Android ActivityManagerService总结(三)Activity管理相关数据结构

不念不忘少年蓝@ 2024-03-24 13:25 15阅读 0赞

## 一. 前言 ##

接上一篇文章 [AMS组成][AMS] , 介绍了一下AMS的内部数据结构, ProcessRecord容器,还有四大组件记录表 , 本篇文章继续讲解一下与Activity管理相关的数据结构, 重点关注如下4个类文件:ActivityRecord TaskRecord ActivityStack ActivityStackSupervisor

基本概念:

*  ActivityRecord: 记录着Activity信息
 *  TaskRecord: 记录着task信息
 *  ActivityStack: 栈信息
 *  ActivityStackSupervisor : 栈管理者

## 二. ActivityRecord ##

ActivityRecord，源码中的注释介绍：An entry in the history stack, representing an activity.翻译：历史栈中的一个条目，代表一个activity.

final class ActivityRecord extends ConfigurationContainer {
    ....
        final ActivityTaskManagerService mAtmService; // owner
        final IApplicationToken.Stub appToken; // window manager token
        
         final ActivityInfo info; // all about me
        // TODO: This is duplicated state already contained in info.applicationInfo - remove
        ApplicationInfo appInfo; // information about activity's app
    
        //ActivityRecord所在的TaskRecord
        TaskRecord task;        // the task this is in.
    
        //ActivityRecord的构造方法, 需要传递大量的信息
        ActivityRecord(ActivityTaskManagerService _service, WindowProcessController _caller,
                int _launchedFromPid, int _launchedFromUid, String _launchedFromPackage, Intent _intent,
                String _resolvedType, ActivityInfo aInfo, Configuration _configuration,
                ActivityRecord _resultTo, String _resultWho, int _reqCode, boolean _componentSpecified,
                boolean _rootVoiceInteraction, ActivityStackSupervisor supervisor,
                ActivityOptions options, ActivityRecord sourceRecord) {
            mAtmService = _service;
            mRootActivityContainer = _service.mRootActivityContainer;
            appToken = new Token(this, _intent);
            info = aInfo;
            launchedFromPid = _launchedFromPid;
            launchedFromUid = _launchedFromUid;
            launchedFromPackage = _launchedFromPackage;
            mUserId = UserHandle.getUserId(aInfo.applicationInfo.uid);
            intent = _intent;
            shortComponentName = _intent.getComponent().flattenToShortString();
            resolvedType = _resolvedType;
            componentSpecified = _componentSpecified;
            rootVoiceInteraction = _rootVoiceInteraction;
            mLastReportedConfiguration = new MergedConfiguration(_configuration);
            resultTo = _resultTo;
            resultWho = _resultWho;
            requestCode = _reqCode;
            //省略剩下的参数
    
    ....
    }

ActivityRecord中存在着大量的成员变量，包含了一个Activity的所有信息。  
**ActivityRecord中的成员变量task表示其所在的TaskRecord**，由此可以看出：**ActivityRecord与TaskRecord建立了联系.**

列举出重要的成员变量

<table style="width:680px;"> 
 <thead> 
  <tr> 
   <th style="width:82px;">序号</th> 
   <th style="width:232px;">成员变量</th> 
   <th style="width:365px;">描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="width:82px;">1</td> 
   <td style="width:232px;">ProcessRecord app</td> 
   <td style="width:365px;">运行在哪个进程</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">2</td> 
   <td style="width:232px;">TaskRecord task</td> 
   <td style="width:365px;">运行在哪个task</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">3</td> 
   <td style="width:232px;">ActivityInfo info</td> 
   <td style="width:365px;">Activity的信息</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">4</td> 
   <td style="width:232px;">int mActivityType</td> 
   <td style="width:365px;">Activity类型</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">5</td> 
   <td style="width:232px;">ActivityState state</td> 
   <td style="width:365px;">Activity的状态</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">6</td> 
   <td style="width:232px;">ApplicationInfo appInfo</td> 
   <td style="width:365px;">运行在哪个app中</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">7</td> 
   <td style="width:232px;">ComponentName realActivity</td> 
   <td style="width:365px;">组件名</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">8</td> 
   <td style="width:232px;">String packageName</td> 
   <td style="width:365px;">包名</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">9</td> 
   <td style="width:232px;">String processName</td> 
   <td style="width:365px;">进程名</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">10</td> 
   <td style="width:232px;">int launchMode</td> 
   <td style="width:365px;">启动模式</td> 
  </tr> 
  <tr> 
   <td style="width:82px;">11</td> 
   <td style="width:232px;">int userId&nbsp;</td> 
   <td style="width:365px;">该Activity运行在哪个用户id</td> 
  </tr> 
 </tbody> 
</table>

