Android LifeCycle - When Home and Back is Pressed

Question

I have a quiz application project for our school. I want to prevent the users not to press the home and back button or leave the app, because if they do they will get 0 score.

We know about the lifecycle...

Start Application > onCreate > OnStart > OnResume > Activity Is running > OnFreeze > OnPause

If i pressed the home and back button, what method in the lifecycle will be invoked if I start the application again?

And in that method I will make a code to say the user has committed/cheat/left the application. Im thinking in the onResume?

Thanks.

Answer 1

When back button pressed and exit the app

onPaused() -> onStop() -> onDestory()

When home button pressed

onPaused() -> onStop()

After pressed home button when again open app from recent task list or clicked on icon

onRestart() -> onStart() -> onResume()

Back button pressed from another app or settings then user can see our app

onRestart() -> onStart() -> onResume()

When open another app from notification bar or open settings

onPaused() -> onStop()

Answer 2

Activity base class contains events that govern the life cycle of an activity.

onCreate(): Called when the activity is first created

onStart(): Called when the activity becomes visible to the user

onResume(): Called when the activity starts interacting with the user

onPause(): Called when the current activity is being paused and the previous activity is being resumed

onStop(): Called when the activity is no longer visible to the user

onDestroy(): Called before the activity is destroyed by the system

onRestart(): Called when the activity has been stopped and is restarting again

Example

public class LifeCycleActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main); 
    Toast.makeText(LifeCycleActivity.this,"ON CREATE", Toast.LENGTH_SHORT).show(); 
} 
@Override
protected void onStart() {
   // TODO Auto-generated method stub
   super.onStart(); 
    Toast.makeText(LifeCycleActivity.this,"ON START", Toast.LENGTH_SHORT).show();
} 
@Override
protected void onResume() {
   // TODO Auto-generated method stub
   super.onResume(); 
    Toast.makeText(LifeCycleActivity.this,"ON RESUME", Toast.LENGTH_SHORT).show(); 
} 
@Override
protected void onPause() {
   // TODO Auto-generated method stub
   super.onPause(); 
    Toast.makeText(LifeCycleActivity.this,"ON PAUSE", Toast.LENGTH_SHORT).show(); 
} 
@Override
protected void onRestart() {
   // TODO Auto-generated method stub
   super.onRestart(); 
    Toast.makeText(LifeCycleActivity.this,"ON RESTART", Toast.LENGTH_SHORT).show(); 
} 
@Override
protected void onStop() {
   // TODO Auto-generated method stub
   super.onStop(); 
    Toast.makeText(LifeCycleActivity.this,"ON STOP", Toast.LENGTH_SHORT).show(); 
} 
@Override
protected void onDestroy() {
   // TODO Auto-generated method stub
   super.onDestroy(); 
    Toast.makeText(LifeCycleActivity.this,"ON DESTROY", Toast.LENGTH_SHORT).show();
} 
}  

Figure

For more details visit here

and Managing the Activity Lifecycle

Answer 3

You can find everything from here.