[ios] [WiP] #5036 draggable annotation views

platform/darwin/src/MGLAnnotation.h

@@ -27,7 +27,7 @@ NS_ASSUME_NONNULL_BEGIN
  The center point (specified as a map coordinate) of the annotation. (required)
  (read-only)
  */
-@property (nonatomic, readonly) CLLocationCoordinate2D coordinate;
+@property (nonatomic, readwrite) CLLocationCoordinate2D coordinate;
 
 @optional
 

platform/ios/app/MBXAnnotationView.m

@@ -25,4 +25,33 @@ - (void)setCenterColor:(UIColor *)centerColor {
     }
 }
 
+- (void)setDragState:(MGLAnnotationViewDragState)dragState animated:(BOOL)animated
+{
+    [super setDragState:dragState animated:NO];
+
+    switch (dragState) {
+        case MGLAnnotationViewDragStateNone:
+            break;
+        case MGLAnnotationViewDragStateStarting: {
+            [UIView animateWithDuration:.4 delay:0 usingSpringWithDamping:.4 initialSpringVelocity:.5 options:UIViewAnimationOptionCurveLinear animations:^{
+                self.transform = CGAffineTransformScale(CGAffineTransformIdentity, 2, 2);
+            } completion:nil];
+            break;
+        }
+        case MGLAnnotationViewDragStateDragging:
+            break;
+        case MGLAnnotationViewDragStateCanceling:
+            break;
+        case MGLAnnotationViewDragStateEnding: {
+            [UIView animateWithDuration:.4 delay:0 usingSpringWithDamping:.4 initialSpringVelocity:.5 options:UIViewAnimationOptionCurveLinear animations:^{
+                self.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1, 1);
+            } completion:nil];
+            break;
+        }
+    }
+
+}
+
+
+
 @end

platform/ios/app/MBXViewController.m

@@ -409,6 +409,7 @@ - (void)presentAnnotationWithCustomCallout
 
 - (IBAction)handleLongPress:(UILongPressGestureRecognizer *)longPress
 {
+    /*
     if (longPress.state == UIGestureRecognizerStateBegan)
     {
         CGPoint point = [longPress locationInView:longPress.view];
@@ -427,7 +428,7 @@ - (IBAction)handleLongPress:(UILongPressGestureRecognizer *)longPress
         pin.subtitle = [[[MGLCoordinateFormatter alloc] init] stringFromCoordinate:pin.coordinate];
         // Calling `addAnnotation:` on mapView is not required since `selectAnnotation:animated` has the side effect of adding the annotation if required
         [self.mapView selectAnnotation:pin animated:YES];
-    }
+    }*/
 }
 
 - (IBAction)cycleStyles:(__unused id)sender
@@ -586,7 +587,12 @@ - (MGLAnnotationView *)mapView:(MGLMapView *)mapView viewForAnnotation:(id<MGLAn
         annotationView = [[MBXAnnotationView alloc] initWithReuseIdentifier:MBXViewControllerAnnotationViewReuseIdentifer];
         annotationView.frame = CGRectMake(0, 0, 10, 10);
         annotationView.centerColor = [UIColor whiteColor];
-
+
+        // uncomment to make the annotation view draggable
+        // also note that having two long press gesture recognizers on overlapping views (`self.view` & `annotationView`) will cause weird behaviour
+        // comment out the pin dropping functionality in the handleLongPress: method in this class to make draggable annotation views play nice
+        annotationView.draggable = YES;
+
         // uncomment to flatten the annotation view against the map when the map is tilted
         // this currently causes severe performance issues when more than 2k annotations are visible
         // annotationView.flat = YES;

