Android开发源码解读四大组件源码解读简单梳理

Android开发四大组件源码解读简单梳理

1. Activity启动流程

//主进程-main
Activity.startActivity()
mInstrumentation.execStartActivity()
ActivityTaskManager.getService().startActivity()
    - final IBinder b = ServiceManager.getService(Context.ACTIVITY_TASK_SERVICE);
    - return IActivityTaskManager.Stub.asInterface(b);
//准备Stack有关的，新的binder进程-AMS
ActivityTaskManagerService.startActivity()
getActivityStartController().obtainStarter()...execute();//...组装Request()，接着执行
ActivityStarter.executeRequest(Request request);//启动器执行Request,添加Activity到ActivityStack
    - ActivityRecord r = new ActivityRecord()
    - startActivityUnchecked()
    - startActivityInner() 
    - addOrReparentStartingActivity();//parent.addChild(mStartActivity)添加Activity到ActivityStack
    - mTargetStack.getStack().moveToFront("reuseOrNewTask", targetTask);
ActivityStack.startActivityLocked() //执行stack逻辑，比如判断是否显示前一个Activity窗口过程等等
ActivityRecord.showStartingWindow() //执行当前Activity的show window逻辑

//可能需要新进程，比如第一次启动进程还不存在
ActivityStarter.startActivityInner()
    RootWindowContainer.resumeFocusedStacksTopActivities()
        //如果新进程,则增加下面三个逻辑异步创建进程
        - ActivityStack.resumeTopActivityUncheckedLocked()
        - ActivityStack.resumeTopActivityInnerLocked
        - mAtmService.startProcessAsync(); //mAtmService是ActivityTaskManagerService
        - ActivityManagerInternal::startProcess //创建进程
        - ActivityManagerService::LocalService::startProcess()  //最好还是回到AMS内部类
        - ProcessList.startProcessLocked()
        - ProcessList.startProcess()
        - Process.start(entryPoint,...) //entryPoint就是“android.app.ActivityThread ”
    mSupervisor.mRecentTasks.add(mStartActivity.getTask());//最后添加到最近任务列表

//准备窗口有关的，这里东西比较多，也比较底层，涉及到Display、Surface、WmService等等
ActivityTaskManagerService.continueWindowLayout()
DisplayContent、DisplayManagerService
mWmService.mDisplayManagerInternal.performTraversal(mDisplayTransaction);

//Activity生命周期有关的，底层Binder-AMS发送各种和生命周期有关的Transaction与主线程ActivityThread交互
ClientTransactionHandler.scheduleTransaction()
ActivityThread(extends ClientTransactionHandler).sendMessage()
    - ActivityThread.mH.sendMessage(msg);
    - mTransactionExecutor.execute(transaction);//LaunchActivityItem
LaunchActivityItem.execute()
    - client.handleLaunchActivity(r, pendingActions, null);
    - ActivityThread.performLaunchActivity()

1. Service启动流程

//main
Context.startService()
ContextImpl.startServiceCommon()
//AMS
ActivityManager.getService().startService()
ActivityManagerService.startService()
ActiveServices.startServiceLocked() //ActiveServices管理Service启动关闭，前后台，启动是否超时等等
  - startServiceInnerLocked
  - bringUpServiceLocked
  - realStartServiceLocked
  - app.thread.scheduleCreateService()//ApplicationThread
//main
ApplicationThread.scheduleCreateService()
  - sendMessage(H.CREATE_SERVICE, s);
  - ActivityThread.handleCreateService()

1. Broadcast接收与发送广播流程

//main
Context.registerReceiver()
ContextImpl.registerReceiverInternal()
LoadedApk.getReceiverDispatcher() //获取Dispatcher，保存Receiver
  - ReceiverDispatcher.performReceive()
//AMS
ActivityManager.getService().registerReceiverWithFeature()
  - rl = new ReceiverList(this, callerApp, callingPid, callingUid, userId, receiver);
  - mRegisteredReceivers.put(receiver.asBinder(), rl);  //AMS的mRegisteredReceivers保存封装的接收者列表
  - BroadcastFilter bf = new BroadcastFilter(filter, rl, callerPackage, ...);
  - rl.add(bf);

//main
Context.sendBroadcast
ContextImpl.sendBroadcast
//AMS
ActivityManager.getService().broadcastIntentWithFeature()
ActivityManagerService.broadcastIntentWithFeature()
ActivityManagerService.broadcastIntentLocked()
  - BroadcastRecord r = new BroadcastRecord()
  - queue.enqueueOrderedBroadcastLocked(r);
  - ActivityManagerService持有三类广播，前台广播，后台广播，离线广播
    BroadcastQueue mFgBroadcastQueue; //是否为前台广播通过Intent的flag指定
      BroadcastQueue mBgBroadcastQueue; //默认是后台广播
      BroadcastQueue mOffloadBroadcastQueue;  //比如BOOT_COMPLETED广播
      mStickyBroadcasts //粘性广播使用SparseArray保存
BroadcastQueue.scheduleBroadcastsLocked() //Handler转发一次
BroadcastQueue.processNextBroadcast()
BroadcastQueue.deliverToRegisteredReceiverLocked()
BroadcastQueue.performReceiveLocked()
  - app.thread.scheduleRegisteredReceiver()
LoadedApk.performReceive()
  - Handler.post(args.getRunnable())
  - receiver.onReceive(mContext, intent);

1. ContentProvider初始化流程

//main
ActivityThread.main(String[] args)
ActivityThread.attach(false, startSeq)
  - mgr = ActivityManager.getService(); mgr.attachApplication(mAppThread, startSeq);
//AMS
ActivityManagerService.attachApplication(IApplicationThread thread, long startSeq)
ActivityManagerService.attachApplicationLocked(IApplicationThread thread,...)
  - generateApplicationProvidersLocked()//通过PMS获取xml注册的ContentProvider组件
  - thread.bindApplication(processName, appInfo, providerList)//将解析的provider信息传递给主进程
//main
ActivityThread.bindApplication()
  - sendMessage(H.BIND_APPLICATION, data);
ActivityThread.handleBindApplication(data);
ActivityThread.installContentProviders(app, data.providers)
  - for (ProviderInfo cpi : providers)
  - installProvider(context, null, cpi,false, true, true);
ContentProvider.attachInfo()
  - ContentProvider.this.onCreate();  //ContentProvider的初始化是在Application之前哦。。。

//main
ContentResolver.insert()
ContentProvider.acquireProvider()
ActivityThread.acquireExistingProvider()//获取ContentProviderProxy代理类
ContentProviderProxy.insert() //binder通信mRemote.transact -> onTransact
ContentProviderNative.insert()