四大组件之综述

frameworks/base/services/core/java/com/android/server/am/
  - ActivityManagerService.java
  - ProcessRecord
  - ActivityStackSupervisor.java
  - ActivityStack.java
  - ActiveServices
  - BroadcastQueue

<service android:name =".GityuanService"  android:process =":remote" >  
    <intent-filter>  
       <action android:name ="com.action.gityuan" />  
    </intent-filter>  
</service>

public final class ActivityManagerService extends ...{
    //当前聚焦的Activity
    ActivityRecord mFocusedActivity = null;
    //用于管理各个Activity栈
    final ActivityStackSupervisor mStackSupervisor;
}

public final class ActivityStackSupervisor implements DisplayListener {
    //桌面app所在栈
    ActivityStack mHomeStack;

    //当前可以接受Input事件，或许启动下一个Activity的栈
    ActivityStack mFocusedStack;

    //当该值等于mFocusedStack，代表当前栈顶的Activity已进入resumed状态；
    //当该值等于上一个旧栈时，代表正处理activity切换状态；
    private ActivityStack mLastFocusedStack;

    //在完成相应目标前，等待新的Activity成为可见的Activity列表
    final ArrayList<ActivityRecord> mWaitingVisibleActivities = new ArrayList<>();

    //等待找到下一个可见Activity的等待列表
    final ArrayList<IActivityManager.WaitResult> mWaitingActivityVisible = new ArrayList<>();

    //等待找到下一个已启动Activity的等待列表
    final ArrayList<IActivityManager.WaitResult> mWaitingActivityLaunched = new ArrayList<>();

    //等待上一个activity安置完成，则即将进入被stopped的Activity列表
    final ArrayList<ActivityRecord> mStoppingActivities = new ArrayList<>();

    //等待上一个activity安置完成，则即将进入被finished的Activity列表
    final ArrayList<ActivityRecord> mFinishingActivities = new ArrayList<>();

    //即将进入sleep状态的进程所对应的Activity列表
    final ArrayList<ActivityRecord> mGoingToSleepActivities = new ArrayList<>();
}

final class ActivityStack{
    //记录该栈中所有的task
    private final ArrayList<TaskRecord> mTaskHistory = new ArrayList<>();

    //按LRU方式排序的Activity列表，队尾成员是最新活动的Activity
    final ArrayList<ActivityRecord> mLRUActivities = new ArrayList<>();

    //正在执行pausing过程的Activity
    ActivityRecord mPausingActivity = null;

    //已处于paused状态的Activity
    ActivityRecord mLastPausedActivity = null;

    //已处于Resumed状态的Activity
    ActivityRecord mResumedActivity = null;
}

public final class ActiveServices {
    //记录不同User下所有的Service信息
    final SparseArray<ServiceMap> mServiceMap = new SparseArray<>();

    //bind service的连接信息，以IServiceConnection的Bp端作为Keys
    final ArrayMap<IBinder, ArrayList<ConnectionRecord>> mServiceConnections = new ArrayMap<>();

    //已请求启动但尚未启动的Service列表
    final ArrayList<ServiceRecord> mPendingServices = new ArrayList<>();

    //crash后需要计划重启的Service列表
    final ArrayList<ServiceRecord> mRestartingServices = new ArrayList<>();

    //正在执行destroyed的service列表
    final ArrayList<ServiceRecord> mDestroyingServices = new ArrayList<>();
}

public final class ActivityManagerService extends ...{
    //前台广播队列
    BroadcastQueue mFgBroadcastQueue;
    //后台广播队列
    BroadcastQueue mBgBroadcastQueue;
    //广播队列数组，也就是前台和后台广播队列
    final BroadcastQueue[] mBroadcastQueues = new BroadcastQueue[2];

    //粘性广播，[userId，action，ArrayList<Intent>]
    final SparseArray<ArrayMap<String, ArrayList<Intent>>> mStickyBroadcasts;

    //动态注册的广播接收者，其中key为客户端InnerReceiver的Bp端，value为ReceiverList
    final HashMap<IBinder, ReceiverList> mRegisteredReceivers = new HashMap<>();

    //从广播intent到已注册接收者的解析器
    final IntentResolver<BroadcastFilter, BroadcastFilter> mReceiverResolver；
}

public final class BroadcastQueue{
    //并行广播列表
    final ArrayList<BroadcastRecord> mParallelBroadcasts = new ArrayList<>();
    //串行广播列表
    final ArrayList<BroadcastRecord> mOrderedBroadcasts = new ArrayList<>();

    //即将要处理的串行广播，等待目标进程创建完成。每个广播队列只有一个，其他必须等待该广播完成。
    BroadcastRecord mPendingBroadcast = null;
}

public final class ActivityManagerService extends ...{
    //记录系统所有的provider信息
    final ProviderMap mProviderMap;

    //记录有client正在等待的provider列表，当provider发布完成则从该队列移除
    final ArrayList<ContentProviderRecord> mLaunchingProviders;
}

public final class ProviderMap {
    //以provider名字(auth)为key的方式所记录的provider信息
    private final HashMap<String, ContentProviderRecord> mSingletonByName;
    //以provider组件名(ComponentName)为key的方式所记录的provider信息
    private final HashMap<ComponentName, ContentProviderRecord> mSingletonByClass;

    //记录不同UserId下的，以auth为key的方式所记录的provider信息
    private final SparseArray<HashMap<String, ContentProviderRecord>> mProvidersByNamePerUser;
    //记录不同UserId下的，以ComponentName为key的方式所记录的provider信息
    private final SparseArray<HashMap<ComponentName, ContentProviderRecord>> mProvidersByClassPerUser;
}