Android Activity Lifecycle

gistfile1.txt

[...] = starting state

States:
    not running (dead)
    onResume    (running)
    onStop      (minimized)
    onPause     (screen off)

Launch Application:

    [not running|onStop] (onCreate|onRestart) -> onStart -> onResume

Press Home:

    [onResume]    onPause -> onStop

Press Back:
    If back stack is empty:
        [onResume]    onPause -> onStop -> onDestroy
    If back stack is not empty:
        [B.onResume]  B.onPause                                           -> B.onStop -> B.onDestroy
                                -> A.onRestart -> A.onStart -> A.onResume
    If back stack is not empty and previous activity was cleared for memory:
        [B.onResume]  B.onPause -> B.onStop -> B.onDestroy
                                                           -> A.onCreate -> A.onStart -> A.onResume

Turn Off Screen:

    [onResume]    onPause

Turn On Screen:

    [onPause]     onResume

Calling startActivity:

                             -> B.onCreate -> B.onStart -> B.onResume
    [A.onResume]  A.onPause                                           -> A.onStop
    
Rotating

    [onResume]    onPause -> onStop -> onDestroy -> onCreate -> onStart -> onResume

Freeing more memory:

    [onPause]     not running
    [onStop]      not running
    [onDestroy]   not running

Edge Cases:

onStart -> onStop

    Open activity (onStart -> onResume) and open a dialog above it (onPause).
    Press home (onStop) and reopen (onStart).
    Press home (onStop)

No Activities in back stack

    Pressing back to an activity that was cleared due to memory constraints
    Reorienting root activity