Using "adb logcat" Command to Track the Lifecycle of an Application

Android Tutorials - Herong's Tutorial Examples

∟Using "adb logcat" Command for Debugging

∟Using "adb logcat" Command to Track the Lifecycle of an Application

This section provides a tutorial example how to use the 'adb logcat' command to track the lifecycle of an application. The 'events' log buffer provides log entries for each Activity callback method.

In previous tutorials, we have learned how to use the "adb logcat" command options and arguments filter out log entries and control the output format. Now let's try to use the "adb logcat" to watch how my applications get executed on the device.

1. Run the "adb logcat" command to dump all log entries from "ActivityManager" in the "main" log buffer and leave it there running:

C:\herong>\local\android-sdk-windows\platform-tools\adb logcat -c

C:\herong>\local\android-sdk-windows\platform-tools\adb logcat \
   ActivityManager:V *:S

2. Go to the emulator. Launch my 2 example applications, "AboutAndroid" and "AndroidView".

3. Look at the "adb logcat" window. The following log entries are printed out:

I/ActivityManager(   77): START {act=android.intent.action.MAIN \
   cat=[android.intent.category.LAUNCHER] flg=0x10200000 \
   cmp=com.herongyang/.AboutAndroid} from pid 172
I/ActivityManager(   77): START {act=android.intent.action.MAIN \
   cat=[android.intent.category.HOME] flg=0x10200000 \
   cmp=com.android.launcher/com.android.launcher2.Launcher} from \
   pid 77
I/ActivityManager(   77): START {act=android.intent.action.MAIN \
   cat=[android.intent.category.LAUNCHER] flg=0x10200000 \
   cmp=com.herongyang.view/.AndroidView} from pid 172
I/ActivityManager(   77): Displayed com.herongyang.view/.AndroidView: \
   +1s334ms

4. Run the "adb logcat" command to dump all log entries in the "events" buffer and leave it there running:

C:\herong>\local\android-sdk-windows\platform-tools\adb logcat \
   -b events -c

C:\herong>\local\android-sdk-windows\platform-tools\adb logcat \
   -b events *:V

5. Go to the emulator. Launch my 2 example applications, "AboutAndroid" and "AndroidView". Also click some buttons on "AndroidView".

6. Look at the "adb logcat" window. The following log entries are printed out:

I/am_create_activity(   77): [1095000544,13, \
   com.herongyang/.AboutAndroid,android.intent.action.MAIN,NULL,NULL,\
   270532608]
I/am_pause_activity(   77): [1095117944, \
   com.android.launcher/com.android.launcher2.Launcher]
I/am_on_paused_called(  172): com.android.launcher2.Launcher
I/am_restart_activity(   77): [1095000544,13, \
   com.herongyang/.AboutAndroid]
I/binder_sample(  172): [android.app.IActivityManager,19,82, \
   com.android.launcher,16]
I/am_on_resume_called(  506): com.herongyang.AboutAndroid
I/activity_launch_time(   77): [1095000544, \
   com.herongyang/.AboutAndroid,903,903]
I/am_pause_activity(   77): [1095000544,com.herongyang/.AboutAndroid]
I/am_on_paused_called(  506): com.herongyang.AboutAndroid
I/am_task_to_front(   77): 2
I/am_new_intent(   77): [1095234520,2, \
   com.android.launcher/com.android.launcher2.Launcher, \
   android.intent.action.MAIN,NULL,NULL,274726912]
I/am_resume_activity(   77): [1095117944,2, \
   com.android.launcher/com.android.launcher2.Launcher]
I/am_on_resume_called(  172): com.android.launcher2.Launcher
I/am_create_task(   77): 14
I/am_create_activity(   77): [1095317016,14, \
   com.herongyang.view/.AndroidView,android.intent.action.MAIN,NULL, \
   NULL,270532608]
I/am_pause_activity(   77): [1095117944, \
   com.android.launcher/com.android.launcher2.Launcher]
I/am_on_paused_called(  172): com.android.launcher2.Launcher
I/am_restart_activity(   77): [1095317016,14, \
   com.herongyang.view/.AndroidView]
I/am_on_resume_called(  488): com.herongyang.view.AndroidView
I/activity_launch_time(   77): [1095317016,
   com.herongyang.view/.AndroidView,974,974]
I/binder_sample(  172): [android.app.IActivityManager,19,1189, \
   com.android.launcher,100]
I/am_finish_activity(   77): [1095317016,14, \
   com.herongyang.view/.AndroidView,app-request]
I/am_pause_activity(   77): [1095317016, \
   com.herongyang.view/.AndroidView]
I/am_on_paused_called(  488): com.herongyang.view.AndroidView
I/am_resume_activity(   77): [1095117944,2, \
   com.android.launcher/com.android.launcher2.Launcher]
I/am_on_resume_called(  172): com.android.launcher2.Launcher
I/am_destroy_activity(   77): [1095317016,14, \
   com.herongyang.view/.AndroidView,finish-imm]
I/binder_sample(  488): [android.view.IWindowSession,3,275, \
   com.herongyang.view,55]

Those "am_on_*" log entries from the "events" log buffer record clearly the lifecycle of both applications, com.herongyang.AboutAndroid and com.herongyang.view.AndroidView.