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| -# Flutter Alarm Manager POC |
| 1 | +WIP |
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| - |
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| - |
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| -## Overview |
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| - |
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| -This project demonstrates the implementation of a robust background alarm scheduling system in a Flutter application. It utilizes method channels to communicate with native Android code, Jetpack Compose for the alarm notification UI, and a custom notification service for managing high-priority alarm notifications and display these notification full screen even from app-killed state and lock screen. |
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| - |
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| -### Key Features |
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| - |
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| -- Schedule alarms that run in the background. |
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| -- Display full screen notifications in Lock Screen and handling actions even in app-killed state |
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| -- Handle notification permissions. |
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| -- Use method channels for native code integration. |
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| -- Leverage Jetpack Compose for modern Android UI. |
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| -- Implement a persistent alarm system that works even when the app is closed. |
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| -- Custom notification service for creating and managing high-priority alarm notifications. |
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| - |
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| ---- |
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| - |
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| -## Project Structure |
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| - |
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| -### Flutter (Dart) Side |
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| - |
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| -- `lib/main.dart`: The entry point of the Flutter application. |
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| -- `lib/alarm_manager_screen.dart`: The main screen for scheduling alarms. |
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| -- `lib/alarm_actions_screen.dart`: A screen to view and manage scheduled alarms. |
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| -- `lib/utils/alarm_method_channel.dart`: Dart side of the method channel for communicating with native Android code. |
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| -- `lib/hive/models/alarm_action.dart`: Data Model to store the alarm action selected with its timestamp. |
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| -- `lib/hive/service/database_service.dart`: Contains code related to Hive DB for Crud Operations |
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| - |
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| -### Native Android (Kotlin) Side |
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| - |
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| -- `android/app/src/main/kotlin/.../MainActivity.kt`: Main activity for the Flutter app, handles method channel communication. |
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| -- `android/app/src/main/kotlin/.../AlarmActivity.kt`: Activity for displaying and handling alarms. |
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| -- `android/app/src/main/kotlin/.../AlarmScreen.kt`: Jetpack Compose Screen hosted in AlarmActivity |
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| -- `android/app/src/main/kotlin/.../model/AlarmItem.kt`: Data model for alarm items. |
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| -- `android/app/src/main/kotlin/.../alarmScheduler/AlarmScheduler.kt`: Interface for alarm scheduling. |
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| -- `android/app/src/main/kotlin/.../alarmScheduler/AlarmSchedulerImpl.kt`: Implementation of the alarm scheduling system. |
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| - |
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| -- `android/app/src/main/kotlin/.../AlarmNotificationService.kt`: Interface for the alarm notification service. |
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| -- `android/app/src/main/kotlin/.../AlarmNotificationServiceImpl.kt`: Implementation of the alarm notification service. |
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| - |
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| ---- |
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| - |
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| -## Key Components |
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| - |
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| -### `MainActivity` |
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| - |
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| -Handles Flutter-native method channel communication. This is the entry point for all native-side interactions from Flutter. |
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| - |
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| -### `AlarmActivity` |
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| - |
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| -Displays and handles the alarm UI using Jetpack Compose. This is where the user interacts with the alarm (snooze, accept). |
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| - |
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| -### `AlarmNotificationService` |
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| - |
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| -Responsible for creating and managing high-priority notifications for alarms. It ensures that alarm notifications are persistent, even on the lock screen. |
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| - |
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| -#### Key Responsibilities: |
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| - |
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| -- **Notification Channel Creation**: Creates a high-importance channel for alarms. Sets channel properties to bypass "Do Not Disturb," show on the lock screen, and enable lights and vibration. |
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| -- **Showing Notifications**: Creates a full-screen intent that launches the `AlarmActivity`. Builds a high-priority notification with a full-screen intent. The notification is ongoing and non-cancelable to ensure it persists until user interaction. |
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| - |
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| -```kotlin |
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| - |
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| - val notificationService: AlarmNotificationService = AlarmNotificationServiceImpl(context) |
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| - |
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| - val alarmItem = AlarmItem( |
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| - id = 1, |
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| - message = "Alarm has been ringing" |
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| - ) |
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| -// To display notification |
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| -notificationService.showNotification(AlarmItem(alarmId, message)) |
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| - |
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| -``` |
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| - |
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| -- **Cancelling Notifications**: Cancels a notification by its ID when alarms are dismissed or snoozed. |
