SavedStateHandle in Android Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

SavedStateHandle preserves UI state on configuration change

Consider a ViewModel using SavedStateHandle to store a counter value. What will be the value of counter after a device rotation if the user incremented it to 5 before rotation?

Android Kotlin

class CounterViewModel(private val state: SavedStateHandle) : ViewModel() {
  var counter: Int
    get() = state.get<Int>("counter") ?: 0
    set(value) = state.set("counter", value)
}

// User increments counter to 5, then rotates device.

A counter will increment automatically to 6 after rotation

B counter will remain 5 after rotation

C counter will be null after rotation causing crash

D counter will reset to 0 after rotation

💡 Hint

SavedStateHandle keeps data across configuration changes like rotation.

SavedStateHandle stores data in a bundle that survives configuration changes, so the counter value 5 is preserved after rotation.

❓ lifecycle

intermediate

When is SavedStateHandle data cleared?

At what point is the data stored in SavedStateHandle cleared automatically by the Android system?

A When the ViewModel is cleared after the associated UI is destroyed permanently

B When the app process is killed by the system

C When the device is rotated

D When the user presses the back button once

💡 Hint

Think about the lifecycle of ViewModel and when it is destroyed.

SavedStateHandle data is cleared when the ViewModel is cleared, which happens when the UI is permanently destroyed, not on rotation or temporary events.

📝 Syntax

advanced

Correct way to retrieve a nullable value from SavedStateHandle

Which option correctly retrieves a nullable String value named "username" from SavedStateHandle in Kotlin?

Android Kotlin

val username: String? = savedStateHandle.???

A getOrDefault("username", "")

B getValue("username")

C get<String>("username")

D getNullable("username")

💡 Hint

Check the official SavedStateHandle API for retrieving values.

The method get(key) returns a nullable value of type T or null if not present. Other methods do not exist or have different signatures.

🔧 Debug

advanced

Why does this SavedStateHandle update not persist after process death?

Given this code snippet, why does the updated value not persist after the app process is killed and restarted?

savedStateHandle["score"] = 10
// app is killed and restarted
val score = savedStateHandle.get("score") ?: 0

A The value 10 is not serializable and cannot be saved

B The ViewModel was not recreated properly after restart

C The key "score" is invalid and cannot be saved

D SavedStateHandle only saves data during configuration changes, not process death

💡 Hint

Think about what SavedStateHandle is designed to save and what it is not.

SavedStateHandle saves data to survive configuration changes but does not persist data across process death. For that, you need persistent storage.

🧠 Conceptual

expert

How does SavedStateHandle integrate with Jetpack Navigation component?

Which statement best describes how SavedStateHandle works with Jetpack Navigation to pass and save UI state between destinations?

A SavedStateHandle automatically saves and restores navigation arguments and state when navigating between destinations

B SavedStateHandle requires manual serialization of navigation arguments to bundles before navigation

C SavedStateHandle cannot be used with Jetpack Navigation and is only for ViewModel internal state

D SavedStateHandle only works with fragments, not with navigation components

💡 Hint

Consider how navigation arguments and SavedStateHandle share data.

Jetpack Navigation integrates with SavedStateHandle to automatically save and restore navigation arguments and UI state across configuration changes and process death (if saved in saved state registry).