第二个参数为区别不同闹铃的唯一标识
					/* 设置闹钟 */
					mAlarm.set(AlarmManager.RTC_WAKEUP,
							mAlarmCalendar.getTimeInMillis(), pendingIntent);
					finish();
				}
			});

4、广播接收BroadcastReceiver：

public class AlarmReceiver extends BroadcastReceiver {
	@Override
	public void onReceive(Context context, Intent intent) {
		// TODO Auto-generated method stub		
		Intent i = new Intent(context, Alarm.class);
		i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);//这一句很重要，不然会出错
		context.startActivity(i);
	}
}



记得注册：


<receiver
            android:name=".AlarmReceiver"
            android:process=":remote" />


5、重启之后重写闹铃，BootReceiver：


public class BootReceiver extends BroadcastReceiver{
		
	@Override
	public void onReceive(Context context, Intent intent) {
		// TODO Auto-generated method stub
		String action = intent.getAction();
		if(action.equals(Intent.ACTION_BOOT_COMPLETED)){
			Intent i = new Intent(context, BootAlarm.class);
			i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);//这一句很重要，不然会出错
			context.startActivity(i);
		}
	}
}
同样需要注册：


<receiver android:name="BootReceiver" >
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
            </intent-filter>
        </receiver>


6、开始重写：


dbHelper = new DatabaseHelper(BootAlarm.this, "idea.sql");
		SQLiteDatabase db = dbHelper.getReadableDatabase();
		Cursor cursor = db.query("user", null, null, null, null, null, null);
		btAlarmCalendar = Calendar.getInstance();
		
			while (cursor.moveToNext()) {
				btAlarmCalendar = Calendar.getInstance();
				System.out.println("cursor.moveToNext()-->cursor.getInt(0)-->"
						+ cursor.getInt(0));
				time = cursor.getString(cursor.getColumnIndex("mtime"));
				year = time.substring(0, time.indexOf("年"));
				myear = Integer.valueOf(year).intValue();
				month = time.substring(time.indexOf("年")+1, time.indexOf("月"));
				mmonth = Integer.valueOf(month).intValue()-1;
				day = time.substring(time.indexOf("月")+1, time.indexOf("日"));
				mday = Integer.valueOf(day).intValue();
				hour = time.substring(time.indexOf("日")+1, time.indexOf("时"));
				mhour = Integer.valueOf(hour).intValue();
				minute = time.substring(time.indexOf("时")+1, time.indexOf("分"));
				mminute = Integer.valueOf(minute).intValue();
				System.out.println(myear + "年" + mmonth + "月" + mday + "日"
						+ mhour + "时" + mminute);
				btAlarmCalendar.set(Calendar.YEAR, myear);
				btAlarmCalendar.set(Calendar.MONTH, mmonth);
				btAlarmCalendar.set(Calendar.DAY_OF_MONTH, mday);
				btAlarmCalendar.set(Calendar.HOUR_OF_DAY, mhour);
				btAlarmCalendar.set(Calendar.MINUTE, mminute);
				btAlarmCalendar.set(Calendar.SECOND, 0);
				btAlarmCalendar.set(Calendar.MILLISECOND, 0);
				mAlarm = (AlarmManager) getSystemService(Service.ALARM_SERVICE);
				intent = new Intent(BootAlarm.this, AlarmReceiver.class);
				pendingIntent= PendingIntent.getBroadcast(
						BootAlarm.this, cursor.getInt(0), intent, 0);// 第二个参数为区别不同闹铃的唯一标识
				/* 设置闹钟 */
				mAlarm.set(AlarmManager.RTC_WAKEUP,
						btAlarmCalendar.getTimeInMillis(), pendingIntent);
			}


这里有个很需要注意的：


intent = new Intent(BootAlarm.this, AlarmReceiver.class);
				pendingIntent= PendingIntent.getBroadcast(
						BootAlarm.this, cursor.getInt(0), intent, 0);


