gps啟動(dòng)流程

1、GPS啟動(dòng)流程及數(shù)據(jù)流向分析：首先在系統(tǒng)init階段，會(huì)通過(guò)ServiceManageraddService添加很多的Service，這其中就包含LocationService。代碼在SystemServer.java中:trySlog.i(TAG“LocationManager“)location=newLocationManagerService(context)ServiceManager.addService(Context.L

2、OCATION_SERVICElocation)catch(Throwablee)reptWtf(“startingLocationManager“e)隨后調(diào)用LocationManagerService的systemReady函數(shù)開(kāi)啟一個(gè)線程。finalLocationManagerServicelocationF=locationtryif(locationF!=null)locationF.systemReady()catch(T

3、hrowablee)reptWtf(“makingLocationServiceready“e)LocationManagerService.javavoidsystemReady()wedeferstartinguptheserviceuntilthesystemisreadyThreadthread=newThread(nullthis“LocationManagerService“)thread.start()在Thread的ru

4、n函數(shù)中為接收消息做好了準(zhǔn)備，并且調(diào)用了一個(gè)initialize函數(shù)：publicvoidrun()Process.setThreadPriity(Process.THREAD_PRIITY_BACKGROUND)Looper.prepare()mLocationHler=newLocationWkerHler()initialize()Looper.loop()接著看initialize()：privatevoidinitialize

5、()CreateawakelockneedstobedonebefecallingloadProvidesynchronized(mLock)updateProvidersLocked()privatevoidupdateProvidersLocked()booleanchangesMade=falsef(inti=mProviders.size()1i=0i)LocationProviderInterfacep=mProviders.

6、get(i)booleanisEnabled=p.isEnabled()Stringname=p.getName()booleanshouldBeEnabled=isAllowedBySettingsLocked(name)If(isEnabledchangesMade=trueelseif(!isEnabledchangesMade=trueif(changesMade)mContext.sendBroadcast(newIntent

7、(LocationManager.PROVIDERS_CHANGED_ACTION))privatevoidupdateProviderListenersLocked(Stringproviderbooleanenabled)intlisteners=0LocationProviderInterfacep=mProvidersByName.get(provider)if(p==null)returnArrayListdeadReceiv