1.IntentService

(1).介紹Service
Android中的Service是用于后臺服務(wù)的，當(dāng)應(yīng)用程序被掛起到后臺或者啟動Service的Activity被銷毀時，為了保證應(yīng)用某些組件仍然可以工作而引入了Service這個概念，但是Service既不是獨立的進(jìn)程，也不是獨立的線程，它是依賴于應(yīng)用程序的主線程的，在大部分時候不建議在Service中編寫耗時的邏輯和操作，否則會引起ANR。（阻塞主線程5s，會導(dǎo)致ANR）
(2).IntentService||JobIntentService應(yīng)用場景
如果我們編寫的耗時邏輯，不得不被service來管理的時候，就需要使用IntentService，IntentService是繼承Service的，那么它包含了Service的所有特性，當(dāng)然也包含service的生命周期，那么與service不同的是，IntentService在執(zhí)行onCreate操作的時候，內(nèi)部開了一個線程，去你執(zhí)行你的耗時操作。

public abstract class IntentService extends Service {
    protected abstract void onHandleIntent(@Nullable Intent intent);
   private final class ServiceHandler extends Handler {
        public ServiceHandler(Looper looper) {
            super(looper);
        }

        @Override
        public void handleMessage(Message msg) {
            onHandleIntent((Intent)msg.obj); //運行在子線程中
            stopSelf(msg.arg1);
        }
    }
   public void onCreate() {
        super.onCreate();
        HandlerThread thread = new HandlerThread("IntentService[" + mName + "]");
        thread.start();
        mServiceLooper = thread.getLooper();
        mServiceHandler = new ServiceHandler(mServiceLooper);
    }
   @Override
    public void onStart(@Nullable Intent intent, int startId) {
        Message msg = mServiceHandler.obtainMessage();
        msg.arg1 = startId;
        msg.obj = intent;
        mServiceHandler.sendMessage(msg);
    }
}

(3).繼承抽象類IntentService，然后實現(xiàn)handleIntent方法即可.

public  class TestService extends IntentService {
    public TestService(String name) {
        super(name);
    }
    @Override
    protected void onHandleIntent(@Nullable Intent intent) {
    }
}

(4).HandleThread實現(xiàn)
繼承了Thread，Looper.prepare()將當(dāng)前線程和Looper對象存儲到ThreadLocalMap中，然后提供getLooper方法。

public class HandlerThread extends Thread {
    public void run(){
      Looper.prepare();
        synchronized (this) {
            mLooper = Looper.myLooper();
            notifyAll();
        }
    }
   public Looper getLooper() {
      return mLooper;
   }
}

2.JobIntentService

(1).通過內(nèi)部的AysncTask來處理耗時操作

public abstract class JobIntentService extends Service {
     protected abstract void onHandleWork(@NonNull Intent intent);
      public int onStartCommand(@Nullable Intent intent, int flags, int startId) {
          ensureProcessorRunningLocked(true);
     }
     void ensureProcessorRunningLocked(boolean reportStarted) {
        if (mCurProcessor == null) {
            mCurProcessor = new CommandProcessor();
            if (mCompatWorkEnqueuer != null && reportStarted) {
                mCompatWorkEnqueuer.serviceProcessingStarted();
            }
            mCurProcessor.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
       }
    }
   final class CommandProcessor extends AsyncTask<Void, Void, Void> {
        protected Void doInBackground(Void... params) {
            GenericWorkItem work;

            if (DEBUG) Log.d(TAG, "Starting to dequeue work...");

            while ((work = dequeueWork()) != null) {
                if (DEBUG) Log.d(TAG, "Processing next work: " + work);
                 onHandleWork(work.getIntent());//回調(diào)onHandlerWork方法
                if (DEBUG) Log.d(TAG, "Completing work: " + work);
                work.complete();
            }
            return null;
        }
        @Override
        protected void onPostExecute(Void aVoid) {
            processorFinished();
        }
    }
}

(2).使用繼承抽象類JobIntentService，實現(xiàn)onHandleWork來處理耗時操作

public  class TestService extends JobIntentService {
    @Override 
    protected void onHandleWork(@NonNull Intent intent) { 
        //在AsyncTask啟動的異步線程中執(zhí)行
    }
}