1. Activity Lifecycle
Fall CS2302: Programming Principles

2. Activity States Active (running) Paused Stopped
An active activity is visible on the screen and has the focus. This is the activity the user is interacting with.
Paused
A paused activity is visible on the screen but doesn’t have the focus. A paused activity can be killed when its memory is needed by the OS.
Stopped
A stopped activity is not visible on the screen and is likely to be killed by the system when its memory is needed.
Fall CS2302: Programming Principles

3. Lifecycle Events onCreate() onStart() onResume() onPause() onRestart()
onStop()
onDestroy()
Fall CS2302: Programming Principles

4. Start the first Activity
onCreate
onStart
onResume
Fall CS2302: Programming Principles

5. Start the second Activity from the first Activity
onPause
SecondActivity
onCreate
onStart
onResume
onStop
Fall CS2302: Programming Principles

6. Come back to the first Activity
SecondActivity
onPause
FirstActivity
onRestart
onStart
onResume
onStop
Fall CS2302: Programming Principles

7. Summary
Fall CS2302: Programming Principles