Android Service类与生命周期详细介绍

public class MyService extends Service {  // 必须实现，绑定该Service时被回调  @Override  public IBinder onBind(Intent intent) {    return null;  }  // Service被创建时回调  @Override  public void onCreate() {    super.onCreate();    // 定义相关业务逻辑    System.out.println("Service is Created");  }  // Service被启动时回调  @Override  public int onStartCommand(Intent intent, int flags, int startId) {    // 定义相关业务逻辑    System.out.println("Service is Started");    return START_STICKY;  }  // Service被关闭之前回调  @Override  public void onDestroy() {    super.onDestroy();    System.out.println("Service is Destroyed");  }}

<application  ...  <!-- 配置一个Service组件 -->  <service android:name=".MyService">    <intent-filter>      <!-- 为该Service组件的intent-filter配置action -->      <action android:name="com.gc.service.MY_SERVICE" />    </intent-filter>  </service></application>

// 创建启动Service的Intentfinal Intent intent = new Intent();// 为Intent设置Action属性intent.setAction("com.gc.service.MY_SERVICE");...// 启动指定SerivcestartService(intent);...// 停止指定SerivcestopService(intent);

bindService(Intent intent, ServiceConnection conn, int flags)，三个参数如下：intent：指定要启动的Serviceconn：用于监听访问者与Service之间的连接情况，当访问者与Service之间连接成功时将回调该ServiceConnection对象的onServiceConnected(ComponentName name, IBinder service)方法；反之回调该ServiceConnection对象的onServiceDisconnected(ComponentName name)方法（主动调用unbindService方法断开连接时则不回调）flags：指定绑定时是否创建Service，0：不自动创建；BIND_AUTO_CREATE:自动创建注意：ServiceConnection对象的onServiceConnected方法中有一个IBinder对象，该对象即可实现与绑定Service之间的通信。在绑定本地Service的情况下，onBind(Intent intent)方法所返回的IBinder对象将会传给ServiceConnection对象里onServiceConnected(ComponentName name, IBinder service)方法的service参数，这样访问者就可以通过该IBinder对象与Service进行通信。

public class MyService extends Service {  private int count;  // 定义onBinder方法所返回的对象  private MyBinder binder = new MyBinder();  // 通过继承Binder来实现IBinder类  public class MyBinder extends Binder {    public int getCount() {      return count; // 获取Service的运行状态    }  }  // 必须实现，绑定该Service时被回调  @Override  public IBinder onBind(Intent intent) {    System.out.println("Service is Binded");    return binder; // 返回IBinder对象  }  // Service被创建时回调  @Override  public void onCreate() {    super.onCreate();    System.out.println("Service is Created");    count = 100;  }  // Service被断开连接时回调  @Override  public boolean onUnbind(Intent intent) {    System.out.println("Service is Unbinded");    return true;  }  // Service被关闭之前回调  @Override  public void onDestroy() {    super.onDestroy();    System.out.println("Service is Destroyed");  }}

public class MyServiceTest extends Activity {  // Service的IBinder对象  MyService.MyBinder binder;  // 定义一个ServiceConnection对象  private ServiceConnection conn = new ServiceConnection() {    // 当该Activity与Service连接成功时回调    @Override    public void onServiceConnected(ComponentName name, IBinder service) {      // 获取Service的onBind方法所返回的MyBinder对象      binder = (MyService.MyBinder) service;    }    // 当该Activity与Service断开连接时回调    @Override    public void onServiceDisconnected(ComponentName name) {    }  };  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    ...    // 创建启动Service的Intent    final Intent intent = new Intent();    // 为Intent设置Action属性    intent.setAction("com.gc.service.MY_SERVICE");    // 绑定指定Serivce    bindService(intent, conn, Service.BIND_AUTO_CREATE);    ...    binder.getCount(); // 获取Serivce的count值    ...       // 解除绑定Serivce    unbindService(conn);  }}