Programmatically close recent apps

It seems and is the most obvious choice to close apps running in background in order to give a device a small boost. Android’s recents screen is designed to allow users to quickly stop apps from running with a simple swipe gesture. But there has to be a way this can be achieved with a script? Given diversity of a designs for recents screen across multitude of manufactures, it would be almost impossible to come up with a solution to automate that gesture, instead there is more basic solution.

1. Close any package

First step is fining a way of closing/killing an app via ADB:

am force-stop: force stop everything associated with <PACKAGE>.
 --user <USER_ID> | all | current: Specify user to force stop;
 all users if not specified.

As it turns out, its rather simple – activity manager to the rescue. The only required parameter is the package name (e.g com.xanh.draftnotes).

2. Get the list of running apps

Now, we need to get a list of recently opened apps, which after a little bit of digging, turns out not to be as difficult:

$ adb shell dumpsys window a
  WINDOW MANAGER ANIMATOR STATE (dumpsys window animator)
  DisplayContentsAnimator #0:
  Window #0: WindowStateAnimator{28c00a1 com.android.systemui.ImageWallpaper}
  Window #1: WindowStateAnimator{dd8ddb0 com.xanh.draftnotes.debug/com.xanh.draftnotes.MainActivity}
  Window #2: WindowStateAnimator{d744504 com.google.android.youtube/com.google.android.apps.youtube.app.WatchWhileActivity}
  Window #3: WindowStateAnimator{ca0caed com.google.android.apps.plus/com.google.android.apps.plus.phone.BinderHomeActivity}
  Window #4: WindowStateAnimator{b5382c6 com.android.systemui/com.android.systemui.recents.RecentsActivity}
  Window #5: WindowStateAnimator{ab7acf3 com.google.android.googlequicksearchbox/com.google.android.launcher.GEL}
  Window #6: WindowStateAnimator{f023429 InputMethod}
  Window #7: WindowStateAnimator{7c705dd AssistPreviewPanel}
  Window #8: WindowStateAnimator{9750552 KeyguardScrim}
  Window #9: WindowStateAnimator{dde7023 StatusBar}
  Window #10: WindowStateAnimator{bf29920 NavigationBar}
  no ScreenRotationAnimation

mAnimTransactionSequence=19515 mForceHiding=KEYGUARD_NOT_SHOWN
 mCurrentTime=360543020 (1553036 ms ago)
 mBulkUpdateParams=0x8 ORIENTATION_CHANGE_COMPLETE

This might not look like a final solution, however Window manager actually contains a list of currently opened apps (with some additions, that can be easily filtered). Let’s apply some grep to make it more usable.

$ adb shell dumpsys window a | grep "/" | cut -d "{" -f2 | cut -d "/" -f1 | cut -d " " -f2

This should result in following list:

com.xanh.draftnotes.debug
com.google.android.youtube
com.google.android.apps.plus
com.android.systemui
com.google.android.googlequicksearchbox

The last step is to filter com.android.systemui & com.google.android.googlequicksearchbox packages and looping remaining packages through am force-stop <package>.