若是PendingIntent.getBroadcas，则intent必须为启动的是BroadcastReceiver，不然重写不会成功的。



7、到点闹铃响，这是由AlarmReceiver（继承BroadcastReceiver）启动的：

dbHelper = new DatabaseHelper(Alarm.this, "ideal.sql");
		SQLiteDatabase db = dbHelper.getReadableDatabase();
		Cursor cursor = db.query("user", null, "_id=?",
				new String[] { NoteActivity.Alarming_index + "" }, null, null,
				null);
		if (cursor.moveToFirst()) {
			mtime = cursor.getString(cursor.getColumnIndex("mtime"));
			mtext = cursor.getString(cursor.getColumnIndex("mtext"));
		}
		db.close();
		addData();//写进历史记录表中
		deleteData(NoteActivity.Alarming_index);//删除原来记录
		
		new AlertDialog.Builder(Alarm.this)
				.setIcon(R.drawable.bell)
				.setTitle("It's time to do something.")
				.setMessage(mtext)
				.setPositiveButton("Done",
						new DialogInterface.OnClickListener() {
							public void onClick(DialogInterface dialog,
									int whichButton) {
								deleteData(NoteActivity.Alarming_index);//再次删除确认
								//关闭闹铃声
								Intent intentSV = new Intent(Alarm.this, MyService.class);
								stopService(intentSV);
								Alarm.this.finish();
							}
						}).show();


锁屏时也启动闹铃：


//下面是为了在锁屏时也能启动闹铃
		getWindow().addFlags(
                WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
                                | WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
		getWindow().addFlags(
                WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON
                                | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
8、置于闹铃音乐可以写一个Service，这个可查看Android学习笔记一栏

9、点击listview可查看记录内容，长按可进行记录的删除，这里不再多写。

10、由于是闹铃，所以必须每一秒中进行更新一下倒计时，这个可以查看Android学习笔记一栏。
11、附：让title每秒显示时间：

	public class TimeThread extends Thread {
		@Override
		public void run() {
			do {
				try {
					Thread.sleep(1000);
					Message msg = new Message();
					msg.what = 1;
					mHandler.sendMessage(msg);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			} while (true);
		}
	}

	private Handler mHandler = new Handler() {
		@Override
		public void handleMessage(Message msg) {
			super.handleMessage(msg);
			switch (msg.what) {
			case 1:
				currentTime = new Date();
				// long sysTime = System.currentTimeMillis();
				CharSequence sysTimeStr = DateFormat.format(
						"yyyy年MM月dd日hh:mm:ss", currentTime.getTime());
				EditTime.this.setTitle(sysTimeStr);
				break;

			default:
				break;
			}
		}
	};

------------------（修改版）----------------------


12、是否为记录添加闹铃：


isAlarmBtn.setOnClickListener(new OnClickListener() {

				@Override
				public void onClick(View v) {
					// TODO Auto-generated method stub
					isAlarmNum++;
					if (isAlarmNum % 2 == 0) {
						isAlarmBtn.setBackgroundResource(R.drawable.checknull);
						isAlarm = 0;
					} else {
						isAlarmBtn.setBackgroundResource(R.drawable.check);
						isAlarm = 1;
					}
				}
			});


13、阻止设置时间小于当前时间：


currentTime = new Date();
					if (beginTime.getTime() < currentTime.getTime()) {
						Toast.makeText(EditTime.this, "设置时间不能小于当前时间！",
								Toast.LENGTH_SHORT).show();
					}


14、添加widget：

AppWidget.java

public class AppWidget extends AppWidgetProvider {

	private DatabaseHelper dbHelper;
	String[] desk_text;
	@Override
	public void onUpdate(Context context, AppWidgetManager appWidgetManager,
			int[] appWidgetIds) {
		// TODO Auto-generated method stub
		super.onUpdate(context, appWidgetManager, appWidgetIds);
		//读取数据库中的记录
		dbHelper = new DatabaseHelper(context, "ideal.sql");
		SQLiteDatabase db = dbHelper.getReadableDatabase();
		Cursor cursor = db.query("user", null, null, null, null, null, null);
		int desk_num=0;
		//桌面的便签只显示6条记录
		desk_text = new String[6];
		while(cursor.moveToNext()){
			if(desk_num == 6){
				break;
			}
			String temp_text = cursor.getString(cursor.getColumnIndex("mtext"));
			//控制每条记录显示的长度
			if(temp_text.length()>7){
				temp_text=temp_text.substring(0, 7)+"...";
			}
			desk_text[desk_num]=temp_text;
			System.out.println("desk_text[desk_num]"+desk_text[desk_num]);
			desk_num++;			
		}
		db.close();
		final int Num = appWidgetIds.length;
		for (int i = 0; i < Num; i++) {
			int[] mAppWidgetId = appWidgetIds;
			RemoteViews mRemoteViews = new RemoteViews(context.getPackageName(),
					R.layout.widget);
			mRemoteViews.setTextViewText(R.id.desktop_text, array_to_string(desk_text));

