Deep links in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an intent filter for a deep link in AndroidManifest.xml.

Android Kotlin

<intent-filter>
    <action android:name="[1]" />
    <category android:name="android.intent.category.DEFAULT" />
    <category android:name="android.intent.category.BROWSABLE" />
</intent-filter>

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

Aandroid.intent.action.CALL

Bandroid.intent.action.MAIN

Candroid.intent.action.SEND

Dandroid.intent.action.VIEW

Attempts:

3 left

💡 Hint

Common Mistakes

Using MAIN action instead of VIEW.

Forgetting to include BROWSABLE category.

The action android.intent.action.VIEW is used to handle deep links in Android.

2fill in blank

medium

Complete the code to specify the scheme for a deep link in the intent filter.

Android Kotlin

<data android:scheme="[1]" />

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

Aftp

Bhttp

Cfile

Dmailto

Attempts:

3 left

💡 Hint

Common Mistakes

Using ftp or mailto which are not common for app deep links.

Confusing file scheme with web URLs.

The http scheme is commonly used for web deep links.

3fill in blank

hard

Fix the error in the Kotlin code to handle the deep link intent in an Activity.

Android Kotlin

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    val intent = [1]
    val data = intent?.data
    if (data != null) {
        // Handle the deep link
    }
}

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

Aintent

BgetIntent()

CgetIntent

DgetIntentData()

Attempts:

3 left

💡 Hint

Common Mistakes

Using getIntent() which is Java syntax.

Using a non-existent method getIntentData().

In Kotlin, the current intent is accessed via the intent property, not getIntent().

4fill in blank

hard

Fill both blanks to declare a deep link intent filter with host and path prefix.

Android Kotlin

<intent-filter>
    <action android:name="android.intent.action.VIEW" />
    <category android:name="android.intent.category.DEFAULT" />
    <category android:name="android.intent.category.BROWSABLE" />
    <data android:scheme="https" android:host="[1]" android:pathPrefix="[2]" />
</intent-filter>

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

Awww.example.com

B/products

Cexample.com

D/home

Attempts:

3 left

💡 Hint

Common Mistakes

Using www in host which can cause mismatch.

Using incorrect path prefix without leading slash.

The host should be the domain without www for consistency, and pathPrefix defines the starting path segment.

5fill in blank

hard

Fill all three blanks to create a Kotlin function that extracts a query parameter named 'id' from a deep link Uri.

Android Kotlin

fun getIdFromDeepLink(intent: Intent): String? {
    val data = intent.data
    return data?.[1]("[2]") ?: [3]
}

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

AgetQueryParameter

Bid

Cnull

DgetQuery

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-existent method like getQuery.

Returning an empty string instead of null.

The Uri method getQueryParameter retrieves the value of a query parameter by name. If the parameter is missing, returning null is appropriate.

Practice

1. What is the main purpose of a deep link in an Android app?

easy

A. To open a specific screen inside the app from an external URL

B. To update the app's user interface colors

C. To increase the app's memory usage

D. To change the app's icon on the home screen

Solution

1. Step 1: Understand deep link functionality

   Deep links allow an app to open a specific screen or content when a user clicks a URL outside the app.

2. Step 2: Compare options with this purpose

   Only To open a specific screen inside the app from an external URL describes opening a specific screen from an external URL, which matches deep link behavior.

3. Final Answer:

   To open a specific screen inside the app from an external URL -> Option A

4. Quick Check:

   Deep link purpose = open specific screen [OK]

Hint: Deep links open app screens from outside links [OK]

Common Mistakes:

• Confusing deep links with UI styling
• Thinking deep links change app icons
• Assuming deep links increase memory

2. Which XML element is used to declare a deep link in AndroidManifest.xml?

easy

A. <provider>

B.

C. <service>

D. <activity>

Solution

1. Step 1: Identify where deep links are declared

   Deep links are declared inside an element within an activity in AndroidManifest.xml.

2. Step 2: Match options to this element

   Only is used to specify deep link URL patterns and actions.

