无法开始service 啊代码全部附上

public class AActivity extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        Intent intent=new Intent(this,AService.class);        startService(intent);    }}

public class AService extends Service {    @Override    public void onCreate() {        super.onCreate();        System.out.println("create");    }    @Override    public IBinder onBind(Intent intent) {        return null;    }    @Override    public void onDestroy() {        super.onDestroy();        System.out.println("destroy");    }    @Override    public void onStart(Intent intent, int startId) {        super.onStart(intent, startId);        System.out.println("start");    }}

<manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="yjc.a" android:versionCode="1" android:versionName="1.0">    <uses-sdk android:minSdkVersion="10" />    <application android:icon="@drawable/icon" android:label="@string/app_name">        <activity android:name=".AActivity" 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=".AService" android:enabled="true" />            </application>    </manifest>