Location services in Android Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

What is the output of this code when location permission is denied?

Consider this Kotlin snippet for requesting location permission in an Android app. What will the app display if the user denies the location permission?

Android Kotlin

val requestPermissionLauncher = registerForActivityResult(ActivityResultContracts.RequestPermission()) { isGranted: Boolean ->
  if (isGranted) {
    textView.text = "Permission granted"
  } else {
    textView.text = "Permission denied"
  }
}

requestPermissionLauncher.launch(Manifest.permission.ACCESS_FINE_LOCATION)

A The TextView shows "Permission denied"

B The TextView shows "Permission granted"

C The app crashes with SecurityException

D The TextView remains empty

💡 Hint

Think about what happens when the permission callback receives false.

If the user denies the permission, the callback receives false, so the TextView text is set to "Permission denied".

🧠 Conceptual

intermediate

Which location provider gives the most accurate location?

Android offers different location providers. Which one typically provides the most accurate location data?

A GPS provider (uses satellites)

B Network provider (uses Wi-Fi and cell towers)

C Passive provider (listens to other apps' location requests)

D Bluetooth provider

💡 Hint

Think about which source uses satellites directly.

The GPS provider uses satellites and usually gives the most accurate location outdoors.

❓ lifecycle

advanced

What happens if you start location updates in onCreate and never stop them?

In an Android app, if you start location updates in the onCreate method of an Activity and never stop them, what is the likely result?

A Location updates only run while Activity is visible

B Location updates stop automatically when Activity is paused

C App crashes with IllegalStateException

D Location updates continue, causing battery drain even when app is in background

💡 Hint

Consider what happens if you don't remove location updates explicitly.

Without stopping location updates, they continue running, draining battery even if the app is not visible.

❓ navigation

advanced

How to navigate to app settings to enable location permission?

Which Intent action correctly opens the app's settings page so the user can enable location permission manually?

A Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION)

B Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS).apply { data = Uri.fromParts("package", packageName, null) }

C Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS)

D Intent(Settings.ACTION_WIFI_SETTINGS)

💡 Hint

Think about how to open the specific app's settings page.

Using ACTION_APPLICATION_DETAILS_SETTINGS with the app package Uri opens the app's settings page.

🔧 Debug

expert

Why does this location request code cause a crash?

Examine this Kotlin code snippet. Why does it cause a crash when run?

Android Kotlin

val fusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
fusedLocationClient.lastLocation.addOnSuccessListener { location ->
  if (location != null) {
    textView.text = "Lat: ${location.latitude}, Lon: ${location.longitude}"
  } else {
    textView.text = "Location not available"
  }
}

A It crashes because addOnSuccessListener is not a valid method

B It crashes because fusedLocationClient is not initialized properly

C It crashes because location can be null and code does not check for null

D It crashes because textView is not declared

💡 Hint

Think about what happens if the location is not available yet.

The lastLocation can be null if no location is cached yet. Accessing latitude without null check causes NullPointerException.