Notifications (local) in Flutter - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the Flutter local notifications plugin.

Flutter

final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await flutterLocalNotificationsPlugin.[1]();
  runApp(MyApp());
}

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

Ainitialize

Bstart

Csetup

Dlaunch

Attempts:

3 left

💡 Hint

Common Mistakes

Using start() or setup() which do not exist.

Forgetting to call initialize before using notifications.

The method to initialize the plugin is called initialize().

2fill in blank

medium

Complete the code to show a simple notification with a title and body.

Flutter

await flutterLocalNotificationsPlugin.show(
  0,
  'Hello',
  'This is a notification',
  [1]
);

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

ANotificationSettings()

BNotificationConfig()

CNotificationDetails(android: AndroidNotificationDetails('channelId', 'channelName', importance: Importance.defaultImportance))

DNotificationOptions()

Attempts:

3 left

💡 Hint

Common Mistakes

Passing NotificationSettings or other incorrect classes.

Not providing NotificationDetails causes errors.

The show method requires NotificationDetails to specify platform-specific settings.

3fill in blank

hard

Fix the error in the AndroidNotificationDetails constructor by completing the missing required parameter.

Flutter

const AndroidNotificationDetails(
  'channelId',
  'channelName',
  [1]
)

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

Asound: RawResourceAndroidNotificationSound('sound')

Bpriority: Priority.high

Cicon: 'app_icon'

Dimportance: Importance.max

Attempts:

3 left

💡 Hint

Common Mistakes

Using priority instead of importance in AndroidNotificationDetails.

Omitting importance causes runtime errors.

The importance parameter is required to set the notification importance level.

4fill in blank

hard

Fill both blanks to create a notification channel with high importance and enable vibration.

Flutter

const AndroidNotificationDetails(
  'channelId',
  'channelName',
  importance: [1],
  vibrationPattern: [2]
)

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

AImportance.high

B[0, 1000, 500, 2000]

CImportance.low

D[100, 200, 300]

Attempts:

3 left

💡 Hint

Common Mistakes

Using Importance.low for high priority notifications.

Providing incorrect vibration pattern format.

Use Importance.high for strong notification and a vibration pattern array for vibration.

5fill in blank

hard

Fill all three blanks to schedule a notification 5 seconds from now with a specific channel and title.

Flutter

await flutterLocalNotificationsPlugin.zonedSchedule(
  1,
  [1],
  'Scheduled Notification',
  tz.TZDateTime.now(tz.local).add(const Duration(seconds: [2])),
  NotificationDetails(
    android: AndroidNotificationDetails(
      [3],
      'Scheduled Channel',
      importance: Importance.high
    )
  ),
  androidAllowWhileIdle: true,
  uiLocalNotificationDateInterpretation: UILocalNotificationDateInterpretation.absoluteTime
);

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

A'Reminder'

B5

C'scheduled_channel_id'

D'Alert'

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong channel id string.

Setting wrong delay duration.

Confusing title with channel name.

The title is 'Reminder', the delay is 5 seconds, and the channel id is 'scheduled_channel_id'.

Practice

1. What is the main purpose of local notifications in a Flutter app?

easy

A. To alert users even when the app is closed or in the background

B. To send messages to a server

C. To update the app's UI instantly

D. To change app theme colors automatically

Solution

1. Step 1: Understand local notifications

   Local notifications are alerts shown to users even if the app is not open or running in the background.

2. Step 2: Compare options

   Options B, C, and D describe other app features unrelated to local notifications.

3. Final Answer:

   To alert users even when the app is closed or in the background -> Option A

4. Quick Check:

   Local notifications alert users outside app use = A [OK]

Hint: Local notifications work when app is not active [OK]

Common Mistakes:

• Confusing local notifications with server messages
• Thinking notifications only work when app is open
• Mixing UI updates with notification purpose

2. Which Flutter plugin is commonly used to show local notifications?

easy

A. firebase_messaging

B. flutter_local_notifications

C. provider

D. http

Solution

1. Step 1: Identify notification plugins

   The plugin flutter_local_notifications is designed for local notifications in Flutter apps.

