使用adb shell dumpsys检测Android的Activity任务栈

谈起Android程序开发,就需要了解其四个主要的部件ActivityServiceContentProvider、 BroadcastReceiver。而其中Activity是唯一直接控制程序界面呈现,直面用户操作的部件(当然BrowadCastReceiver也能通过桌面控件(App Widgets)来呈现有限的操作界面)。Android对于Activity有严格的生命周期控制,以限制开发者在适当的回调函数里的放上合适的代码。对于多个Activity的转换,Android也有非常好的管理和流畅的切换,对此Android还引入了任务栈(Task Stack)的概念,这个概念对于Android设备上得返回按键有极其重要的联系。

(大部分文档都将其表述为Tasks and Back Stack,但从官方文档的描述来看,Android的相对于Activity讲到的Task都视为一个存放Activities的Stack,所以将其称为Task Stack也不为过。)

在AndroidManifest中申明所要用到的Activity时可以设置不同的launchMode来得到不同的Activity“启动”效果。在使用startActivity开启新的Activity时,传入的Intent也可以设置不同的Flag来达到不同的效果。另一方面,在Activity启动时它可能又开启了另一个Activity,或者调用了finish()函数终结了Activity。

这使得Activity栈变得无法掌握,有时候按下返回按钮或者点击关闭当前Activity的操作,都不知道Android系统会把程序带到那个Activity,不确定这是否是最后一个Activity以致退出了整个程序。亦或者一些按钮和操作循环产生Activity而造成内存膨胀。对于这些问题,如果能够在调试期间知道当前任务栈的情况,就能很方便的观察和发现问题存在的原因,进而选择正确的launchMode,设置恰当IntentFlag来使程序达到预期的效果。

 

通过ActivityManager获取状态

Android提供了ActivityManger来帮助开发者了解运行期间的状态,通过调用getRunningTasks(int)方法,就可以在得到RunningTaskInfo的列表,其代表着当前Android设备正在运行着的Task。从RunningTaskInfo中又可以进一步得到更多的信息。

  1. ActivityManager am = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
  2. List<RunningTaskInfo> runningTaskInfoList = am.getRunningTasks(10);
  3. for (RunningTaskInfo runningTaskInfo : runningTaskInfoList) {
  4. log("id: " + runningTaskInfo.id);
  5. log("description: " + runningTaskInfo.description);
  6. log("number of activities: " + runningTaskInfo.numActivities);
  7. log("topActivity: " + runningTaskInfo.topActivity);
  8. log("baseActivity: " + runningTaskInfo.baseActivity.toString());
  9. }

例如文中提供的示例程序中定义了4个具有不同launchMode的Activity,每点击一次菜单栏上得选项就会弹出一个新的Activity(或者将指定Singleton的Activity置前)。
技术分享
Activity上显示的数字则指示startActivity()被第几次调用时开启了这个Activity。有一些Singleton的会显示多个数字,也表明它是被复用的。
技术分享
因为在onCreate()方法上放置了上述代码,所以观察log就能发现当前有多少个Task在被执行,每个Task又有多少个Activities。

D/IDER    ( 3700): =====================
D/IDER    ( 3700): ---------------------
D/IDER    ( 3700): id: 25
D/IDER    ( 3700): description: null
D/IDER    ( 3700): number of activities: 4
D/IDER    ( 3700): topActivity: ComponentInfo{com.iderzheng/com.iderzheng.StandardActivity}
D/IDER    ( 3700): baseActivity: ComponentInfo{com.iderzheng/com.iderzheng.SingleTaskActivity}
D/IDER    ( 3700): ---------------------
D/IDER    ( 3700): id: 24
D/IDER    ( 3700): description: null
D/IDER    ( 3700): number of activities: 1
D/IDER    ( 3700): topActivity: ComponentInfo{com.iderzheng/com.iderzheng.SingleInstanceActivity}
D/IDER    ( 3700): baseActivity: ComponentInfo{com.iderzheng/com.iderzheng.SingleInstanceActivity}
D/IDER    ( 3700): ---------------------
D/IDER    ( 3700): id: 23
D/IDER    ( 3700): description: null
D/IDER    ( 3700): number of activities: 2
D/IDER    ( 3700): topActivity: ComponentInfo{com.iderzheng/com.iderzheng.StandardActivity}
D/IDER    ( 3700): baseActivity: ComponentInfo{com.iderzheng/com.iderzheng.MainActivity}
D/IDER    ( 3700): ---------------------
D/IDER    ( 3700): id: 1
D/IDER    ( 3700): description: null
D/IDER    ( 3700): number of activities: 1
D/IDER    ( 3700): topActivity: ComponentInfo{com.android.launcher/com.android.launcher2.Launcher}
D/IDER    ( 3700): baseActivity: ComponentInfo{com.android.launcher/com.android.launcher2.Launcher}

