Activity concept in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an Activity in Android?

An Activity is a single screen in an Android app where the user interacts. It controls the UI and handles user actions.

beginner

Which method is called when an Activity is first created?

The onCreate() method is called when the Activity is first created. It is where you set up the UI and initialize components.

intermediate

Name two lifecycle methods called when an Activity becomes visible and when it goes to the background.

onStart() is called when the Activity becomes visible. onStop() is called when the Activity is no longer visible (goes to background).

beginner

How do you start a new Activity from the current Activity?

You create an Intent specifying the new Activity class and call startActivity(intent) to open it.

intermediate

What is the purpose of the onPause() method in an Activity?

onPause() is called when the Activity is partially obscured or about to go into the background. Use it to pause animations or save data.

Which method is NOT part of the Activity lifecycle?

A onClick()

B onStart()

C onCreate()

D onDestroy()

onClick() is an event handler for clicks, not a lifecycle method.

What does the onResume() method indicate?

A Activity is visible and interacting with the user

B Activity is being created

C Activity is stopped

D Activity is destroyed

onResume() means the Activity is visible and ready for user interaction.

How do you open a new Activity named DetailActivity?

A openActivity(DetailActivity)

B startActivity(Intent(this, DetailActivity::class.java))

C launch(DetailActivity)

D new Activity(DetailActivity)

You create an Intent with the current context and target Activity class, then call startActivity.

Which lifecycle method should you use to save user data before the Activity is stopped?

A onCreate()

B onStart()

C onPause()

D onResume()

onPause() is the right place to save data before the Activity goes to background.

What happens when you call finish() inside an Activity?

A Nothing happens

B The Activity restarts

C The Activity pauses

D The Activity closes and is removed from the stack

finish() closes the current Activity and removes it from the back stack.

Explain the Android Activity lifecycle and why it is important.

Think about what happens when the user opens, uses, and leaves an Activity.

Describe how to navigate from one Activity to another in Android.

Consider how you tell Android to show a new screen.