Android后台定时提醒功能实现

import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.Window; import android.widget.Toast;  public class MainActivity extends Activity {   private Intent intent;  @Override  protected void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   //取消标题栏   requestWindowFeature(Window.FEATURE_NO_TITLE);   //由于主要是用于测试，并且便于新手理解，所以activity_main布局写的很简单   setContentView(R.layout.activity_main);   intent = new Intent(this, LongRunningService.class);   //开启关闭Service   startService(intent);    //设置一个Toast来提醒使用者提醒的功能已经开始   Toast.makeText(MainActivity.this,"提醒的功能已经开启，关闭界面则会取消提醒。",Toast.LENGTH_LONG).show();  }   @Override  protected void onDestroy() {   super.onDestroy();   //在Activity被关闭后，关闭Service   stopService(intent);  } } 

import android.app.AlarmManager; import android.app.PendingIntent; import android.app.Service; import android.content.Intent; import android.os.IBinder; import android.os.SystemClock;  public class LongRunningService extends Service {    @Override  public IBinder onBind(Intent intent) {   return null;  }   @Override  public int onStartCommand(Intent intent, int flags, int startId) {    AlarmManager manager = (AlarmManager) getSystemService(ALARM_SERVICE);   //读者可以修改此处的Minutes从而改变提醒间隔时间   //此处是设置每隔90分钟启动一次   //这是90分钟的毫秒数   int Minutes = 90*60*1000;   //SystemClock.elapsedRealtime()表示1970年1月1日0点至今所经历的时间   long triggerAtTime = SystemClock.elapsedRealtime() + Minutes;   //此处设置开启AlarmReceiver这个Service   Intent i = new Intent(this, AlarmReceiver.class);   PendingIntent pi = PendingIntent.getBroadcast(this, 0, i, 0);   //ELAPSED_REALTIME_WAKEUP表示让定时任务的出发时间从系统开机算起，并且会唤醒CPU。   manager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, triggerAtTime, pi);   return super.onStartCommand(intent, flags, startId);  }   @Override  public void onDestroy() {   super.onDestroy();    //在Service结束后关闭AlarmManager   AlarmManager manager = (AlarmManager) getSystemService(ALARM_SERVICE);   Intent i = new Intent(this, AlarmReceiver.class);   PendingIntent pi = PendingIntent.getBroadcast(this, 0, i, 0);   manager.cancel(pi);   } } 

import android.app.Notification; import android.app.NotificationManager; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent;  public class AlarmReceiver extends BroadcastReceiver {   @Override  public void onReceive(Context context, Intent intent) {   //设置通知内容并在onReceive()这个函数执行时开启   NotificationManager manager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);   Notification notification=new Notification(R.drawable.ic_launcher,"用电脑时间过长了！白痴！"   ,System.currentTimeMillis());   notification.setLatestEventInfo(context, "快去休息！！！",     "一定保护眼睛,不然遗传给孩子，老婆跟别人跑啊。", null);   notification.defaults = Notification.DEFAULT_ALL;   manager.notify(1, notification);     //再次开启LongRunningService这个服务，从而可以   Intent i = new Intent(context, LongRunningService.class);   context.startService(i);  }   } 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:padding="15dp"  android:orientation="vertical"  >   <TextView   android:layout_marginBottom="20dp"   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:text="护眼定时提醒"   android:textSize="30sp"   android:gravity="center_horizontal"   />     <TextView   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:text="提醒间隔时间:"   android:textSize="25sp"   />   <TextView   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:text="90分钟"   android:textSize="25sp"   />   <TextView   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:text="提醒音乐："   android:textSize="25sp"   />  <TextView   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:text="系统默认音乐"   android:textSize="25sp"   /> </LinearLayout> 

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"  package="com.example.servicebestpractice"  android:versionCode="1"  android:versionName="1.0" >   <uses-sdk   android:minSdkVersion="14"   android:targetSdkVersion="17" />   <application   android:allowBackup="true"   android:icon="@drawable/ic_launcher"   android:label="@string/app_name"   android:theme="@style/AppTheme" >   <activity    android:name="com.example.servicebestpractice.MainActivity"    android:label="@string/app_name" >    <intent-filter>     <action android:name="android.intent.action.MAIN" />      <category android:name="android.intent.category.LAUNCHER" />    </intent-filter>   </activity>    <service android:name=".LongRunningService" >   </service>    <receiver android:name=".AlarmReceiver" >   </receiver>  </application>  </manifest>