Activity类型

/** Activity type is currently not defined.  未定义类型*/
        public static final int ACTIVITY_TYPE_UNDEFINED = 0;
    
        /**标准Activity类型 Standard activity type. Nothing special about the activity... */
        public static final int ACTIVITY_TYPE_STANDARD = 1;
    
        /** 桌面类型 Home/Launcher activity type. */
        public static final int ACTIVITY_TYPE_HOME = 2;
    
        /** 最近任务类型  Recents/Overview activity type. There is only one activity with this type in the system. */
        public static final int ACTIVITY_TYPE_RECENTS = 3;
    
        /** 辅助Activity类型Assistant activity type. */
        public static final int ACTIVITY_TYPE_ASSISTANT = 4;

Activity的状态ActivityState

enum ActivityState {
            INITIALIZING,
            RESUMED,     //已恢复
            PAUSING,
            PAUSED,      //已暂停
            STOPPING, 
            STOPPED,     //已停止
            FINISHING,
            DESTROYING,
            DESTROYED,   //已销毁
            RESTARTING_PROCESS
        }

时间相关的成员变量：

<table> 
 <thead> 
  <tr> 
   <th>时间点</th> 
   <th>赋值时间</th> 
   <th>含义</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>createTime</td> 
   <td>new ActivityRecord</td> 
   <td>Activity首次创建时间点</td> 
  </tr> 
  <tr> 
   <td>displayStartTime</td> 
   <td>AS.setLaunchTime</td> 
   <td>Activity首次启动时间点</td> 
  </tr> 
  <tr> 
   <td>fullyDrawnStartTime</td> 
   <td>AS.setLaunchTime</td> 
   <td>Activity首次启动时间点</td> 
  </tr> 
  <tr> 
   <td>startTime</td> 
   <td></td> 
   <td>Activity上次启动的时间点</td> 
  </tr> 
  <tr> 
   <td>lastVisibleTime</td> 
   <td>AR.windowsVisibleLocked</td> 
   <td>Activity上次成为可见的时间点</td> 
  </tr> 
  <tr> 
   <td>cpuTimeAtResume</td> 
   <td>AS.completeResumeLocked</td> 
   <td>从Rsume以来的cpu使用时长</td> 
  </tr> 
  <tr> 
   <td>pauseTime</td> 
   <td>AS.startPausingLocked</td> 
   <td>Activity上次暂停的时间点</td> 
  </tr> 
  <tr> 
   <td>launchTickTime</td> 
   <td>AR.startLaunchTickingLocked</td> 
   <td>Eng版本才赋值</td> 
  </tr> 
  <tr> 
   <td>lastLaunchTime</td> 
   <td>ASS.realStartActivityLocked</td> 
   <td>上一次启动时间</td> 
  </tr> 
 </tbody> 
</table>

其中AR是指ActivityRecord, AS是指ActivityStack。

## 三. TaskRecord ##

Task的信息记录在TaskRecord对象.

TaskRecord，内部维护一个 ArrayList<ActivityRecord> 用来保存ActivityRecord。  
frameworks/base/services/core/java/com/android/server/am/TaskRecord.java

final int taskId;       // Unique identifier for this task. 任务ID
     /** List of all activities in the task arranged in history order */
     //使用一个ArrayList来保存所有的ActivityRecord
     final ArrayList<ActivityRecord> mActivities;
     //TaskRecord所在的ActivityStack
     private ActivityStack mStack; 
    
    
    
    //构造方法
    TaskRecord(ActivityTaskManagerService service, int _taskId, ActivityInfo info, Intent _intent,
                IVoiceInteractionSession _voiceSession, IVoiceInteractor _voiceInteractor) {
            mService = service;
            userId = UserHandle.getUserId(info.applicationInfo.uid);
            taskId = _taskId;
            lastActiveTime = SystemClock.elapsedRealtime();
            mAffiliatedTaskId = _taskId;
            voiceSession = _voiceSession;
            voiceInteractor = _voiceInteractor;
            isAvailable = true;
            mActivities = new ArrayList<>();
            mCallingUid = info.applicationInfo.uid;
            mCallingPackage = info.packageName;
            setIntent(_intent, info);
            setMinDimensions(info);
            touchActiveTime();
            mService.getTaskChangeNotificationController().notifyTaskCreated(_taskId, realActivity);
        }