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| - |
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| -```kotlin |
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| - |
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| - val notificationService: AlarmNotificationService = AlarmNotificationServiceImpl(context) |
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| - |
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| - val alarmItem = AlarmItem( |
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| - id = 1, |
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| - message = "Alarm has been ringing" |
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| - ) |
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| -// To cancel notification |
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| -notificationService.showNotification(AlarmItem(alarmId, message)) |
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| - |
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| -``` |
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| - |
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| ---- |
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| - |
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| -## Alarm Scheduler |
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| - |
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| -The `AlarmScheduler` interface and its implementation, `AlarmSchedulerImpl`, provide a simple and effective way to schedule and cancel alarms in an Android app. |
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| - |
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| -### Key Responsibilities: |
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| - |
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| -- **Scheduling and Canceling Alarms**: The `AlarmScheduler` is responsible for scheduling alarms to trigger at a specific time. It ensures that the necessary system components, such as `AlarmManager`, are used correctly to wake the device and trigger the alarm on time. |
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| - |
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| -```kotlin |
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| - |
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| - val alarmScheduler = AlarmSchedulerImpl(context) |
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| - val alarmItem = AlarmItem( |
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| - id = 1, |
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| - message = "Alarm has been ringing" |
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| - ) |
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| - // To schedule full screen notification alarms |
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| - alarmScheduler.schedule(alarmItem) |
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| - |
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| -``` |
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| - |
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| -- **Handling Exact Timings**: The scheduler is designed to handle precise alarm timings using Android's `AlarmManager.setExact()` method, which is suitable for alarms requiring exact triggers. |
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| - |
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| -- **Canceling Alarms**: The `AlarmScheduler` also provides functionality to cancel scheduled alarms. It ensures that any pending intents related to the alarm are properly canceled, preventing unnecessary alarms from firing. |
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| - |
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| -```kotlin |
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| - |
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| - val alarmScheduler = AlarmSchedulerImpl(context) |
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| - val alarmItem = AlarmItem( |
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| - id = 1, |
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| - message = "Alarm has been ringing" |
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| - ) |
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| - |
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| - // To cancel alarm |
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| - alarmScheduler.cancel(alarmItem) |
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| - |
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| -``` |
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| - |
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| -- **Managing Alarm Intents**: The `AlarmScheduler` is responsible for creating and managing `PendingIntent` objects that represent the scheduled alarms. These intents are used by the `AlarmManager` to trigger the alarm at the specified time. |
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| - |
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| -## AlarmReceiver |
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| - |
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| -The `AlarmReceiver` is a crucial component in the alarm management system. It extends `BroadcastReceiver`, enabling the app to respond to system-wide broadcast events, specifically alarms that are triggered by the `AlarmManager`. |
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| - |
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| -### Key Responsibilities |
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| - |
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| -**Receiving Broadcasts:** |
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| - |
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| -- The primary role of `AlarmReceiver` is to listen for broadcasts triggered when an alarm goes off, even if the app is in the background or closed. |
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| -- It receives `Intents` with alarm details such as the `ALARM_ID` and the `ALARM_MESSAGE`. |
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| - |
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| -**Handling the Alarm:** |
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| -- Once the alarm is received, it extracts the `ALARM_ID` and `ALARM_MESSAGE` from the `Intent`. If no values are provided, defaults are used (`-1` for `ALARM_ID` and `"Alarm!"` for the message). |
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| -- It then creates an `AlarmItem` object to represent the triggered alarm. |
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| - |
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| -**Displaying Notifications:** |
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| - |
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| -- After receiving the alarm, the receiver creates an instance of `AlarmNotificationService` and invokes its `showNotification` method, which displays a notification to the user about the alarm. |
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| - |
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| -```kotlin |
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| -class AlarmReceiver : BroadcastReceiver() { |
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| - |
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| - |
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| - override fun onReceive(context: Context, intent: Intent?) { |
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| - val alarmId = intent?.getIntExtra("ALARM_ID", -1) ?: -1 |
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| - val message = intent?.getStringExtra("ALARM_MESSAGE") ?: "Alarm!" |
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| - val notificationService: AlarmNotificationService = AlarmNotificationServiceImpl(context) |
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| - notificationService.showNotification(AlarmItem(alarmId, message)) |
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| - } |
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| -} |
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| - |
