原文出處：http://blog.iderzheng.com/debug-activity-task-stack-with-adb-shell-dumpsys/

談起Android程序開(kāi)發(fā)，就需要了解其四個(gè)主要的部件：Activity、Service、ContentProvider、 BroadcastReceiver。而其中Activity是唯一直接控制程序界面呈現(xiàn)，直面用戶操作的部件（當(dāng)然BrowadCastReceiver也能通過(guò)桌面控件(App Widgets)來(lái)呈現(xiàn)有限的操作界面）。Android對(duì)于Activity有嚴(yán)格的生命周期控制，以限制開(kāi)發(fā)者在適當(dāng)?shù)幕卣{(diào)函數(shù)里的放上合適的代碼。對(duì)于多個(gè)Activity的轉(zhuǎn)換，Android也有非常好的管理和流暢的切換，對(duì)此Android還引入了任務(wù)棧(Task Stack)的概念，這個(gè)概念對(duì)于Android設(shè)備上得返回按鍵有極其重要的聯(lián)系。

大部分文檔都將其表述為T(mén)asks and Back Stack，但從官方文檔的描述來(lái)看，Android的相對(duì)于Activity講到的Task都視為一個(gè)存放Activities的Stack，所以將其稱為T(mén)ask Stack也不為過(guò)

在AndroidManifest中申明所要用到的Activity時(shí)可以設(shè)置不同的launchMode來(lái)得到不同的Activity“啟動(dòng)”效果。在使用startActivity開(kāi)啟新的Activity時(shí)，傳入的Intent也可以設(shè)置不同的Flag來(lái)達(dá)到不同的效果。另一方面，在Activity啟動(dòng)時(shí)它可能又開(kāi)啟了另一個(gè)Activity，或者調(diào)用了finish()函數(shù)終結(jié)了Activity。

這使得Activity棧變得無(wú)法掌握，有時(shí)候按下返回按鈕或者點(diǎn)擊關(guān)閉當(dāng)前Activity的操作，都不知道Android系統(tǒng)會(huì)把程序帶到那個(gè)Activity，不確定這是否是最后一個(gè)Activity以致退出了整個(gè)程序。亦或者一些按鈕和操作循環(huán)產(chǎn)生Activity而造成內(nèi)存膨脹。對(duì)于這些問(wèn)題，如果能夠在調(diào)試期間知道當(dāng)前任務(wù)棧的情況，就能很方便的觀察和發(fā)現(xiàn)問(wèn)題存在的原因，進(jìn)而選擇正確的launchMode，設(shè)置恰當(dāng)Intent的Flag來(lái)使程序達(dá)到預(yù)期的效果。

通過(guò)ActivityManager獲取狀態(tài)

Android提供了ActivityManger來(lái)幫助開(kāi)發(fā)者了解運(yùn)行期間的狀態(tài)，通過(guò)調(diào)用getRunningTasks(int)方法，就可以在得到RunningTaskInfo的列表，其代表著當(dāng)前Android設(shè)備正在運(yùn)行著的Task。從RunningTaskInfo中又可以進(jìn)一步得到更多的信息。

ActivityManager am = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE); List<RunningTaskInfo> runningTaskInfoList = am.getRunningTasks(10); for (RunningTaskInfo runningTaskInfo : runningTaskInfoList) {log("id: " + runningTaskInfo.id);log("description: " + runningTaskInfo.description);log("number of activities: " + runningTaskInfo.numActivities);log("topActivity: " + runningTaskInfo.topActivity);log("baseActivity: " + runningTaskInfo.baseActivity.toString()); }

例如文中提供的示例程序中定義了4個(gè)具有不同launchMode的Activity，每點(diǎn)擊一次菜單欄上得選項(xiàng)就會(huì)彈出一個(gè)新的Activity（或者將指定Singleton的Activity置前）。

Activity上顯示的數(shù)字則指示startActivity()被第幾次調(diào)用時(shí)開(kāi)啟了這個(gè)Activity。有一些Singleton的會(huì)顯示多個(gè)數(shù)字，也表明它是被復(fù)用的。

因?yàn)樵趏nCreate()方法上放置了上述代碼，所以觀察log就能發(fā)現(xiàn)當(dāng)前有多少個(gè)Task在被執(zhí)行，每個(gè)Task又有多少個(gè)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}

缺點(diǎn)

必須在程序中注入調(diào)試代碼，因?yàn)橐刂圃诎l(fā)布時(shí)代碼必須被清理了。RunningTaskInfo雖然能夠告訴我們有多少個(gè)Activity保存在其上，但是沒(méi)有提供完整的列表，只能看到頭尾兩個(gè)Activity。給出的兩個(gè)Activity的屬性：topActivity和baseActivity也只是ComponentName類型，并非真實(shí)的Activity對(duì)象，因此除了類的名字沒(méi)有其他更多信息。

手動(dòng)記錄和管理Activities棧

Activity的創(chuàng)建和銷毀都會(huì)有相應(yīng)的回調(diào)函數(shù)：onCreate()，onDestroy()。因此可以自建一個(gè)靜態(tài)全局Stack對(duì)象，在onCreate()時(shí)候講當(dāng)前Activity對(duì)象加入到Stack中，而在onDestroy()時(shí)把它從Stack中移除。這樣我們就隨時(shí)可以知道當(dāng)前Activity的詳細(xì)情況了。