列出重要的成员变量信息

<table style="width:680px;"> 
 <thead> 
  <tr> 
   <th style="width:82px;">序号</th> 
   <th style="width:232px;">成员变量</th> 
   <th style="width:365px;">描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>1</td> 
   <td>ActivityStack stack</td> 
   <td>当前所属的stack</td> 
  </tr> 
  <tr> 
   <td>2</td> 
   <td>ArrayList mActivities</td> 
   <td>当前task的所有Activity列表</td> 
  </tr> 
  <tr> 
   <td>3</td> 
   <td>int taskId</td> 
   <td>taskID</td> 
  </tr> 
  <tr> 
   <td>4</td> 
   <td>String affinity</td> 
   <td>是指root activity的affinity，即该Task中第一个Activity;</td> 
  </tr> 
  <tr> 
   <td>5</td> 
   <td>int mCallingUid</td> 
   <td>调用者的UID</td> 
  </tr> 
  <tr> 
   <td>6</td> 
   <td>String mCallingPackage</td> 
   <td>调用者的包名</td> 
  </tr> 
 </tbody> 
</table>

## 四. ActivityStack ##

ActivityStack,内部维护了一个 ArrayList<TaskRecord> ，用来管理TaskRecord

class ActivityStack extends ConfigurationContainer {
    .....
       /**
         * The back history of all previous (and possibly still
         * running) activities.  It contains #TaskRecord objects.
         */
        // 使用一个ArrayList来保存TaskRecord
        private final ArrayList<TaskRecord> mTaskHistory = new ArrayList<>();
        //持有一个 ActivityStackSupervisor，所有的运行中的ActivityStacks都通过它来进行管
        protected final ActivityStackSupervisor mStackSupervisor;
    
        
        //构造方法
        TaskRecord createTaskRecord(int taskId, ActivityInfo info, Intent intent,
                IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor,
                boolean toTop, ActivityRecord activity, ActivityRecord source,
                ActivityOptions options) {
            //创建一个task
            final TaskRecord task = TaskRecord.create(
                    mService, taskId, info, intent, voiceSession, voiceInteractor);
            // add the task to stack first, mTaskPositioner might need the stack association
            //将task添加到ActivityStack中去
            addTask(task, toTop, "createTaskRecord");
            final int displayId = mDisplayId != INVALID_DISPLAY ? mDisplayId : DEFAULT_DISPLAY;
            final boolean isLockscreenShown = mService.mStackSupervisor.getKeyguardController()
                    .isKeyguardOrAodShowing(displayId);
            if (!mStackSupervisor.getLaunchParamsController()
                    .layoutTask(task, info.windowLayout, activity, source, options)
                    && !matchParentBounds() && task.isResizeable() && !isLockscreenShown) {
                task.updateOverrideConfiguration(getRequestedOverrideBounds());
            }
            task.createTask(toTop, (info.flags & FLAG_SHOW_FOR_ALL_USERS) != 0);
            return task;
        }
    
        //添加Task到指定位置
        void addTask(final TaskRecord task, int position, boolean schedulePictureInPictureModeChange,
                String reason) {
            // TODO: Is this remove really needed? Need to look into the call path for the other addTask
            //若存在，先移除
            mTaskHistory.remove(task);
            if (isSingleTaskInstance() && !mTaskHistory.isEmpty()) {
                throw new IllegalStateException("Can only have one child on stack=" + this);
            }
    
            position = getAdjustedPositionForTask(task, position, null /* starting */);
            final boolean toTop = position >= mTaskHistory.size();
            final ActivityStack prevStack = preAddTask(task, reason, toTop);
            //添加task到mTaskHistory
            mTaskHistory.add(position, task);
            //为TaskRecord设置ActivityStack
            task.setStack(this);
    
            updateTaskMovement(task, toTop);
    
            postAddTask(task, prevStack, schedulePictureInPictureModeChange);
        }
    ....
    }

可以看到ActivityStack使用了一个ArrayList来保存TaskRecord。  
另外，ActivityStack中还持有ActivityStackSupervisor对象，这个是用来管理ActivityStacks的。  
ActivityStack是由ActivityStackSupervisor来创建的，实际ActivityStackSupervisor就是用来管理  
ActivityStack的.

