Fix strong mode errors

.analysis_options

@@ -1,2 +1,7 @@
 analyzer:
-  strong-mode: true
+  strong-mode: true
+linter:
+  rules:
+    - annotate_overrides
+    - cancel_subscriptions
+    - close_sinks

CHANGELOG.md

@@ -1,6 +1,11 @@
 # Changelog
 
 
+## Version 0.4.0 (2017-06-27)
+
+* Fix strong mode errors (#20).
+
+
 ## Version 0.3.6 (2017-06-06)
 
 * Fix bug: Provide reasonable fallback for event target when mouse position exits viewport (#19).

lib/dnd.dart

@@ -11,4 +11,3 @@ part 'src/draggable_dispatch.dart';
 part 'src/draggable_manager.dart';
 part 'src/dropzone.dart';
 part 'src/dropzone_acceptor.dart';
-

lib/src/draggable.dart

@@ -6,7 +6,6 @@ part of dnd;
 /// the [CustomEvent]s.
 _DragInfo _currentDrag;
 
-
 /// The [Draggable] detects drag operations for touch and mouse interactions and
 /// optionally creates a drag avatar for visual feedback of the drag. Event
 /// streams are provided to track touch or mouse dragging:
@@ -17,7 +16,6 @@ _DragInfo _currentDrag;
 ///
 /// A [Draggable] can be created for one [Element] or an [ElementList].
 class Draggable {
-
   /// Counter to generate a unique id for each instance.
   static int idCounter = 0;
 
@@ -72,17 +70,17 @@ class Draggable {
   /// will also be fired.
   Stream<DraggableEvent> get onDragStart {
     if (_onDragStart == null) {
-      _onDragStart = new StreamController<DraggableEvent>.broadcast(sync: true,
-          onCancel: () => _onDragStart = null);
+      _onDragStart = new StreamController<DraggableEvent>.broadcast(
+          sync: true, onCancel: () => _onDragStart = null);
     }
     return _onDragStart.stream;
   }
 
   /// Fired periodically throughout the drag operation.
   Stream<DraggableEvent> get onDrag {
     if (_onDrag == null) {
-      _onDrag = new StreamController<DraggableEvent>.broadcast(sync: true,
-          onCancel: () => _onDrag = null);
+      _onDrag = new StreamController<DraggableEvent>.broadcast(
+          sync: true, onCancel: () => _onDrag = null);
     }
     return _onDrag.stream;
   }
@@ -91,8 +89,8 @@ class Draggable {
   /// Is also fired when the user clicks the 'esc'-key or the window loses focus.
   Stream<DraggableEvent> get onDragEnd {
     if (_onDragEnd == null) {
-      _onDragEnd = new StreamController<DraggableEvent>.broadcast(sync: true,
-          onCancel: () => _onDragEnd = null);
+      _onDragEnd = new StreamController<DraggableEvent>.broadcast(
+          sync: true, onCancel: () => _onDragEnd = null);
     }
     return _onDragEnd.stream;
   }
@@ -150,28 +148,24 @@ class Draggable {
   /// The [draggingClassBody] is the css class set to the html body tag
   /// during a drag. If set to null, no such css class is added.
   Draggable(elementOrElementList,
-      { this.avatarHandler: null,
-        this.horizontalOnly: false,
-        this.verticalOnly: false,
-        this.handle: null,
-        this.cancel: 'input, textarea, button, select, option',
-        this.draggingClass: 'dnd-dragging',
-        this.draggingClassBody: 'dnd-drag-occurring'})
-
+      {this.avatarHandler: null,
+      this.horizontalOnly: false,
+      this.verticalOnly: false,
+      this.handle: null,
+      this.cancel: 'input, textarea, button, select, option',
+      this.draggingClass: 'dnd-dragging',
+      this.draggingClassBody: 'dnd-drag-occurring'})
       : this._elementOrElementList = elementOrElementList {
-
     // Detect IE Pointer Event Support.
     JsObject jsWindow = new JsObject.fromBrowserObject(window);
     JsObject jsNavigator = jsWindow['navigator'];
 
     if (jsNavigator.hasProperty('pointerEnabled')) {
       // We're on IE11 or higher supporting pointerEvents.
       _eventManagers.add(new _PointerManager(this));
-
-    } else if (jsNavigator.hasProperty('msPointerEnabled')){
+    } else if (jsNavigator.hasProperty('msPointerEnabled')) {
       // We're on IE10 supporting msPointerEvents.
       _eventManagers.add(new _PointerManager(this, msPrefix: true));
-
     } else {
       // We're on other browsers. Install touch and mouse listeners.
       if (TouchEvent.supported) {
@@ -189,7 +183,8 @@ class Draggable {
 
     // Pass event to AvatarHandler.
     if (avatarHandler != null) {
-      avatarHandler._handleDragStart(_currentDrag.element, _currentDrag.position);
+      avatarHandler._handleDragStart(
+          _currentDrag.element, _currentDrag.position);
     }
 
