正如文档所说,我正在努力理解intetService是如何在单个后台线程中完成所有工作的。所以我深入研究源代码,并有一个问题
public abstract class IntentService extends Service {
private volatile Looper mServiceLooper;
private volatile ServiceHandler mServiceHandler;
private String mName;
private boolean mRedelivery;
private final class ServiceHandler extends Handler {
public ServiceHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
onHandleIntent((Intent)msg.obj);
stopSelf(msg.arg1);
}
}
/**
* Creates an IntentService. Invoked by your subclass's constructor.
*
* @param name Used to name the worker thread, important only for debugging.
*/
public IntentService(String name) {
super();
mName = name;
}
public void setIntentRedelivery(boolean enabled) {
mRedelivery = enabled;
}
@Override
public void onCreate() {
// TODO: It would be nice to have an option to hold a partial wakelock
// during processing, and to have a static startService(Context, Intent)
// method that would launch the service & hand off a wakelock.
super.onCreate();
HandlerThread thread = new HandlerThread("IntentService[" + mName + "]");
thread.start();
mServiceLooper = thread.getLooper();
mServiceHandler = new ServiceHandler(mServiceLooper);
}
@Override
public void onStart(Intent intent, int startId) {
Message msg = mServiceHandler.obtainMessage();
msg.arg1 = startId;
msg.obj = intent;
mServiceHandler.sendMessage(msg);
}
/**
* You should not override this method for your IntentService. Instead,
* override {@link #onHandleIntent}, which the system calls when the IntentService
* receives a start request.
* @see android.app.Service#onStartCommand
*/
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
onStart(intent, startId);
return mRedelivery ? START_REDELIVER_INTENT : START_NOT_STICKY;
}
@Override
public void onDestroy() {
mServiceLooper.quit();
}
因此,在onCreate服务中创建了一个HandlerThread。之后,所有onStartCommand调用都会将消息添加到HanlderThread队列中
但假设服务接收到多个意向,并将所有意向添加到队列中。但在处理第一条消息后,handleMessage中onHandleIntent之后的下一个调用是stopSelf(消息arg1)。据我所知,在这之后,服务被破坏,但HandlerThread继续处理消息。在摧毁之后,假设我再发送一个意向服务。由于意图服务被破坏,此调用onCreate并创建另一个HandlerThread,在那之后就没有了几个Worker线程,不像文档中所说的Single。有人能解释一下我错在哪里吗?
据我所知,在这之后,的服务被破坏了
没有。如果您呼叫stopSelf()
,服务将停止。但是,只有在没有其他未完成的Intents
已交付给该服务的情况下,stopSelf(int)
才会停止该服务。