缺点

必须在程序中注入调试代码,因为要控制在发布时代码必须被清理了。RunningTaskInfo虽然能够告诉我们有多少个Activity保存在其上,但是没有提供完整的列表,只能看到头尾两个Activity。给出的两个Activity的属性:topActivity和baseActivity也只是ComponentName类型,并非真实的Activity对象,因此除了类的名字没有其他更多信息。

手动记录和管理Activities栈

Activity的创建和销毁都会有相应的回调函数:onCreate()onDestroy()。因此可以自建一个静态全局Stack对象,在onCreate()时候讲当前Activity对象加入到Stack中,而在onDestroy()时把它从Stack中移除。这样我们就随时可以知道当前Activity的详细情况了。

缺点

要让所有Activity的onCreate()onDestroy()方法上有对应的进出栈的方法,要么有统一的基类,要么强制每个Activity都加入这些代码,但两种方式都不完美。另外也很难模拟singleTask这类会创建出新的Task的情况,这时光使用一个Stack就不足够了,要考虑所有的情况又不太可能。再者如同使用ActivityManager一样这些代码也应该只出现在调试阶段

使用adb shell指令

Android还为开发者提供了adb(Android Debug Bridge),这是非常强大的调试工具。最常用的自然是logcat来显示日志记录。另外一个很强大的指令就是这里要提到的dumpsysdumpsys还可以添加不同的参数来指示需要输出哪一类Service的信息。对于本文提到的内容,需要查看的就是activity,指令就是:

adb shell dumpsys activity


输入上述指令,就能得到关于设备非常长的一段讯息,单是也能清晰看出它们比较详细的分类

 

ACTIVITY MANAGER PENDING INTENTS (dumpsys activity intents)
  * PendingIntentRecord{42b05f20 com.android.vending startService}
  ... ... ... ...

ACTIVITY MANAGER BROADCAST STATE (dumpsys activity broadcasts)
  Historical broadcasts [foreground]:
  #0: BroadcastRecord{430d2fb8 u-1 android.intent.action.TIME_TICK}
    act=android.intent.action.TIME_TICK flg=0x50000014 (has extras)
    extras: Bundle[{android.intent.extra.ALARM_COUNT=1}]
  ... ... ... ...

ACTIVITY MANAGER CONTENT PROVIDERS (dumpsys activity providers)
  Published single-user content providers (by class):
  * ContentProviderRecord{429d18a8 u0 com.android.phone/.IccProvider}
    proc=ProcessRecord{429765d8 858:com.android.phone/1001}
    singleton=true
    authority=icc
  ... ... ... ...

ACTIVITY MANAGER SERVICES (dumpsys activity services)
  User 0 active services:
  * ServiceRecord{429f8668 u0 com.android.bluetooth/.hid.HidService}
    app=null
    created=-1h44m27s317ms started=false connections=0
  ... ... ... ...