3. Final Answer:

   <intent-filter> -> Option B

4. Quick Check:

   Deep links declared in intent-filter [OK]

Hint: Deep links go inside intent-filter tags [OK]

Common Mistakes:

• Confusing activity tag with deep link declaration
• Using service or provider tags incorrectly
• Not nesting intent-filter inside activity

3. Given this intent filter snippet in AndroidManifest.xml, what URL will open the app's activity?

<intent-filter>
  <action android:name="android.intent.action.VIEW" />
  <category android:name="android.intent.category.DEFAULT" />
  <category android:name="android.intent.category.BROWSABLE" />
  <data android:scheme="https" android:host="example.com" android:pathPrefix="/profile" />
</intent-filter>

medium

A. https://example.com/about

B. http://example.com/profile

C. https://example.com/profile/settings

D. https://example.org/profile

Solution

1. Step 1: Analyze the intent filter data attributes

   The scheme is https, host is example.com, and pathPrefix is /profile, so URLs starting with https://example.com/profile will match.

2. Step 2: Check each option against these rules

   https://example.com/profile/settings matches https scheme, example.com host, and path starting with /profile. Options B (http scheme), C (wrong path), and D (wrong host) do not match.

3. Final Answer:

   https://example.com/profile/settings -> Option C

4. Quick Check:

   Match scheme, host, pathPrefix = https://example.com/profile/settings [OK]

Hint: Match scheme, host, and pathPrefix exactly [OK]

Common Mistakes:

• Ignoring scheme (http vs https)
• Confusing host names
• Not checking pathPrefix carefully

4. What is wrong with this intent filter for a deep link?

<intent-filter>
  <action android:name="android.intent.action.VIEW" />
  <category android:name="android.intent.category.LAUNCHER" />
  <data android:scheme="myapp" />
</intent-filter>

medium

A. It uses LAUNCHER category instead of BROWSABLE

B. It is missing the action VIEW

C. The scheme attribute is invalid

D. It should be inside a service tag

Solution

1. Step 1: Check required categories for deep links

   Deep links require the BROWSABLE category to allow opening from browsers or external apps.

2. Step 2: Identify incorrect category usage

   This intent filter uses LAUNCHER category, which is for app launchers, not deep links.

3. Final Answer:

   It uses LAUNCHER category instead of BROWSABLE -> Option A

4. Quick Check:

   Deep links need BROWSABLE category [OK]

Hint: Deep links need BROWSABLE, not LAUNCHER category [OK]

Common Mistakes:

• Using LAUNCHER category for deep links
• Forgetting to add BROWSABLE category
• Placing intent-filter inside wrong tag

5. You want your app to open a user profile screen when a link like myapp://user/123 is clicked. Which intent filter correctly handles this deep link?

hard

A. \n \n \n \n

B. \n \n \n \n \n

C. \n \n \n \n

D. \n \n \n \n \n

Solution

1. Step 1: Check required action and categories for deep links

   Deep links need action VIEW and categories DEFAULT and BROWSABLE to work properly.

2. Step 2: Verify data attributes match the URL pattern

   The URL myapp://user/123 has scheme="myapp", host="user", path="/123". Needs matching scheme, host, and pathPattern="/.*" for variable IDs.

3. Step 3: Compare options

   The filter with scheme="myapp", host="user", pathPattern="/.*", VIEW action, DEFAULT and BROWSABLE matches perfectly. pathPrefix="/user" without host mismatches path="/123". Missing BROWSABLE limits external opening. MAIN/LAUNCHER is incorrect for deep links.

4. Final Answer:

   Intent filter with VIEW action, DEFAULT/BROWSABLE categories, scheme myapp, host user, pathPattern /.* -> Option D

5. Quick Check:

   scheme=myapp host=user pathPattern=/.* VIEW BROWSABLE [OK]

Hint: VIEW action, DEFAULT/BROWSABLE categories, scheme+host+pathPattern [OK]

Common Mistakes:

• Missing BROWSABLE category
• Using MAIN action instead of VIEW
• Confusing pathPrefix with host+pathPattern
• Wrong categories for deep links