fix(ios): pass inputData to periodic background tasks

- Store inputData in UserDefaults when registering periodic tasks
- Retrieve and pass stored inputData when executing periodic tasks
- Fix issue where periodic tasks received nil inputData instead of provided data
- Update documentation with periodic task inputData examples

Closes #612

Author: ened

docs/quickstart.mdx

@@ -176,6 +176,19 @@ Workmanager().registerPeriodicTask(
   "cleanup",
   frequency: Duration(hours: 24),
 );
+
+// Schedule a periodic task with input data
+Workmanager().registerPeriodicTask(
+  "sync-task",
+  "data_sync",
+  frequency: Duration(hours: 6),
+  inputData: <String, dynamic>{
+    'server_url': 'https://api.example.com',
+    'sync_type': 'full',
+    'max_retries': 3,
+  },
+);
+```
 ```
 
 ## Task Results
@@ -200,4 +213,4 @@ Your background tasks can return:
 
 - **[Task Customization](customization)** - Advanced configuration with constraints, input data, and management
 - **[Debugging Guide](debugging)** - Learn how to debug and troubleshoot background tasks  
-- **[Example App](https://github.com/fluttercommunity/flutter_workmanager/tree/main/example)** - Complete working demo
+- **[Example App](https://github.com/fluttercommunity/flutter_workmanager/tree/main/example)** - Complete working demo

workmanager_apple/ios/Sources/workmanager_apple/UserDefaultsHelper.swift

@@ -15,9 +15,15 @@ struct UserDefaultsHelper {
 
     enum Key {
         case callbackHandle
+        case periodicTaskInputData(taskIdentifier: String)
 
         var stringValue: String {
-            return "\(WorkmanagerPlugin.identifier).\(self)"
+            switch self {
+            case .callbackHandle:
+                return "\(WorkmanagerPlugin.identifier).callbackHandle"
+            case .periodicTaskInputData(let taskIdentifier):
+                return "\(WorkmanagerPlugin.identifier).periodicTaskInputData.\(taskIdentifier)"
+            }
         }
     }
 
@@ -31,6 +37,16 @@ struct UserDefaultsHelper {
         return getValue(for: .callbackHandle)
     }
 
+    // MARK: periodicTaskInputData
+
+    static func storePeriodicTaskInputData(_ inputData: [String: Any]?, forTaskIdentifier taskIdentifier: String) {
+        store(inputData, key: .periodicTaskInputData(taskIdentifier: taskIdentifier))
+    }
+
+    static func getStoredPeriodicTaskInputData(forTaskIdentifier taskIdentifier: String) -> [String: Any]? {
+        return getValue(for: .periodicTaskInputData(taskIdentifier: taskIdentifier))
+    }
+
     // MARK: Private helper functions
 
     private static func store<T>(_ value: T, key: Key) {

workmanager_apple/ios/Sources/workmanager_apple/WorkmanagerPlugin.swift

@@ -44,10 +44,13 @@ public class WorkmanagerPlugin: FlutterPluginAppLifeCycleDelegate, FlutterPlugin
         // If frequency is not provided it will default to 15 minutes
         schedulePeriodicTask(taskIdentifier: task.identifier, earliestBeginInSeconds: earliestBeginInSeconds ?? (15 * 60))
 
+        // Retrieve the stored inputData for this periodic task
+        let storedInputData = UserDefaultsHelper.getStoredPeriodicTaskInputData(forTaskIdentifier: task.identifier)
+
         let operationQueue = OperationQueue()
         let operation = createBackgroundOperation(
             identifier: task.identifier,
-            inputData: nil,
+            inputData: storedInputData,
             backgroundMode: .backgroundPeriodicTask(identifier: identifier)
         )
 
@@ -191,6 +194,13 @@ public class WorkmanagerPlugin: FlutterPluginAppLifeCycleDelegate, FlutterPlugin
 
         executeIfSupportedVoid(completion: completion, feature: "PeriodicTask") {
             let initialDelaySeconds = Double(request.initialDelaySeconds ?? 0)
+
+            // Store the inputData for later retrieval when the task executes
+            UserDefaultsHelper.storePeriodicTaskInputData(
+                request.inputData as? [String: Any],
+                forTaskIdentifier: request.uniqueName
+            )
+
             WorkmanagerPlugin.schedulePeriodicTask(
                 taskIdentifier: request.uniqueName,
                 earliestBeginInSeconds: initialDelaySeconds