Merge pull request #1357 from mapbox/1ec5-view-controller

Automatically find view controller for layout guides

include/mbgl/ios/MGLMapView.h

@@ -46,11 +46,6 @@ IB_DESIGNABLE
 
 /** @name Managing Constraints */
 
-/** A view controller whose top and bottom layout guides to use for proper setup of constraints in the map view internals.
-*
-*   Certain components of the map view, such as the heading compass and the data attribution button, need to be aware of the view controller layout in order to avoid positioning content under a top navigation bar or a bottom toolbar. */
-@property (nonatomic, weak) IBOutlet UIViewController *viewControllerForLayoutGuides;
-
 #pragma mark - Accessing Map Properties
 
 /** @name Accessing Map Properties */

ios/app/MBXViewController.mm

@@ -67,7 +67,6 @@ mbgl::Settings_NSUserDefaults *settings = nullptr;
 
     self.mapView = [[MGLMapView alloc] initWithFrame:self.view.bounds accessToken:accessToken];
     self.mapView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
-    self.mapView.viewControllerForLayoutGuides = self;
     self.mapView.showsUserLocation = YES;
     self.mapView.delegate = self;
     [self.view addSubview:self.mapView];

platform/ios/MGLMapView.mm

@@ -323,8 +323,6 @@ mbgl::DefaultFileSource *mbglFileSource = nullptr;
     [container addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleCompassTapGesture:)]];
     [self addSubview:container];
 
-    self.viewControllerForLayoutGuides = nil;
-
     // setup interaction
     //
     _pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanGesture:)];
@@ -476,15 +474,22 @@ mbgl::DefaultFileSource *mbglFileSource = nullptr;
     [self setNeedsUpdateConstraints];
 }
 
-- (void)setViewControllerForLayoutGuides:(UIViewController *)viewController
+- (UIViewController *)viewControllerForLayoutGuides
 {
-    _viewControllerForLayoutGuides = viewController;
-
-    [self.compass.superview removeConstraints:self.compass.superview.constraints];
-    [self.logoBug removeConstraints:self.logoBug.constraints];
-    [self.attributionButton removeConstraints:self.attributionButton.constraints];
-
-    [self setNeedsUpdateConstraints];
+    // Per -[UIResponder nextResponder] documentation, a UIView’s next responder
+    // is its managing UIViewController if applicable, or otherwise its
+    // superview. UIWindow’s next responder is UIApplication, which has no next
+    // responder.
+    UIResponder *laterResponder = self;
+    while ([laterResponder isKindOfClass:[UIView class]])
+    {
+        laterResponder = laterResponder.nextResponder;
+    }
+    if ([laterResponder isKindOfClass:[UIViewController class]])
+    {
+        return (UIViewController *)laterResponder;
+    }
+    return nil;
 }
 
 - (void)updateConstraints
@@ -493,21 +498,20 @@ mbgl::DefaultFileSource *mbglFileSource = nullptr;
     // views so they don't underlap navigation or tool bars. If we don't have a reference, apply
     // constraints against ourself to maintain (albeit less ideal) placement of the subviews.
     //
-    UIView *constraintParentView = (self.viewControllerForLayoutGuides.view ?
-                                    self.viewControllerForLayoutGuides.view :
-                                    self);
+    UIViewController *viewController = self.viewControllerForLayoutGuides;
+    UIView *constraintParentView = (viewController.view ? viewController.view : self);
 
     // compass
     //
     UIView *compassContainer = self.compass.superview;
 
-    if (self.viewControllerForLayoutGuides)
+    if (viewController)
     {
         [constraintParentView addConstraint:
          [NSLayoutConstraint constraintWithItem:compassContainer
                                       attribute:NSLayoutAttributeTop
                                       relatedBy:NSLayoutRelationGreaterThanOrEqual
-                                         toItem:self.viewControllerForLayoutGuides.topLayoutGuide
+                                         toItem:viewController.topLayoutGuide
                                       attribute:NSLayoutAttributeBottom
                                      multiplier:1
                                        constant:5]];
@@ -550,10 +554,10 @@ mbgl::DefaultFileSource *mbglFileSource = nullptr;
 
     // logo bug
     //
-    if (self.viewControllerForLayoutGuides)
+    if (viewController)
     {
         [constraintParentView addConstraint:
-         [NSLayoutConstraint constraintWithItem:self.viewControllerForLayoutGuides.bottomLayoutGuide
+         [NSLayoutConstraint constraintWithItem:viewController.bottomLayoutGuide
                                       attribute:NSLayoutAttributeTop
                                       relatedBy:NSLayoutRelationGreaterThanOrEqual
                                          toItem:self.logoBug
@@ -581,10 +585,10 @@ mbgl::DefaultFileSource *mbglFileSource = nullptr;
 
     // attribution button
     //
-    if (self.viewControllerForLayoutGuides)
+    if (viewController)
     {
         [constraintParentView addConstraint:
-         [NSLayoutConstraint constraintWithItem:self.viewControllerForLayoutGuides.bottomLayoutGuide
+         [NSLayoutConstraint constraintWithItem:viewController.bottomLayoutGuide
                                       attribute:NSLayoutAttributeTop
                                       relatedBy:NSLayoutRelationGreaterThanOrEqual
                                          toItem:self.attributionButton

test/ios/MGLTViewController.m

@@ -12,7 +12,6 @@
 
     _mapView = [[MGLMapView alloc] initWithFrame:self.view.bounds
                                                 accessToken:@"pk.eyJ1IjoianVzdGluIiwiYSI6Ik9RX3RRQzAifQ.dmOg_BAp1ywuDZMM7YsXRg"];
-    _mapView.viewControllerForLayoutGuides = self;
     _mapView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
 
     [self.view addSubview:_mapView];