为什么我的标准 Activity 没有在 Android 中新实例化（结果 START_DELIVERED_TO_TOP）？

问题描述 投票：0回答：1

我的应用程序中有两个活动：.

  • 主要活动
  • 第二次活动

它们都是默认的LAUNCH MODE，根据我的理解应该是STANDARD模式。

第1步：现在我通过

adb shell am start -n com.study.launch/.MainActivity
命令启动MainActivity，任务堆栈变成：

* [0] MainAcitivty

这是正常的，因为正如预期的那样，创建了一个新的 MainActivity 实例。

第2步：然后我使用命令

adb shell am start -n com.study.launch/.SecondActivity
启动SecondActivity，任务堆栈变为：

* [1] SecondAcitivty
* [0] MainAcitivty

这是正常的，因为正如预期的那样，创建了 SecondActivity 的新实例，并且由于 Affnity 默认为应用程序的包名称，因此它被放入同一个任务中，尽管在启动时设置了 NEW TASK FLAG。

第 3 步：然后我使用 

adb shell am start -n com.study.launch/.SecondActivity
命令再次启动 SecondActivity，任务堆栈变为：

* [2] SecondAcitivty
* [1] SecondAcitivty
* [0] MainAcitivity

这是正常的，因为正如预期的那样，创建了 SecondActivity 的新实例。

第 4 步：最后，我使用命令 

adb shell am start -n com.study.launch/.MainActivity
再次启动 MainActivity。结果我给了我一个警告：

Starting: Intent { cmp=com.study.launch/.MainActivity }
Warning: Activity not started, intent has been delivered to currently running top-most instance.