ACTIVITY MANAGER ACTIVITIES (dumpsys activity activities)
  Stack #0:
    Task id #28
      TaskRecord{43525058 #28 A=com.android.systemui U=0 sz=1}
      Intent { act=com.android.systemui.recent.action.TOGGLE_RECENTS flg=0x10c00000 cmp=com.android.systemui/.recent.RecentsActivity (has extras) }
        Hist #0: ActivityRecord{428d1ae8 u0 com.android.systemui/.recent.RecentsActivity t28}
          Intent { act=com.android.systemui.recent.action.TOGGLE_RECENTS flg=0x10800000 cmp=com.android.systemui/.recent.RecentsActivity bnds=[328,886][656,1176] }
          ProcessRecord{42968230 695:com.android.systemui/u0a12}
  ... ... ... ...

ACTIVITY MANAGER RUNNING PROCESSES (dumpsys activity processes)
  Process LRU list (sorted by oom_adj, 28 total, non-act at 3, non-svc at 3):
    PERS #27: sys   F/ /P  trm: 0 605:system/1000 (fixed)
  ... ... ... ...

每一个类别都有一个括号内容,给出了更加详细的指令来查看该类别下更多具体内容。因此再来尝试指令:

db shell dumpsys activity activities

就能看到下边的结果

CTIVITY MANAGER ACTIVITIES (dumpsys activity activities)
  Stack #0:
    Task id #28
    * TaskRecord{43525058 #28 A=com.android.systemui U=0 sz=1}
      ... ... ... ...
      * Hist #0: ActivityRecord{428d1ae8 u0 com.android.systemui/.recent.RecentsActivity t28}
          ... ... ... ...
    Task id #1
    * TaskRecord{429a35f8 #1 A=com.android.launcher U=0 sz=1}
      ... ... ... ...
      * Hist #0: ActivityRecord{429a1760 u0 com.android.launcher/com.android.launcher2.Launcher t1}
          ... ... ... ...

    Running activities (most recent first):
      TaskRecord{43525058 #28 A=com.android.systemui U=0 sz=1}
        Run #1: ActivityRecord{428d1ae8 u0 com.android.systemui/.recent.RecentsActivity t28}
      TaskRecord{429a35f8 #1 A=com.android.launcher U=0 sz=1}
        Run #0: ActivityRecord{429a1760 u0 com.android.launcher/com.android.launcher2.Launcher t1}

    mLastPausedActivity: ActivityRecord{428d1ae8 u0 com.android.systemui/.recent.RecentsActivity t28}

  Stack #1:
    Task id #25
    * TaskRecord{42b0ee20 #25 I=com.iderzheng/.SingleTaskActivity U=0 sz=5}
      numActivities=5 rootWasReset=false userId=0 mTaskType=0 numFullscreen=5 mOnTopOfHome=true
      intent={cmp=com.iderzheng/.SingleTaskActivity}
      realActivity=com.iderzheng/.SingleTaskActivity
      Activities=[ActivityRecord{42a7e160 u0 com.iderzheng/.SingleTaskActivity t25}, ActivityRecord{42bffdf0 u0 com.iderzheng/.StandardActivity t25}, ActivityRecord{42e9e8f8 u0 com.iderzheng/.SingleTopActivity t25}, ActivityRecord{434c2238 u0 com.iderzheng/.StandardActivity t25}, ActivityRecord{4279d2d8 u0 com.iderzheng/.SingleTopActivity t25}]
      askedCompatMode=false
      lastThumbnail=null lastDescription=null
      lastActiveTime=6229735 (inactive for 357s)
      * Hist #4: ActivityRecord{4279d2d8 u0 com.iderzheng/.SingleTopActivity t25}
          packageName=com.iderzheng processName=com.iderzheng
          launchedFromUid=10124 launchedFromPackage=com.iderzheng userId=0
          app=ProcessRecord{4312cbb0 3700:com.iderzheng/u0a124}
          Intent { cmp=com.iderzheng/.SingleTopActivity bnds=[328,580][656,870] }
          frontOfTask=false task=TaskRecord{42b0ee20 #25 I=com.iderzheng/.SingleTaskActivity U=0 sz=5}
          taskAffinity=com.iderzheng
          realActivity=com.iderzheng/.SingleTopActivity
          baseDir=/data/app/com.iderzheng-1.apk
          dataDir=/data/data/com.iderzheng
          stateNotNeeded=false componentSpecified=true mActivityType=0
          compat={320dpi} labelRes=0x7f0a0013 icon=0x7f020057 theme=0x7f0b0000
          config={1.0 310mcc?mnc en_US ldltr sw384dp w384dp h567dp 320dpi nrml port finger -keyb/v/h -nav/h s.7}
          launchFailed=false launchCount=0 lastLaunchTime=-1h40m33s397ms
          haveState=false icicle=null
          state=RESUMED stopped=false delayedResume=false finishing=false
          keysPaused=false inHistory=true visible=true sleeping=false idle=true
          fullscreen=true noDisplay=false immersive=false launchMode=1
          frozenBeforeDestroy=false thumbnailNeeded=false forceNewConfig=false
          mActivityType=APPLICATION_ACTIVITY_TYPE
          thumbHolder: 42b0ee20 bm=null desc=null
          waitingVisible=false nowVisible=true lastVisibleTime=-5m56s862ms
    ... ... ... ...