列出重要的成员变量信息

<table style="width:680px;"> 
 <thead> 
  <tr> 
   <th style="width:84px;">序号</th> 
   <th style="width:179px;">成员变量</th> 
   <th style="width:416px;">描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="width:84px;">1</td> 
   <td style="width:179px;">ArrayList mTaskHistory</td> 
   <td style="width:416px;">保存所有的Task列表</td> 
  </tr> 
  <tr> 
   <td style="width:84px;">2</td> 
   <td style="width:179px;">ArrayList mStacks</td> 
   <td style="width:416px;">所有stack列表</td> 
  </tr> 
  <tr> 
   <td style="width:84px;">3</td> 
   <td style="width:179px;">int mStackId</td> 
   <td style="width:416px;">栈ID</td> 
  </tr> 
  <tr> 
   <td style="width:84px;">4</td> 
   <td style="width:179px;">int mDisplayId</td> 
   <td style="width:416px;">affinity附加的显示器的唯一标识符，如果已分离，则为-1</td> 
  </tr> 
  <tr> 
   <td style="width:84px;">5</td> 
   <td style="width:179px;">ActivityRecord mPausingActivity</td> 
   <td style="width:416px;">正在pause状态的ActivityRecord</td> 
  </tr> 
  <tr> 
   <td style="width:84px;">6</td> 
   <td style="width:179px;">ActivityRecord mLastPausedActivity</td> 
   <td style="width:416px;">最后pause状态ActivityRecord</td> 
  </tr> 
  <tr> 
   <td style="width:84px;">7</td> 
   <td style="width:179px;">ActivityRecord mResumedActivity</td> 
   <td style="width:416px;">已经resumed Activity的ActivityRecord对象</td> 
  </tr> 
 </tbody> 
</table>

所有前台stack的mResumedActivity的state == RESUMED, 则表示allResumedActivitiesComplete, 此时mLastFocusedStack = mFocusedStack;

## 五. ActivityStackSupervisor ##

ActivityStackSupervisor，顾名思义，就是用来管理ActivityStack的  
frameworks/base/services/core/java/com/android/server/wm/ActivityDisplay.java

class ActivityDisplay extends ConfigurationContainer<ActivityStack>
            implements WindowContainerListener {
    ....
        //管理的是Launcher相关的任务
        private ActivityStack mHomeStack = null; 
        //管理的是Recent相关的任务栈
        private ActivityStack mRecentsStack = null;
        //画中画的任务栈
        private ActivityStack mPinnedStack = null;
        //分屏模式下的主屏幕栈
        private ActivityStack mSplitScreenPrimaryStack = null;
    ....
    }

## 六. Activity栈关系 ##

Activity栈结构体的组成关系: [点击查看大图][Link 1]

*  一般地，对于没有分屏功能以及虚拟屏的情况下，ActivityStackSupervisor与ActivityDisplay都是系统唯一；
 *  ActivityDisplay主要有Home Stack和App Stack这两个栈；
 *  每个ActivityStack中可以有若干个TaskRecord对象；
 *  每个TaskRecord包含如果个ActivityRecord对象；
 *  每个ActivityRecord记录一个Activity信息。

(1)正向关系链表：

1.  `ActivityStackSupervisor.mActivityDisplays`
2.  `-> ActivityDisplay.mStacks`
3.  `-> ActivityStack.mTaskHistory`
4.  `-> TaskRecord.mActivities`
5.  `-> ActivityRecord`

(2)反向关系链表：

1.  `ActivityRecord.task`
2.  `-> TaskRecord.stack`
3.  `-> ActivityStack.mStackSupervisor`
4.  `-> ActivityStackSupervisor`

注：ActivityStack.mDisplayId可找到所对应的ActivityDisplay；

## 七. 参考文章 ##

[四大组件之ActivityRecord][ActivityRecord]

[AMS：ActivityRecord 理解 ][AMS_ActivityRecord _]

##  ##

[AMS]: https://blog.csdn.net/u012514113/article/details/129908501
[Link 1]: http://gityuan.com/images/ams/activity/ams_relations.jpg
[ActivityRecord]: https://blog.csdn.net/b1480521874/article/details/84637592
[AMS_ActivityRecord _]: https://blog.csdn.net/hejnhong/article/details/127477444