检查任务堆栈，仍然成立：

* [2] SecondAcitivty
* [1] SecondAcitivty
* [0] MainAcitivity

我的问题：为什么没有创建 MainActivity 的新实例？

此时转储活动时，任务堆栈为：

ACTIVITY MANAGER ACTIVITIES (dumpsys activity activities)
Display #0 (activities from top to bottom):
  Stack #2970: type=standard mode=fullscreen
  isSleeping=false
  mBounds=Rect(0, 0 - 0, 0)
    mResumedActivity: ActivityRecord{4165bf9 u0 com.study.launch/.SecondActivity t2970}
    * Task{e640079 #2970 visible=true type=standard mode=fullscreen translucent=false A=10353:com.study.launch U=0 StackId=2970 sz=3}
      mBounds=Rect(0, 0 - 0, 0)
      mMinWidth=-1 mMinHeight=-1
      userId=0 effectiveUid=u0a353 mCallingUid=2000 mUserSetupComplete=true mCallingPackage=com.android.shell mCallingFeatureId=null
      affinity=10353:com.study.launch
      intent={flg=0x10000000 cmp=com.study.launch/.MainActivity}
      mActivityComponent=com.study.launch/.MainActivity
      autoRemoveRecents=false isPersistable=true activityType=1
      rootWasReset=false mNeverRelinquishIdentity=true mReuseTask=false mLockTaskAuth=LOCK_TASK_AUTH_PINNABLE
      Activities=[ActivityRecord{bcbe940 u0 com.study.launch/.MainActivity t2970}, ActivityRecord{be1bac4 u0 com.study.launch/.SecondActivity t2970}, ActivityRecord{4165bf9 u0 com.study.launch/.SecondActivity t2970}]
      askedCompatMode=false inRecents=true isAvailable=true
      mRootProcess=ProcessRecord{f26596c 18860:com.study.launch/u0a353}
      taskId=2970 stackId=2970
      mHasBeenVisible=true
      mResizeMode=RESIZE_MODE_RESIZEABLE_VIA_SDK_VERSION mSupportsPictureInPicture=false isResizeable=true
      lastActiveTime=932630195 (inactive for 208s)
      * Hist #2: ActivityRecord{4165bf9 u0 com.study.launch/.SecondActivity t2970}
          packageName=com.study.launch processName=com.study.launch
          launchedFromUid=2000 launchedFromPackage=com.android.shell launchedFromFeature=null userId=0
          app=ProcessRecord{f26596c 18860:com.study.launch/u0a353}
          Intent { flg=0x10000000 cmp=com.study.launch/.SecondActivity }
          rootOfTask=false task=Task{e640079 #2970 visible=true type=standard mode=fullscreen translucent=false A=10353:com.study.launch U=0 StackId=2970 sz=3}
          taskAffinity=10353:com.study.launch
          mActivityComponent=com.study.launch/.SecondActivity
          baseDir=/data/app/~~16sf25MRe03beHbyI0Sc3g==/com.study.launch-SSF_oypq9Ln-G52kGNzmdw==/base.apk
          dataDir=/data/user/0/com.study.launch
          stateNotNeeded=false componentSpecified=false mActivityType=standard
          compat={560dpi} labelRes=0x7f090055 icon=0x7f080001 theme=0x7f0a000a
          mLastReportedConfigurations:
            mGlobalConfig={1.0 ?mcc?mnc [zh_CN] ldltr sw411dp w411dp h659dp 560dpi nrml port finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 1440, 2560) mAppBounds=Rect(0, 0 - 1440, 2392) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=undefined mAlwaysOnTop=undefined mRotation=ROTATION_0} s.61}
            mOverrideConfig={1.0 ?mcc?mnc [zh_CN] ldltr sw411dp w411dp h659dp 560dpi nrml port finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 1440, 2560) mAppBounds=Rect(0, 0 - 1440, 2392) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=standard mAlwaysOnTop=undefined mRotation=ROTATION_0} s.1}
          CurrentConfiguration={1.0 ?mcc?mnc [zh_CN] ldltr sw411dp w411dp h659dp 560dpi nrml port finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 1440, 2560) mAppBounds=Rect(0, 0 - 1440, 2392) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=standard mAlwaysOnTop=undefined mRotation=ROTATION_0} s.1}
          taskDescription: label="null" icon=null iconResource=/0 iconFilename=null primaryColor=fff5f5f5
            backgroundColor=fffafafa statusBarColor=0 navigationBarColor=0
          launchFailed=false launchCount=1 lastLaunchTime=-3m28s587ms
          mHaveState=false mIcicle=null
          state=RESUMED stopped=false delayedResume=false finishing=false
          keysPaused=false inHistory=true setToSleep=false idle=true mStartingWindowState=STARTING_WINDOW_NOT_SHOWN
          occludesParent=true noDisplay=false immersive=false launchMode=0
          frozenBeforeDestroy=false forceNewConfig=false
          mActivityType=standard
          windows=[Window{ef30aec u0 com.study.launch/com.study.launch.SecondActivity}]
          windowType=2 hasVisible=true
          mOccludesParent=true mOrientation=-1
          mVisibleRequested=true mVisible=true mClientVisible=true reportedDrawn=true reportedVisible=true
          mNumInterestingWindows=1 mNumDrawnWindows=1 allDrawn=true lastAllDrawn=true)
          startingData=null firstWindowDrawn=true mIsExiting=false
          nowVisible=true lastVisibleTime=-3m28s54ms
          resizeMode=RESIZE_MODE_RESIZEABLE_VIA_SDK_VERSION
          mLastReportedMultiWindowMode=false mLastReportedPictureInPictureMode=false
      * Hist #1: ActivityRecord{be1bac4 u0 com.study.launch/.SecondActivity t2970}
          packageName=com.study.launch processName=com.study.launch
          launchedFromUid=2000 launchedFromPackage=com.android.shell launchedFromFeature=null userId=0
          app=ProcessRecord{f26596c 18860:com.study.launch/u0a353}
          Intent { flg=0x10000000 cmp=com.study.launch/.SecondActivity }
          rootOfTask=false task=Task{e640079 #2970 visible=true type=standard mode=fullscreen translucent=false A=10353:com.study.launch U=0 StackId=2970 sz=3}
          taskAffinity=10353:com.study.launch
          mActivityComponent=com.study.launch/.SecondActivity
          baseDir=/data/app/~~16sf25MRe03beHbyI0Sc3g==/com.study.launch-SSF_oypq9Ln-G52kGNzmdw==/base.apk
          dataDir=/data/user/0/com.study.launch
          stateNotNeeded=false componentSpecified=false mActivityType=standard