2. Step 2: Eliminate unrelated plugins

   http is for network calls, provider for state management, firebase_messaging for push notifications, not local.

3. Final Answer:

   flutter_local_notifications -> Option B

4. Quick Check:

   Local notifications plugin = flutter_local_notifications [OK]

Hint: Local notifications use flutter_local_notifications plugin [OK]

Common Mistakes:

• Choosing firebase_messaging which is for push, not local
• Confusing state management plugins with notification plugins
• Selecting network plugins by mistake

3. What will happen if you call show() on a local notification without initializing the plugin first?

medium

A. The notification will show normally

B. The notification will show only on Android devices

C. The notification will be delayed by 5 seconds

D. The app will crash or throw an error

Solution

1. Step 1: Understand plugin initialization

   Local notification plugins require initialization before use to set up channels and permissions.

2. Step 2: Consequence of missing initialization

   Calling show() without initialization causes runtime errors or crashes because the plugin is not ready.

3. Final Answer:

   The app will crash or throw an error -> Option D

4. Quick Check:

   Uninitialized plugin causes error/crash = B [OK]

Hint: Always initialize plugin before showing notifications [OK]

Common Mistakes:

• Assuming notifications show without initialization
• Thinking notifications delay automatically
• Believing platform-specific behavior without init

4. Given this code snippet, what is the error?

final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  // Missing initialization here
  await flutterLocalNotificationsPlugin.show(
    0,
    'Hello',
    'Welcome to Flutter',
    NotificationDetails(
      android: AndroidNotificationDetails('channelId', 'channelName')
    )
  );
}

medium

A. WidgetsFlutterBinding.ensureInitialized() is unnecessary

B. NotificationDetails is not imported

C. Missing call to initialize() before show()

D. Notification ID cannot be zero

Solution

1. Step 1: Check plugin initialization

   The code calls show() without calling initialize() on flutterLocalNotificationsPlugin first.

2. Step 2: Understand consequences

   Without initialize(), the plugin is not ready, causing errors when showing notifications.

3. Final Answer:

   Missing call to initialize() before show() -> Option C

4. Quick Check:

   Initialize plugin before show() = C [OK]

Hint: Always initialize plugin before calling show() [OK]

Common Mistakes:

• Ignoring the need to initialize plugin
• Thinking zero ID is invalid
• Assuming ensureInitialized() replaces plugin init

5. You want to create a local notification channel with high importance and priority on Android. Which code snippet correctly sets this up?

hard

A. AndroidNotificationDetails('channelId', 'channelName', importance: Importance.high, priority: Priority.high)

B. AndroidNotificationDetails('channelId', 'channelName', importance: Importance.low, priority: Priority.min)

C. AndroidNotificationDetails('channelId', 'channelName', importance: Importance.defaultImportance, priority: Priority.defaultPriority)

D. AndroidNotificationDetails('channelId', 'channelName')

Solution

1. Step 1: Understand importance and priority

   High importance and priority make notifications more visible and urgent on Android.

2. Step 2: Check code options

   AndroidNotificationDetails('channelId', 'channelName', importance: Importance.high, priority: Priority.high) sets importance and priority to high, matching the requirement. Others set low, default, or omit these settings.

3. Final Answer:

   AndroidNotificationDetails('channelId', 'channelName', importance: Importance.high, priority: Priority.high) -> Option A

4. Quick Check:

   High importance and priority = AndroidNotificationDetails('channelId', 'channelName', importance: Importance.high, priority: Priority.high) [OK]

Hint: Use Importance.high and Priority.high for urgent notifications [OK]

Common Mistakes:

• Leaving importance and priority at default
• Using low importance for urgent alerts
• Omitting priority setting