			Intent clickIntent = new Intent(context, NoteActivity.class);
			PendingIntent pdIntent = PendingIntent.getActivity(context, 0,
					clickIntent, 0);
			mRemoteViews.setOnClickPendingIntent(R.id.widget_layout, pdIntent);
			appWidgetManager.updateAppWidget(mAppWidgetId, mRemoteViews);
		}
	}
	//onReceive方法用来接收广播，以便更新桌面的便签
	
	@Override
	public void onReceive(Context context, Intent intent) {
		// TODO Auto-generated method stub
		super.onReceive(context, intent);
		if(intent.getAction().equals("com.ideal.note.widget")){
			dbHelper = new DatabaseHelper(context, "ideal.sql");
		SQLiteDatabase db = dbHelper.getReadableDatabase();
		Cursor cursor = db.query("user", null, null, null, null, null, null);
		int desk_num=0;
		desk_text = new String[6];
		while(cursor.moveToNext()){
			if(desk_num == 6){
				break;
			}
			String temp_text = cursor.getString(cursor.getColumnIndex("mtext"));
			if(temp_text.length()>7){
				temp_text=temp_text.substring(0, 7)+"...";
			}
			desk_text[desk_num]=temp_text;
			System.out.println("desk_text[desk_num]"+desk_text[desk_num]);
			desk_num++;			
		}
		db.close();
		}
		RemoteViews mRemoteViews = new RemoteViews(context.getPackageName(), R.layout.widget);
		mRemoteViews.setTextViewText(R.id.desktop_text, array_to_string(desk_text));
		AppWidgetManager.getInstance(context).updateAppWidget(new ComponentName(context, AppWidget.class), mRemoteViews);		
	}
	
	//数组转化为字符显示
	public String array_to_string(String[] array){
		String temp_str = "";
		for(int i=0;i<array.length;i++){
			if(array[i]==null){
				break;
			}else {
				temp_str = temp_str+"\n* "+array[i];
			}
		}
		return  temp_str;
	}
}


在其他修改了数据库数据的Activity或者其他地方发送一条广播来让AppWidget执行，如在NoteActivity.java中添加：


Intent mWidgetIntent = new Intent();
				mWidgetIntent.setAction("com.ideal.note.widget");
				NoteActivity.this.sendBroadcast(mWidgetIntent);


另，还需在AndroidManifest.xml中添加：


<receiver android:name=".AppWidget"> 
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE"/>
                <action android:name="com.ideal.note.widget"/>
            </intent-filter>
            <meta-data  android:name="android.appwidget.provider"
           	android:resource="@xml/appwidget_info"/> 
        </receiver>

附源码下载地址：http://download.csdn.net/detail/moruna/7969393
有疑问的可加入这个qq群聊一起讨论：431922622（奋斗的Android青年 ）

此demo实现了一个闹铃，用AlarmManager对象设定闹铃，时间到了后，系统会调用设定好的BroadcastReceiver、Service或者Activity。

AlarmManager可以设置以下五种类型（demo中使用的第二种）： 


注意：此demo在原生Android系统上没问题，但在国内大多数定制机上，如果关闭后台，闹铃一般不会触发 ╮(╯_╰)╭

demo下载地址：http://download.csdn.net/detail/youmingyu/9715802

MainAvtivity：

package fk.androiddemo_030;

import android.app.Activity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
    Button setAlarmBut,cancelAlarmBut;
    EditText keyEdit,timeEdit;
    int alarmKey, alarmTime;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        keyEdit=(EditText)findViewById(R.id.keyEdit);
        timeEdit=(EditText)findViewById(R.id.timeEdit);

        setAlarmBut = (Button) findViewById(R.id.setAlarmBut);
        setAlarmBut.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                alarmKey=Integer.parseInt(keyEdit.getText().toString().trim());
                alarmTime=Integer.parseInt(timeEdit.getText().toString().trim());
                alarmTime=alarmTime*1000;//换成毫秒

                Intent intent = new Intent(MainActivity.this, AlarmService.class);
                //Intent intent = new Intent(MainActivity.this, AlarmReceiver.class);
                intent.putExtra("alarmKey",alarmKey);

                //PendingIntent还可以用getActivity()直接启动Activity
                PendingIntent sender = PendingIntent.getService(MainActivity.this, alarmKey, intent, 0);
                //PendingIntent sender = PendingIntent.getBroadcast(MainActivity.this, alarmKey, intent, 0);

                long firstTime = SystemClock.elapsedRealtime(); // 开机之后到现在的运行时间(包括睡眠时间)
                firstTime += alarmTime;