    Running activities (most recent first):
      TaskRecord{42b0ee20 #25 I=com.iderzheng/.SingleTaskActivity U=0 sz=5}
        Run #7: ActivityRecord{4279d2d8 u0 com.iderzheng/.SingleTopActivity t25}
      TaskRecord{429e9558 #24 A=com.iderzheng U=0 sz=1}
        Run #6: ActivityRecord{429d5408 u0 com.iderzheng/.SingleInstanceActivity t24}
      TaskRecord{42b0ee20 #25 I=com.iderzheng/.SingleTaskActivity U=0 sz=5}
        Run #5: ActivityRecord{434c2238 u0 com.iderzheng/.StandardActivity t25}
        Run #4: ActivityRecord{42e9e8f8 u0 com.iderzheng/.SingleTopActivity t25}
        Run #3: ActivityRecord{42bffdf0 u0 com.iderzheng/.StandardActivity t25}
        Run #2: ActivityRecord{42a7e160 u0 com.iderzheng/.SingleTaskActivity t25}
      TaskRecord{4282e508 #23 A=com.iderzheng U=0 sz=2}
        Run #1: ActivityRecord{429655d8 u0 com.iderzheng/.StandardActivity t23}
        Run #0: ActivityRecord{429564e0 u0 com.iderzheng/.MainActivity t23}
 
  ... ... ... ...

  Recent tasks:
  ... ... ... ...

整个log显示了当前所有在运行的任务栈,它们的id分别是什么。对于每个Task,也有Activity数量等信息,同时也列出了其中的Activity列表,并且对于每个Activity也有比较详细的描述,比如启动它的Intent的内容。

如果觉得内容过多,只想看看栈的内容,也可以直接跳到”Running activities (most recent first)”那部分,比较简洁而又明了的列出了栈中得Activity列表,就能知道当按下返回键的时候会应该会回到哪个Activity以后是要退出程序。

对于”Running activitie”s的内容在dumpsys activity中就有,并不需要dumpsys activity activities,也可以用下边的指令来限制仅输出”Running activities”列表:

adb shell dumpsys activity activities | sed -En -e ‘/Running activities/,/Run #0/p‘

缺点

很明显的看出,使用adb shell的相对于之前的方式的明显好处就是不需要添加额外的代码,而且任务栈的信息也更加详尽。但是同样的它只能输出Activity的类名,对于具体属性没有记录。

 

adb shell对于调试Android程序有很多的帮助,可惜对于adb指令都没有比较全面详细而又系统的教程。只能靠在实践中慢慢摸索,从网上零星介绍中获得。

Download Source Code for Testing

References:
  1. Android Debug Bridge | Android Developers
  2. How to know which activities are running in Android | The skiing cube
  3. Wrightrocket: Using dumpsys commands in the Android adb shell
  4. activity – How to find back stack activities in an android application? – Stack Overflow
  5. What’s Android ADB shell ‘dumpsys’ tool and it’s benefits? – Stack Overflow

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