AlarmManager定时重复任务，发送心跳

package com.example.alarm_1;

import android.app.Activity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = new Intent();
intent.setClass(MainActivity.this, MyService.class);

PendingIntent pendingIntent = PendingIntent.getService(this, 0, intent,
0);

AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
Log.i("Alarm", "Alarm");
// am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + 5*1000,
// pendingIntent);  ///单次不重复

 am.setRepeating(AlarmManager.RTC_WAKEUP ,
 System.currentTimeMillis(), 10*1000, pendingIntent);//////TTTT   重复
//am.setInexactRepeating(AlarmManager.RTC_WAKEUP,
//System.currentTimeMillis(), 10 * 1000, pendingIntent);////TTTT  重复

}
}

package com.example.alarm_1;import java.util.Date;import android.app.Service;import android.content.Intent;import android.media.MediaPlayer;import android.os.IBinder;import android.util.Log;import android.widget.Toast;/** * @author Administrator *  */public class MyService extends Service {@Overridepublic IBinder onBind(Intent intent) {// TODO 自动生成的方法存根return null;}@Overridepublic void onCreate() {// TODO 自动生成的方法存根}@Overridepublic void onStart(Intent intent, int startId) {// TODO 自动生成的方法存根try {Thread.sleep(5000);} catch (InterruptedException e) {// TODO 自动生成的 catch 块e.printStackTrace();}// player.stop();Log.i("--------------------暂停----------------------", "暂停");Toast.makeText(this, "暂停", Toast.LENGTH_SHORT).show();}@Overridepublic void onDestroy() {// TODO 自动生成的方法存根}}// / class MyService

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="${relativePackage}.${activityClass}" >    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" /></RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.alarm_1"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="15"
        android:targetSdkVersion="16" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".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=".MyService"
            android:enabled="true" >
        </service>
    </application>

</manifest>

效果是：每隔10s执行一次服务，延迟5s后显示“暂停”提示，循环发生。这个有大作用，这5s可以访问数据库，往里写数据，或者保持在线状态，