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| -``` |
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| - |
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| ---- |
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| - |
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| -## Alarm Notification Flow |
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| - |
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| - |
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| -<p style="text-align:center; font-weight:bold;">Flow of Notification Handling</p> |
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| - |
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| -### 1. **Alarm Set from Flutter** |
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| -- The alarm is initially scheduled from the Flutter side using a **Method Channel**. |
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| -- Flutter sends a command to the native Android layer to schedule the alarm using the `AlarmScheduler`. |
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| - |
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| -### 2. **Alarm Trigger and Notification Creation** |
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| -- When the scheduled time arrives, the alarm triggers, and the `AlarmReceiver` captures the broadcast. |
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| -- The receiver then creates an alarm notification via `AlarmNotificationService`, which shows a high-priority, full-screen notification on the device. |
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| -- The notification appears even if the device is locked. |
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| - |
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| -### 3. **User Interaction with the Alarm** |
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| -- When the user interacts with the notification (e.g., accepting or snoozing), the `AlarmActivity` is launched. |
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| -- Inside `AlarmActivity`, the notification content is displayed via a Jetpack Compose `AlarmScreen` interface. |
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| -- The user can either **accept** or **snooze** the alarm, and these actions are captured within the `AlarmActivity`. |
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| - |
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| -### 4. **Handling Accept or Snooze Action** |
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| - |
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| -- Based on the user's action: |
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| - - **Accept**: The `alarmAccepted` method is invoked via the Method Channel, and the alarm is marked as accepted. |
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| - - **Snooze**: The `alarmSnoozed` method is called, which reschedules the alarm for a later time using the `AlarmScheduler`. |
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| -- In both cases, the notification is cancelled after the action is completed. |
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| - |
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| -### 5. **Sending Action Back to Flutter** |
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| -- After the user selects either **accept** or **snooze**, the result of the action is sent back to the Flutter layer through the Method Channel. |
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| -- The Method Channel passes the action result (accept or snooze) back to Flutter, where it can be processed for further logic. |
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| - |
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| -### 6. **Storing the Action in Local Storage (Hive DB)** |
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| - |
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| -- Once the action result is received in Flutter, it is stored locally in the **Hive DB**. |
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| -- Hive is used to store key details like: |
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| - - Whether the alarm was accepted or snoozed. |
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| - - Timestamps of the actions for future reference or history tracking. |
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| -- This ensures that the user's interaction with the alarm is saved persistently, even if the app was closed or in a killed state when the alarm was triggered. |
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| - |
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| -### Key Points: |
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| - |
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| -- **Persistent Storage**: Using Hive for local storage ensures that even in cases where the app was closed, the alarm actions are reliably saved. |
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| -- **Flutter-Android Communication**: The **Method Channel** serves as the bridge for communication between the Flutter and native Android sides, ensuring seamless action handling and data transmission. |
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| -- **State Handling**: The system handles alarms gracefully, whether the app is in a running state or was previously killed, ensuring that alarms work in all scenarios. |
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| - |
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| ---- |
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| - |
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| -## Permissions |
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| - |
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| -### The app requires the following permissions to function correctly: |
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| - |
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| -```xml |
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| - <uses-permission android:name="android.permission.POST_NOTIFICATIONS" /> |
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| - <uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM" /> |
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| - <uses-permission android:name="android.permission.USE_EXACT_ALARM" /> |
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| - <uses-permission android:name="android.permission.WAKE_LOCK" /> |
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| - <uses-permission android:name="android.permission.USE_FULL_SCREEN_INTENT" /> |
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| -``` |
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| - |
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| -### Also add the following in the Notification Activity in your Manifest |
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| - |
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| -```xml |
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| - <activity |
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| - android:name=".activity.AlarmActivity" |
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| - android:showWhenLocked="true" |
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| - android:turnScreenOn="true" |
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| - android:exported="false" /> |
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| - |
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| -``` |
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| - |
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| -# Contributing |
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| - |
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| -### Contributions are welcome! Please feel free to submit a Pull Request. |
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| - |
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| ----- |
| 3 | +Forked from https://github.com/Applinx-Tech/Flutter-Alarm-Manager-POC. |
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