platform/ios/src/MGLAnnotationView.h

@@ -4,6 +4,14 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+typedef NS_ENUM(NSUInteger, MGLAnnotationViewDragState) {
+    MGLAnnotationViewDragStateNone = 0,     // View is sitting on the map
+    MGLAnnotationViewDragStateStarting,     // View is beginning to drag and animation starts
+    MGLAnnotationViewDragStateDragging,     // View is being dragged
+    MGLAnnotationViewDragStateCanceling,    // View dragging was cancelled and will be returned to its starting positon.
+    MGLAnnotationViewDragStateEnding        // View was dragged, new coordinate has been set and stop animation is finishing
+};
+
 /** The MGLAnnotationView class is responsible for representing point-based annotation markers as a view. Annotation views represent an annotation object, which is an object that corresponds to the MGLAnnotation protocol. When an annotation’s coordinate point is visible on the map view, the map view delegate is asked to provide a corresponding annotation view. If an annotation view is created with a reuse identifier, the map view may recycle the view when it goes offscreen. */
 @interface MGLAnnotationView : UIView
 
@@ -48,6 +56,23 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property (nonatomic, assign, getter=isScaledWithViewingDistance) BOOL scalesWithViewingDistance;
 
+/**
+ Setting this property to YES will make the view draggable. Long press followed by a pan gesture will start to move the
+ view around the map. Each update will center the annotation view. setCoordinate: is called on the associated annotation when panning ends successfully.
+ */
+@property (nonatomic, assign, getter=isDraggable) BOOL draggable;
+
+/**
+ All states are handled automatically when `draggable` is set to YES.
+ Custom animations can be achieved by overriding setDragState:animated:
+ */
+@property (nonatomic, readonly) MGLAnnotationViewDragState dragState;
+
+/**
+ Implementer may override this method to use a custom animation for the different MGLAnnotationViewDragState.
+ */
+- (void)setDragState:(MGLAnnotationViewDragState)dragState animated:(BOOL)animated __attribute__((objc_requires_super));
+
 /**
  Called when the view is removed from the reuse queue.
 

platform/ios/src/MGLAnnotationView.mm

@@ -6,10 +6,13 @@
 
 #include <mbgl/util/constants.hpp>
 
-@interface MGLAnnotationView ()
+@interface MGLAnnotationView () <UIGestureRecognizerDelegate>
 
 @property (nonatomic) id<MGLAnnotation> annotation;
 @property (nonatomic, readwrite, nullable) NSString *reuseIdentifier;
+@property (nonatomic, weak) UIPanGestureRecognizer *panGestureRecognizer;
+@property (nonatomic, weak) UILongPressGestureRecognizer *longPressRecognizer;
+@property (nonatomic, weak) MGLMapView *mapView;
 
 @end
 
@@ -49,6 +52,11 @@ - (void)setCenter:(CGPoint)center pitch:(CGFloat)pitch
 
     [super setCenter:center];
 
+    // Omit applying a new transformation while the view is being dragged.
+    if (self.dragState == MGLAnnotationViewDragStateDragging) {
+        return;
+    }
+
     if (self.flat)
     {
         [self updatePitch:pitch];
@@ -95,6 +103,129 @@ - (void)updateScaleForPitch:(CGFloat)pitch
     }
 }
 