     // Fire the drag start event with start position.
@@ -218,7 +213,8 @@ class Draggable {
   void _handleDrag(UIEvent moveEvent, EventTarget target) {
     // Pass event to AvatarHandler.
     if (avatarHandler != null) {
-      avatarHandler._handleDrag(_currentDrag.startPosition, _currentDrag.position);
+      avatarHandler._handleDrag(
+          _currentDrag.startPosition, _currentDrag.position);
     }
 
     // Dispatch internal drag enter, over, or leave event.
@@ -244,7 +240,8 @@ class Draggable {
     if (_currentDrag.started) {
       // Pass event to AvatarHandler.
       if (avatarHandler != null) {
-        avatarHandler._handleDragEnd(_currentDrag.startPosition, _currentDrag.position);
+        avatarHandler._handleDragEnd(
+            _currentDrag.startPosition, _currentDrag.position);
       }
 
       // Dispatch internal drop event if drag was not cancelled.
@@ -254,8 +251,8 @@ class Draggable {
 
       // Fire dragEnd event.
       if (_onDragEnd != null) {
-        _onDragEnd.add(new DraggableEvent._(event, _currentDrag,
-            cancelled: cancelled));
+        _onDragEnd.add(
+            new DraggableEvent._(event, _currentDrag, cancelled: cancelled));
       }
 
       // Prevent TouchEvent from emulating a click after touchEnd event.
@@ -288,7 +285,8 @@ class Draggable {
   /// [MouseEvent]s. We have to wait for and cancel a potential click event
   /// happening after the mouseUp event.
   void _suppressClickEvent() {
-    StreamSubscription clickPreventer = _elementOrElementList.onClick.listen((event) {
+    StreamSubscription clickPreventer =
+        _elementOrElementList.onClick.listen((event) {
       event.stopPropagation();
       event.preventDefault();
     });
@@ -346,7 +344,6 @@ class Draggable {
   }
 }
 
-
 /// Event used when a drag is detected.
 class DraggableEvent {
   /// The [Element] that is beeing dragged.
@@ -377,7 +374,8 @@ class DraggableEvent {
   final bool cancelled;
 
   /// Private constructor for [DraggableEvent].
-  DraggableEvent._(this.originalEvent, _DragInfo dragInfo, {this.cancelled: false})
+  DraggableEvent._(this.originalEvent, _DragInfo dragInfo,
+      {this.cancelled: false})
       : draggableElement = dragInfo.element,
         avatarHandler = dragInfo.avatarHandler,
         startPosition = dragInfo.startPosition,
@@ -409,9 +407,9 @@ class _DragInfo {
   final bool verticalOnly;
 
   _DragInfo(this.draggableId, this.element, this.startPosition,
-      { this.avatarHandler: null,
-        this.horizontalOnly: false,
-        this.verticalOnly: false}) {
+      {this.avatarHandler: null,
+      this.horizontalOnly: false,
+      this.verticalOnly: false}) {
     // Initially set current position to startPosition.
     _position = startPosition;
   }

lib/src/draggable_avatar.dart

@@ -4,7 +4,6 @@ part of dnd;
 /// a drag avatar. A drag avatar provides visual feedback during the drag
 /// operation.
 abstract class AvatarHandler {
-
   /// Returns the [avatar] element during a drag operation.
   ///
   /// If there is no drag operation going on, [avatar] will be null.
@@ -117,9 +116,12 @@ abstract class AvatarHandler {
     void updateFunction() {
       // Unsing `translate3d` to activate GPU hardware-acceleration (a bit of a hack).
       if (avatar != null) {
-        avatar.style.transform = 'translate3d(${position.x}px, ${position.y}px, 0)';
+        avatar.style.transform =
+            'translate3d(${position.x}px, ${position.y}px, 0)';
       }
-    };
+    }
+
+    ;
 
     // Use request animation frame to update the transform translate.
     AnimationHelper.requestUpdate(updateFunction);
@@ -149,18 +151,16 @@ abstract class AvatarHandler {
   void cacheMargins() {
     // Calculate margins.
     var computedStyles = avatar.getComputedStyle();
-    _marginLeft = num.parse(computedStyles.marginLeft.replaceFirst('px', ''),
-        (s) => 0);
-    _marginTop = num.parse(computedStyles.marginTop.replaceFirst('px', ''),
-        (s) => 0);
+    _marginLeft =
+        num.parse(computedStyles.marginLeft.replaceFirst('px', ''), (s) => 0);
+    _marginTop =
+        num.parse(computedStyles.marginTop.replaceFirst('px', ''), (s) => 0);
   }
 }
 
-
 /// The [OriginalAvatarHandler] uses the draggable element itself as drag
 /// avatar. It uses absolute positioning of the avatar.
 class OriginalAvatarHandler extends AvatarHandler {
-
   Point _draggableStartOffset;
 
   @override
@@ -191,24 +191,22 @@ class OriginalAvatarHandler extends AvatarHandler {
 