缺點(diǎn)

要讓所有Activity的onCreate()和onDestroy()方法上有對(duì)應(yīng)的進(jìn)出棧的方法，要么有統(tǒng)一的基類，要么強(qiáng)制每個(gè)Activity都加入這些代碼，但兩種方式都不完美。另外也很難模擬singleTask這類會(huì)創(chuàng)建出新的Task的情況，這時(shí)光使用一個(gè)Stack就不足夠了，要考慮所有的情況又不太可能。再者如同使用ActivityManager一樣這些代碼也應(yīng)該只出現(xiàn)在調(diào)試階段

使用adb shell指令

Android還為開(kāi)發(fā)者提供了adb(Android Debug Bridge)，這是非常強(qiáng)大的調(diào)試工具。最常用的自然是logcat來(lái)顯示日志記錄。另外一個(gè)很強(qiáng)大的指令就是這里要提到的dumpsys。dumpsys還可以添加不同的參數(shù)來(lái)指示需要輸出哪一類Service的信息。對(duì)于本文提到的內(nèi)容，需要查看的就是activity，指令就是：

adb shell dumpsys activity

輸入上述指令，就能得到關(guān)于設(shè)備非常長(zhǎng)的一段訊息，單是也能清晰看出它們比較詳細(xì)的分類

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=trueauthority=icc... ... ... ...ACTIVITY MANAGER SERVICES (dumpsys activity services)User 0 active services:* ServiceRecord{429f8668 u0 com.android.bluetooth/.hid.HidService}app=nullcreated=-1h44m27s317ms started=false connections=0... ... ... ...ACTIVITY MANAGER ACTIVITIES (dumpsys activity activities)Stack #0:Task id #28TaskRecord{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)... ... ... ...

每一個(gè)類別都有一個(gè)括號(hào)內(nèi)容，給出了更加詳細(xì)的指令來(lái)查看該類別下更多具體內(nèi)容。因此再來(lái)嘗試指令：

db shell dumpsys activity activities

就能看到下邊的結(jié)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=trueintent={cmp=com.iderzheng/.SingleTaskActivity}realActivity=com.iderzheng/.SingleTaskActivityActivities=[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=falselastThumbnail=null lastDescription=nulllastActiveTime=6229735 (inactive for 357s)* Hist #4: ActivityRecord{4279d2d8 u0 com.iderzheng/.SingleTopActivity t25}packageName=com.iderzheng processName=com.iderzhenglaunchedFromUid=10124 launchedFromPackage=com.iderzheng userId=0app=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.iderzhengrealActivity=com.iderzheng/.SingleTopActivitybaseDir=/data/app/com.iderzheng-1.apkdataDir=/data/data/com.iderzhengstateNotNeeded=false componentSpecified=true mActivityType=0compat={320dpi} labelRes=0x7f0a0013 icon=0x7f020057 theme=0x7f0b0000config={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=-1h40m33s397mshaveState=false icicle=nullstate=RESUMED stopped=false delayedResume=false finishing=falsekeysPaused=false inHistory=true visible=true sleeping=false idle=truefullscreen=true noDisplay=false immersive=false launchMode=1frozenBeforeDestroy=false thumbnailNeeded=false forceNewConfig=falsemActivityType=APPLICATION_ACTIVITY_TYPEthumbHolder: 42b0ee20 bm=null desc=nullwaitingVisible=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:... ... ... ...

整個(gè)log顯示了當(dāng)前所有在運(yùn)行的任務(wù)棧，它們的id分別是什么。對(duì)于每個(gè)Task，也有Activity數(shù)量等信息，同時(shí)也列出了其中的Activity列表，并且對(duì)于每個(gè)Activity也有比較詳細(xì)的描述，比如啟動(dòng)它的Intent的內(nèi)容。

如果覺(jué)得內(nèi)容過(guò)多，只想看看棧的內(nèi)容，也可以直接跳到”Running activities (most recent first)”那部分，比較簡(jiǎn)潔而又明了的列出了棧中得Activity列表，就能知道當(dāng)按下返回鍵的時(shí)候會(huì)應(yīng)該會(huì)回到哪個(gè)Activity以后是要退出程序。

對(duì)于”Running activitie”s的內(nèi)容在dumpsys activity中就有，并不需要dumpsys activity activities，也可以用下邊的指令來(lái)限制僅輸出”Running activities”列表：

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

缺點(diǎn)

很明顯的看出，使用adb shell的相對(duì)于之前的方式的明顯好處就是不需要添加額外的代碼，而且任務(wù)棧的信息也更加詳盡。但是同樣的它只能輸出Activity的類名，對(duì)于具體屬性沒(méi)有記錄。

adb shell對(duì)于調(diào)試Android程序有很多的幫助，可惜對(duì)于adb指令都沒(méi)有比較全面詳細(xì)而又系統(tǒng)的教程。只能靠在實(shí)踐中慢慢摸索，從網(wǎng)上零星介紹中獲得。

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