                // 进行闹铃注册
                AlarmManager manager = (AlarmManager) getSystemService(ALARM_SERVICE);
                //manager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, firstTime, 3000, sender);//重复闹钟
                manager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, firstTime, sender);

                Toast.makeText(MainActivity.this, "设置"+alarmKey+"号闹铃", Toast.LENGTH_LONG).show();

                //MainActivity.this.finish();
            }
        });

        cancelAlarmBut = (Button) findViewById(R.id.cancelAlarmBut);
        cancelAlarmBut.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                alarmKey=Integer.parseInt(keyEdit.getText().toString().trim());

                Intent intent = new Intent(MainActivity.this, AlarmService.class);
                //Intent intent = new Intent(MainActivity.this, AlarmReceiver.class);
                PendingIntent sender = PendingIntent.getService(MainActivity.this, alarmKey, intent, 0);
                //PendingIntent sender = PendingIntent.getBroadcast(MainActivity.this, alarmKey, intent, 0);

                AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
                am.cancel(sender);// 取消闹铃

                Toast.makeText(MainActivity.this, "取消"+alarmKey+"号闹铃", Toast.LENGTH_LONG).show();

                //MainActivity.this.finish();
            }
        });
    }
}

AlarmService：



package fk.androiddemo_030;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.widget.Toast;

public class AlarmService extends Service {
    public AlarmService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        int alarmKey=intent.getIntExtra("alarmKey",-1);
        Toast.makeText(ContextUtil.getInstance(), alarmKey+"号闹铃响了, 可以做点事情了~~AlarmService", Toast.LENGTH_LONG).show();

        return super.onStartCommand(intent, flags, startId);
    }
}

AlarmReceiver：

package fk.androiddemo_030;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class AlarmReceiver extends BroadcastReceiver {
    public AlarmReceiver() {}

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO: This method is called when the BroadcastReceiver is receiving

        int alarmKey=intent.getIntExtra("alarmKey",-1);
        Toast.makeText(context, alarmKey+"号闹铃响了, 可以做点事情了~~AlarmReceiver", Toast.LENGTH_LONG).show();
    }
}

运行截图： 

随着生活和工作节奏的不断加快，每天大家要处理的事情越来越多，稍有不留意就很容易忘记重要的事情。为了避免忘记重要的事情，很多人的做法会在手机上设置一个闹钟，到点能准时提醒，但是使用闹钟设置提醒时，不能以文字的形式展示要提醒的内容，因此很多人又开始找手机上使用的带有闹钟提醒的记事本软件。
现如今随着智能手机的发展，几乎每一个品牌手机上都有自带的记事本软件，有些会以“便签”、“备忘录”命名，功能大同小异，都可用来记录每日待办事项，且可以设定闹铃提醒，能在固定的时间内提醒大家想要做的事情。
便签提醒
除了手机自带的记事本软件外，还可以在手机上安装第三方的记事本便签软件设置闹铃提醒，那么手机上下载哪个带有闹铃记事本的便签软件好用呢？小编今天给大家推荐一款叫敬业签的记事本便签软件。
敬业签是一款集提醒、记事和备忘于一体的便签软件，可以记录日常待办事项、行程约会等信息，且在记录内容时可以逐条进行梳理，每一条待办内容都支持设置闹铃提醒，敬业便签可设置按照公历或者农历日期进行单次定时提醒，还可设置按天/周/月/季/年周期循环提醒，还支持设定重要事项间隔时间提醒和到期延时提醒。
手机便签待办事项
通过查看便签上记录的待办事项可以理清每一项工作日程的轻重缓急，做好各项事务的管理工作。另外，敬业便签还支持绑定微信提醒、开启语音电话提醒、短信提醒、钉钉提醒、和邮箱提醒，多方位提醒大家按时完成待办事项，在便签软件的闹铃提醒下，大家可以提高做事的积极性，同时避免忘记重要的事情。

最近项目里有个功能，需要实现闹铃效果。

网上查了一大堆资料，都说要使用AlarmManager，AlarmManager使用起来倒是很简单。但App 一旦被杀了，就不起作用了……

然后又有好多可以让app存活的文章，奈何能在多款手机上，多种版本上都起作用的几乎没有……反正我在git上下载了几个demo都不行

在尝试了一整天还是不能达到效果之后，果断放弃了AlarmManager。然后继续在网上查询资料，终于发现了“日历事件”

通过向手机自带的日历中添加提醒事件，完美的实现了闹铃的效果！再也不用担心app在后台放久了，或者app被杀掉了这些让人头疼的问题了！