     // Set the new position as left/top. Prevent from moving past the top and
     // left borders as the user might not be able to grab the element any more.
-    Point constrainedPosition = new Point(math.max(1, position.x),
-        math.max(1, position.y));
+    Point constrainedPosition =
+        new Point(math.max(1, position.x), math.max(1, position.y));
 
     setLeftTop(constrainedPosition - startPosition + _draggableStartOffset);
   }
 }
 
-
 /// [CloneAvatarHandler] creates a clone of the draggable element as drag avatar.
 /// The avatar is removed at the end of the drag operation.
 class CloneAvatarHandler extends AvatarHandler {
-
   @override
   void dragStart(Element draggable, Point startPosition) {
     // Clone the draggable to create the avatar.
     avatar = (draggable.clone(true) as Element)
-        ..attributes.remove('id')
-        ..style.cursor = 'inherit';
+      ..attributes.remove('id')
+      ..style.cursor = 'inherit';
 
     // Ensure avatar has an absolute position.
     avatar.style.position = 'absolute';
@@ -233,10 +231,8 @@ class CloneAvatarHandler extends AvatarHandler {
   }
 }
 
-
 /// Simple helper class to speed up animation with requestAnimationFrame.
 class AnimationHelper {
-
   static Function _lastUpdateFunction;
   static bool _updating = false;
 
@@ -264,4 +260,4 @@ class AnimationHelper {
       _updating = false;
     }
   }
-}
+}

lib/src/draggable_dispatch.dart

@@ -5,7 +5,6 @@ part of dnd;
 /// Those events are only meant for communication between [Draggable]s and
 /// [Dropzone]s and not to be consumed by users of the library.
 class _DragEventDispatcher {
-
   /// Custom drag enter event that is fired on the element that is entered.
   static const String CUSTOM_DRAG_ENTER = '_customDragEnter';
 
@@ -21,21 +20,20 @@ class _DragEventDispatcher {
   /// Stream provider for [CUSTOM_DRAG_ENTER] events. The relatedTarget contains
   /// the [Element] the user entered from (may be null).
   static EventStreamProvider<MouseEvent> enterEvent =
-       new EventStreamProvider(CUSTOM_DRAG_ENTER);
+      new EventStreamProvider(CUSTOM_DRAG_ENTER);
 
   /// Stream provider for [CUSTOM_DRAG_OVER] events. The relatedTarget is empty.
   static EventStreamProvider<MouseEvent> overEvent =
-       new EventStreamProvider(CUSTOM_DRAG_OVER);
+      new EventStreamProvider(CUSTOM_DRAG_OVER);
 
   /// Stream provider for [CUSTOM_DRAG_LEAVE] events. The relatedTarget contains
   /// the [Element] the user is leaving to (may be null).
   static EventStreamProvider<MouseEvent> leaveEvent =
-       new EventStreamProvider(CUSTOM_DRAG_LEAVE);
+      new EventStreamProvider(CUSTOM_DRAG_LEAVE);
 
   /// Stream provider for [CUSTOM_DROP] events. The relatedTarget is empty.
   static EventStreamProvider<MouseEvent> dropEvent =
-       new EventStreamProvider(CUSTOM_DROP);
-
+      new EventStreamProvider(CUSTOM_DROP);
 
   /// Keeps track of the previous target to be able to fire dragLeave events on it.
   static EventTarget previousTarget;
@@ -45,7 +43,6 @@ class _DragEventDispatcher {
   /// The [draggable] is the [Draggable] that is dispatching the event.
   /// The [target] is the element that the event will be dispatched on.
   static void dispatchEnterOverLeave(Draggable draggable, EventTarget target) {
-
     // Sometimes the target is null (e.g. when user drags over buttons on
     // android). Ignore it.
     if (target == null) {
@@ -56,17 +53,16 @@ class _DragEventDispatcher {
       // Moved on the same element --> dispatch dragOver.
       MouseEvent dragOverEvent = new MouseEvent(CUSTOM_DRAG_OVER);
       target.dispatchEvent(dragOverEvent);
-
     } else {
       // Entered a new element --> fire dragEnter of new element.
-      MouseEvent dragEnterEvent = new MouseEvent(CUSTOM_DRAG_ENTER,
-          relatedTarget: previousTarget);
+      MouseEvent dragEnterEvent =
+          new MouseEvent(CUSTOM_DRAG_ENTER, relatedTarget: previousTarget);
       target.dispatchEvent(dragEnterEvent);
 
       // Fire dragLeave of old element (if there is one).
       if (previousTarget != null) {
-        MouseEvent dragLeaveEvent = new MouseEvent(CUSTOM_DRAG_LEAVE,
-            relatedTarget: target);
+        MouseEvent dragLeaveEvent =
+            new MouseEvent(CUSTOM_DRAG_LEAVE, relatedTarget: target);
         previousTarget.dispatchEvent(dragLeaveEvent);
       }
 
@@ -78,13 +74,11 @@ class _DragEventDispatcher {
     }
   }
 
-
   /// Dispatches drop event.
   ///
   /// The [draggable] is the [Draggable] that is dispatching the event.
   /// The [target] is the element that the event will be dispatched on.
   static void dispatchDrop(Draggable draggable, EventTarget target) {
-
     // Sometimes the target is null (e.g. when user drags over buttons on
     // android). Ignore it.
     if (target == null) {
@@ -106,4 +100,4 @@ class _DragEventDispatcher {
       previousTarget = null;
     }
   }
-}
+}