android - How Onstop Method work for this demo? -

android - How Onstop Method work for this demo? -

i making demo understand stack , activity life-cycle.

i made:

mainactivity mainactivitydialog (another activity theme dialog) bactivity

i launched app , main activity shown. press button show dialog, mainactivitydialog opened. 1 time again press button on mainactivitydialog bactivity opened. finally, pressed button.

mainactivity -> mainactivitydialog -> bactivity ---back---> mainactivitydialog

here log of app :

my question are:

why mainactivity stopped after launching bactivity mainactivitydialog? after bactivity lifecycle method called, why mainactivitydialog stopped?

after pressing button in bactivity, mainactivity starts first mainactivitydialog starts , mainactivitydialog resume?

the order of calls onstop() , ondestroy() on multiple activities indeterminate.

if have multiple activities in activity stack no longer visible on screen, android may phone call onstop() on them whenever wants , in whatever order wants to. indication activity no longer visible user. cannot rely on order of onstop() calls multiple activities.

the same goes ondestroy(). android may phone call ondestroy() on activity 1 time activity has finished. if have multiple finished activities in task, android may phone call ondestroy() on them whenever wants , in whatever order wants to. indeterminate. phone call ondestroy() inform activity no longer active , should release resources may have.

there no guarantee onstop() or ondestroy() ever called. lastly lifecycle phone call guaranteed onpause(). after that, android can kill process without calling farther lifecycle methods.

in sec question want know why, after user presses button on bactivity, mainactivity starts first followed mainactivitydialog. reason mainactivity visible on screen first , mainactivitydialog visible on screen on top of mainactivity (because mainactivitydialog dialog-themed, doesn't cover entire screen , can see parts of mainactivity underneath it).

android android-activity android-lifecycle