          compat={560dpi} labelRes=0x7f090055 icon=0x7f080001 theme=0x7f0a000a
          mLastReportedConfigurations:
            mGlobalConfig={1.0 ?mcc?mnc [zh_CN] ldltr sw411dp w411dp h659dp 560dpi nrml port finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 1440, 2560) mAppBounds=Rect(0, 0 - 1440, 2392) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=undefined mAlwaysOnTop=undefined mRotation=ROTATION_0} s.61}
            mOverrideConfig={1.0 ?mcc?mnc [zh_CN] ldltr sw411dp w411dp h659dp 560dpi nrml port finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 1440, 2560) mAppBounds=Rect(0, 0 - 1440, 2392) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=standard mAlwaysOnTop=undefined mRotation=ROTATION_0} s.1}
          CurrentConfiguration={1.0 ?mcc?mnc [zh_CN] ldltr sw411dp w411dp h659dp 560dpi nrml port finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 1440, 2560) mAppBounds=Rect(0, 0 - 1440, 2392) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=standard mAlwaysOnTop=undefined mRotation=ROTATION_0} s.1}
          taskDescription: label="null" icon=null iconResource=/0 iconFilename=null primaryColor=fff5f5f5
            backgroundColor=fffafafa statusBarColor=0 navigationBarColor=0
          launchFailed=false launchCount=0 lastLaunchTime=-4m48s99ms
          mHaveState=true mIcicle=Bundle[mParcelledData.dataSize=1380]
          state=STOPPED stopped=true delayedResume=false finishing=false
          keysPaused=false inHistory=true setToSleep=false idle=true mStartingWindowState=STARTING_WINDOW_NOT_SHOWN
          occludesParent=true noDisplay=false immersive=false launchMode=0
          frozenBeforeDestroy=false forceNewConfig=false
          mActivityType=standard
          windows=[Window{4792473 u0 com.study.launch/com.study.launch.SecondActivity}]
          windowType=2 hasVisible=true
          mOccludesParent=true mOrientation=-1
          mVisibleRequested=false mVisible=false mClientVisible=false reportedDrawn=false reportedVisible=false
          mAppStopped=true
          mNumInterestingWindows=1 mNumDrawnWindows=1 allDrawn=true lastAllDrawn=true)
          startingData=null firstWindowDrawn=true mIsExiting=false
          nowVisible=false lastVisibleTime=-4m47s573ms
          resizeMode=RESIZE_MODE_RESIZEABLE_VIA_SDK_VERSION
          mLastReportedMultiWindowMode=false mLastReportedPictureInPictureMode=false
      * Hist #0: ActivityRecord{bcbe940 u0 com.study.launch/.MainActivity t2970}
          packageName=com.study.launch processName=com.study.launch
          launchedFromUid=2000 launchedFromPackage=com.android.shell launchedFromFeature=null userId=0
          app=ProcessRecord{f26596c 18860:com.study.launch/u0a353}
          Intent { flg=0x10000000 cmp=com.study.launch/.MainActivity }
          rootOfTask=true task=Task{e640079 #2970 visible=true type=standard mode=fullscreen translucent=false A=10353:com.study.launch U=0 StackId=2970 sz=3}
          taskAffinity=10353:com.study.launch
          mActivityComponent=com.study.launch/.MainActivity
          baseDir=/data/app/~~16sf25MRe03beHbyI0Sc3g==/com.study.launch-SSF_oypq9Ln-G52kGNzmdw==/base.apk
          dataDir=/data/user/0/com.study.launch
          stateNotNeeded=false componentSpecified=false mActivityType=standard
          compat={560dpi} labelRes=0x7f090001 icon=0x7f080001 theme=0x7f0a000a
          mLastReportedConfigurations:
            mGlobalConfig={1.0 ?mcc?mnc [zh_CN] ldltr sw411dp w411dp h659dp 560dpi nrml port finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 1440, 2560) mAppBounds=Rect(0, 0 - 1440, 2392) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=undefined mAlwaysOnTop=undefined mRotation=ROTATION_0} s.61}
            mOverrideConfig={1.0 ?mcc?mnc [zh_CN] ldltr sw411dp w411dp h659dp 560dpi nrml port finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 1440, 2560) mAppBounds=Rect(0, 0 - 1440, 2392) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=standard mAlwaysOnTop=undefined mRotation=ROTATION_0} s.1}
          CurrentConfiguration={1.0 ?mcc?mnc [zh_CN] ldltr sw411dp w411dp h659dp 560dpi nrml port finger -keyb/v/h -nav/h winConfig={ mBounds=Rect(0, 0 - 1440, 2560) mAppBounds=Rect(0, 0 - 1440, 2392) mWindowingMode=fullscreen mDisplayWindowingMode=fullscreen mActivityType=standard mAlwaysOnTop=undefined mRotation=ROTATION_0} s.1}
          taskDescription: label="null" icon=null iconResource=/0 iconFilename=null primaryColor=fff5f5f5
            backgroundColor=fffafafa statusBarColor=0 navigationBarColor=0
          launchFailed=false launchCount=0 lastLaunchTime=-5m43s524ms
          mHaveState=true mIcicle=Bundle[mParcelledData.dataSize=1380]
          state=STOPPED stopped=true delayedResume=false finishing=false
          keysPaused=false inHistory=true setToSleep=false idle=true mStartingWindowState=STARTING_WINDOW_REMOVED
          occludesParent=true noDisplay=false immersive=false launchMode=0
          frozenBeforeDestroy=false forceNewConfig=false
          mActivityType=standard
          windows=[Window{76c0bff u0 com.study.launch/com.study.launch.MainActivity}]
          windowType=2 hasVisible=true
          mOccludesParent=true mOrientation=-1
          mVisibleRequested=false mVisible=false mClientVisible=false reportedDrawn=false reportedVisible=false
          mAppStopped=true
          mNumInterestingWindows=1 mNumDrawnWindows=1 allDrawn=true lastAllDrawn=true)
          startingData=null firstWindowDrawn=true mIsExiting=false
          nowVisible=false lastVisibleTime=-5m41s774ms
          resizeMode=RESIZE_MODE_RESIZEABLE_VIA_SDK_VERSION
          mLastReportedMultiWindowMode=false mLastReportedPictureInPictureMode=false