+- (void)setDraggable:(BOOL)draggable
+{
+    _draggable = draggable;
+    if (draggable) {
+        [self enableDrag];
+    } else {
+        [self disableDrag];
+    }
+}
+
+- (void)enableDrag
+{
+    if (!_longPressRecognizer) {
+        UILongPressGestureRecognizer *recognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)];
+        recognizer.delegate = self;
+        [self addGestureRecognizer:recognizer];
+        _longPressRecognizer = recognizer;
+    }
+
+    if (!_panGestureRecognizer) {
+        UIPanGestureRecognizer *recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
+        recognizer.delegate = self;
+        [self addGestureRecognizer:recognizer];
+        _panGestureRecognizer = recognizer;
+    }
+}
+
+- (void)disableDrag
+{
+    [self removeGestureRecognizer:_longPressRecognizer];
+    [self removeGestureRecognizer:_panGestureRecognizer];
+}
+
+- (void)handleLongPress:(UILongPressGestureRecognizer *)sender
+{
+    if (sender.state == UIGestureRecognizerStateBegan)
+    {
+        self.dragState = MGLAnnotationViewDragStateStarting;
+    }
+    else if (sender.state == UIGestureRecognizerStateChanged)
+    {
+        self.dragState = MGLAnnotationViewDragStateDragging;
+    }
+    else if (sender.state == UIGestureRecognizerStateCancelled) {
+        self.dragState = MGLAnnotationViewDragStateCanceling;
+    }
+    else if (sender.state == UIGestureRecognizerStateEnded)
+    {
+        self.dragState = MGLAnnotationViewDragStateEnding;
+    }
+}
+
+- (void)handlePan:(UIPanGestureRecognizer *)sender
+{
+    CGPoint center = [sender locationInView:sender.view.superview];
+    [self setCenter:center pitch:self.mapView.camera.pitch];
+
+    if (sender.state == UIGestureRecognizerStateEnded) {
+        self.dragState = MGLAnnotationViewDragStateNone;
+    }
+}
+
+- (void)setDragState:(MGLAnnotationViewDragState)dragState
+{
+    [self setDragState:dragState animated:YES];
+}
+
+- (void)setDragState:(MGLAnnotationViewDragState)dragState animated:(BOOL)animated
+{
+    _dragState = dragState;
+
+    switch (dragState) {
+        case MGLAnnotationViewDragStateNone:
+            break;
+        case MGLAnnotationViewDragStateStarting: {
+            if (animated)
+            {
+                [UIView animateWithDuration:.20 animations:^{
+                    self.transform = CGAffineTransformScale(CGAffineTransformIdentity, 2, 2);
+                }];
+            }
+            break;
+        }
+        case MGLAnnotationViewDragStateDragging:
+            break;
+        case MGLAnnotationViewDragStateCanceling:
+            break;
+        case MGLAnnotationViewDragStateEnding: {
+
+            CLLocationCoordinate2D coord = [self.mapView convertPoint:self.center toCoordinateFromView:self.mapView];
+            [self.annotation setCoordinate:coord];
+
+            if (animated)
+            {
+                [UIView animateWithDuration:.20 animations:^{
+                    self.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1, 1);
+                } completion:^(BOOL finished) {
+                    self.dragState = MGLAnnotationViewDragStateNone;
+                }];
+            }
+            else
+            {
+                _dragState = MGLAnnotationViewDragStateNone;
+            }
+            break;
+        }
+    }
+}
+
+- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
+{
+    BOOL isDragging = self.dragState == MGLAnnotationViewDragStateDragging;
+    if ([gestureRecognizer isKindOfClass:UIPanGestureRecognizer.class] && !(isDragging)) {
+        return NO;
+    }
+    return YES;
+}
+
+- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
+{
+    return YES;
+}
+
 - (id<CAAction>)actionForLayer:(CALayer *)layer forKey:(NSString *)event
 {
     // Allow mbgl to drive animation of this view’s bounds.

platform/ios/src/MGLAnnotationView_Private.h

@@ -3,10 +3,13 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+@class MGLMapView;
+
 @interface MGLAnnotationView (Private)
 
 @property (nonatomic) id<MGLAnnotation> annotation;
 @property (nonatomic, readwrite, nullable) NSString *reuseIdentifier;
+@property (nonatomic, weak) MGLMapView *mapView;
 
 - (void)setCenter:(CGPoint)center pitch:(CGFloat)pitch;
 

platform/ios/src/MGLMapView.mm

@@ -4507,6 +4507,7 @@ - (void)updateAnnotationViews
         else
         {
             CGPoint center = [self convertCoordinate:annotationContext.annotation.coordinate toPointToView:self];
+            annotationView.mapView = self;
             [annotationView setCenter:center pitch:self.camera.pitch];
         }
     }