Why navigation manages app flow in Android Kotlin - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to navigate from one screen to another using Navigation Component.

Android Kotlin

findNavController().navigate([1])

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

AR.id.action_home_to_detail

BstartActivity(Intent(this, DetailActivity::class.java))

CsetContentView(R.layout.detail)

Dfinish()

Attempts:

3 left

💡 Hint

Common Mistakes

Using startActivity instead of Navigation Component navigation.

Passing layout resource instead of action ID.

Calling finish() which closes the current screen.

Using Navigation Component, you navigate by calling findNavController().navigate() with the action ID defined in navigation graph.

2fill in blank

medium

Complete the code to define a navigation action in the navigation graph XML.

Android Kotlin

<action android:id="@+id/[1]" app:destination="@id/detailFragment" />

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Ago_detail

Bopen_detail

Cnavigate_to_detail

Daction_home_to_detail

Attempts:

3 left

💡 Hint

Common Mistakes

Using arbitrary names that don't match code references.

Missing the 'action_' prefix.

The action ID must match the one used in code for navigation. It usually follows the pattern action_source_to_destination.

3fill in blank

hard

Fix the error in the code to correctly navigate with arguments.

Android Kotlin

val action = HomeFragmentDirections.[1](userId)
findNavController().navigate(action)

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

AactionHomeToDetail

BnavigateToDetail

CgoToDetail

DopenDetail

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect method names that don't exist in directions class.

Not passing required arguments.

When using Safe Args, the generated directions class uses camelCase action names matching the navigation graph action ID.

4fill in blank

hard

Fill both blanks to check if the current destination is the home screen before navigating.

Android Kotlin

if (findNavController().currentDestination?.id == [1]) {
  findNavController().navigate([2])
}

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AR.id.homeFragment

BR.id.action_home_to_detail

CR.id.detailFragment

DR.id.action_detail_to_home

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing with action IDs instead of fragment IDs.

Using wrong action IDs for navigation.

Check if the current screen is homeFragment by comparing IDs, then navigate using the correct action ID.

5fill in blank

hard

Fill all three blanks to create a navigation graph XML snippet with a start destination and two fragments.

Android Kotlin

<navigation xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  app:startDestination="@id/[1]">
  <fragment android:id="@+id/[2]" android:name="com.example.HomeFragment" />
  <fragment android:id="@+id/[3]" android:name="com.example.DetailFragment" />
</navigation>

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AhomeFragment

CdetailFragment

DmainFragment

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same ID for both fragments.

Setting startDestination to a non-existent fragment.

The start destination is the homeFragment. The two fragments must have unique IDs matching their names.