另外，我发现如果应用程序的第一次启动（进程启动）是通过 adb shell am start 启动的，那么问题可以重现。

如果应用程序的首次启动是在启动器中单击启动，则该问题不再重现。

android android-activity launchmode
1个回答
0
投票

当您启动 

Activity
时，Android 会查看任务根部是否已存在具有该 
Activity
的任务（它还会比较一些 
Intent
标志，在您的情况下这些标志也会匹配）。如果它找到匹配项，它只是假设您正在尝试将该任务带到前台，并且它会这样做：将现有任务带到前台而不启动 
Activity
 的实例。 这就是为什么当您在后台有一个任务时，当您点击主屏幕上的应用程序图标时，现有任务将被带到前台，而不是 Android 再次启动第一个 
Activity
。这也是当您从“最近任务列表”中选择某项内容时 Android 将另一个任务带到前台的方式。它只是再次启动 root 
Activity
，这会导致 Android 找到现有任务并将其带到前台。

现在通常，当启动器（主屏幕）启动应用程序时，它会在

Intent
中设置一些附加参数：

  • FLAG_ACTIVITY_NEW_TASK
  • FLAG_ACTIVITY_RESET_TASK_IF_NEEDED
  • ACTION_MAIN
  • CATEGORY_LAUNCHER

这样，当您从主屏幕再次启动应用程序时，

Intent
也会设置这些值，以便它们与原始 
Intent
中的值相匹配。由于您使用 ADB 启动活动，因此不会设置这些标志。这与现实场景中发生的情况并不完全匹配，这就是为什么您会看到一些差异。希望这有帮助！

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