Activity lifecycle methods (onCreate, onStart, onResume, onPause, onStop, onDestroy) in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to override the method that is called when the activity is first created.

Android Kotlin

override fun [1](savedInstanceState: Bundle?) {
    super.[1](savedInstanceState)
    setContentView(R.layout.activity_main)
}

Drag options to blanks, or click blank then click option'

AonResume

BonStart

ConCreate

DonPause

Attempts:

3 left

💡 Hint

Common Mistakes

Using onStart instead of onCreate

Forgetting to call super method

The onCreate method is called when the activity is first created. It is where you initialize your UI.

2fill in blank

medium

Complete the code to override the method called when the activity becomes visible to the user.

Android Kotlin

override fun [1]() {
    super.[1]()
    // Activity is now visible
}

Drag options to blanks, or click blank then click option'

AonResume

BonStart

ConPause

DonStop

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing onStart with onResume

Not calling the super method

The onStart method is called when the activity becomes visible to the user but is not yet interactive.

3fill in blank

hard

Fix the error in overriding the method that is called when the activity is about to go into the background.

Android Kotlin

override fun [1]() {
    super.[1]()
    // Pause ongoing actions
}

Drag options to blanks, or click blank then click option'

AonDestroy

BonStop

ConStart

DonPause

Attempts:

3 left

💡 Hint

Common Mistakes

Using onStop instead of onPause

Forgetting to call super method

The onPause method is called when the activity is partially obscured or about to go into the background. It is used to pause ongoing actions.

4fill in blank

hard

Fill both blanks to override methods that handle when the activity is no longer visible and when it is destroyed.

Android Kotlin

override fun [1]() {
    super.[1]()
    // Activity is no longer visible
}

override fun [2]() {
    super.[2]()
    // Cleanup before activity is destroyed
}

Drag options to blanks, or click blank then click option'

AonStop

BonPause

ConDestroy

DonStart

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up onPause and onStop

Not calling super methods

onStop is called when the activity is no longer visible. onDestroy is called before the activity is destroyed and is used for cleanup.

5fill in blank

hard

Fill all three blanks to override methods that manage the activity lifecycle from visible to interactive to paused.

Android Kotlin

override fun [1]() {
    super.[1]()
    // Activity is visible
}

override fun [2]() {
    super.[2]()
    // Activity is interactive
}

override fun [3]() {
    super.[3]()
    // Activity is partially obscured
}

Drag options to blanks, or click blank then click option'

AonStart

BonResume

ConPause

DonStop

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing onPause with onStop

Incorrect order of lifecycle methods

onStart is called when the activity becomes visible, onResume when it becomes interactive, and onPause when it is partially obscured or losing focus.

Practice

1. Which lifecycle method is called first when an Android activity is launched?
onCreate(), onStart(), onResume(), or onPause()?

easy

A. onStart()

B. onResume()

C. onCreate()

D. onPause()

Solution

1. Step 1: Understand activity launch sequence

   When an activity starts, onCreate() is the first method called to set up the UI and initialize components.

2. Step 2: Confirm order of lifecycle methods

   After onCreate(), onStart() and onResume() follow, but they are not first.

3. Final Answer:

   onCreate() -> Option C

4. Quick Check:

   First lifecycle method = onCreate() [OK]

Hint: Remember: onCreate() is always first when activity starts [OK]

Common Mistakes:

• Confusing onStart() as the first method
• Thinking onResume() is called before onCreate()
• Assuming onPause() is called on launch

2. Which of the following is the correct Kotlin syntax to override the onPause() method in an Android activity?

easy

A. override fun onPause() {
pause.super()
}

B. fun onPause() {
super.onPause()
}

C. override onPause() {
super.onPause()
}

D. override fun onPause() {
super.onPause()
}

Solution

1. Step 1: Check Kotlin override syntax

   In Kotlin, to override a method, use override fun methodName() and call super.methodName() inside.

2. Step 2: Validate each option

   override fun onPause() { super.onPause() } correctly uses override fun onPause() and calls super.onPause(). Others miss override keyword, have wrong syntax, or wrong super call.

3. Final Answer:

   override fun onPause() { super.onPause() } -> Option D

4. Quick Check:

   Correct override syntax = override fun onPause() { super.onPause() } [OK]

Hint: Always use 'override fun method()' and call 'super.method()' inside [OK]

Common Mistakes:

• Omitting the override keyword
• Calling super incorrectly
• Wrong function declaration syntax

3. Consider this Kotlin code snippet inside an activity:

override fun onPause() {
    super.onPause()
    println("Paused")
}
override fun onStop() {
    super.onStop()
    println("Stopped")
}

What will be printed if the user presses the home button while the activity is visible?

medium

A. Stopped
Paused

B. Paused
Stopped

C. Paused

D. Stopped

Solution

1. Step 1: Understand lifecycle on home press

   Pressing home triggers onPause() first, then onStop() as activity goes to background.

2. Step 2: Check print order

   Since onPause() runs before onStop(), "Paused" prints first, then "Stopped".

3. Final Answer:

   Paused Stopped -> Option B

4. Quick Check:

   onPause() then onStop() prints = Paused, Stopped [OK]

Hint: onPause() always runs before onStop() when leaving activity [OK]

Common Mistakes:

• Assuming onStop() runs before onPause()
• Thinking only one method runs on home press
• Confusing print order

4. This code snippet is intended to save data when the activity is paused:

override fun onPause() {
    saveData()
}

What is the main problem with this code?

medium

A. Missing call to super.onPause()

B. saveData() should be called in onStop() instead

C. onPause() cannot be overridden

D. saveData() must be asynchronous

Solution

1. Step 1: Check lifecycle method override rules

   When overriding lifecycle methods, always call super.method() to keep system stable.

2. Step 2: Identify missing super call

   The code lacks super.onPause(), which can cause unexpected behavior.

3. Final Answer:

   Missing call to super.onPause() -> Option A

4. Quick Check:

   Always call super in lifecycle overrides [OK]

Hint: Never forget super.onPause() when overriding onPause() [OK]

Common Mistakes:

• Forgetting to call super method
• Thinking onPause() can't be overridden
• Assuming saveData() timing is wrong

5. You want to release a camera resource when the activity is no longer visible to save battery. Which lifecycle method is the best place to release the camera?
A) onDestroy()
B) onStop()
C) onPause()
D) onResume()

hard

A. onPause()

B. onStop()

C. onDestroy()

D. onResume()

Solution

1. Step 1: Understand visibility and resource management

   When activity is partially or fully hidden, onPause() is called first, signaling to release resources like camera to save battery.

2. Step 2: Compare lifecycle methods for releasing resources

   onStop() is later, but releasing in onPause() ensures resources are freed as soon as activity is not in foreground. onDestroy() may never be called if system kills process. onResume() is for acquiring resources.

3. Final Answer:

   onPause() -> Option A

4. Quick Check:

   Release resources in onPause() to save battery [OK]

Hint: Release heavy resources in onPause(), reacquire in onResume() [OK]

Common Mistakes:

• Waiting until onStop() or onDestroy() to release resources
• Releasing resources in onResume() by mistake
• Not releasing resources early enough