Fix Constants.topBarHeight (#5252)

This approach is still not ideal as it assumes there's a visible stack somewhere in the Hierarchy.
It's better than the current implementation so I'm pushing it and will reiterate in the future if needed.

lib/ios/Constants.m

@@ -1,4 +1,5 @@
 #import "Constants.h"
+#import "UIViewController+LayoutProtocol.h"
 
 @implementation Constants
 
@@ -7,7 +8,7 @@ + (NSDictionary *)getConstants {
 }
 
 + (CGFloat)topBarHeight {
-	return UIApplication.sharedApplication.delegate.window.rootViewController.navigationController.navigationBar.frame.size.height;
+	return [UIApplication .sharedApplication.delegate.window.rootViewController getTopBarHeight];
 }
 
 + (CGFloat)statusBarHeight {

lib/ios/RNNLayoutProtocol.h

@@ -21,6 +21,8 @@ typedef void (^RNNReactViewReadyCompletionBlock)(void);
 
 - (UIViewController<RNNLayoutProtocol> *)getCurrentChild;
 
+- (CGFloat) getTopBarHeight;
+
 - (void)mergeOptions:(RNNNavigationOptions *)options;
 
 - (RNNNavigationOptions *)resolveOptions;

lib/ios/RNNNavigationController.m

@@ -21,6 +21,10 @@ - (UIViewController *)getCurrentChild {
 	return self.topViewController;
 }
 
+- (CGFloat)getTopBarHeight {
+    return self.navigationBar.frame.size.height;
+}
+
 - (UIInterfaceOrientationMask)supportedInterfaceOrientations {
 	return self.getCurrentChild.supportedInterfaceOrientations;
 }

lib/ios/RNNRootViewController.m

@@ -1,8 +1,4 @@
 #import "RNNRootViewController.h"
-#import <React/RCTConvert.h>
-#import "RNNAnimator.h"
-#import "RNNPushAnimation.h"
-#import "RNNReactView.h"
 #import "RNNAnimationsTransitionDelegate.h"
 #import "UIViewController+LayoutProtocol.h"
 
@@ -93,6 +89,10 @@ - (UIViewController *)getCurrentChild {
 	return nil;
 }
 
+- (CGFloat)getTopBarHeight {
+    return [[self getCurrentChild] getTopBarHeight];
+}
+
 -(void)updateSearchResultsForSearchController:(UISearchController *)searchController {
 	[self.eventEmitter sendOnSearchBarUpdated:self.layoutInfo.componentId
 										 text:searchController.searchBar.text

lib/ios/RNNSideMenuController.m

@@ -1,6 +1,4 @@
 #import "RNNSideMenuController.h"
-#import "RNNSideMenuChildVC.h"
-#import "MMDrawerController.h"
 #import "MMDrawerVisualState.h"
 
 @interface RNNSideMenuController ()
@@ -92,7 +90,6 @@ - (void)side:(MMDrawerSide)side enabled:(BOOL)enabled {
 
 -(void)setControllers:(NSArray*)controllers {
 	for (id controller in controllers) {
-
 		if ([controller isKindOfClass:[RNNSideMenuChildVC class]]) {
 			RNNSideMenuChildVC *child = (RNNSideMenuChildVC*)controller;
 
@@ -133,12 +130,19 @@ - (UIViewController *)openedViewController {
 			return self.right;
 		default:
 			return self.center;
-			break;
 	}
 }
 
 - (UIViewController<RNNLayoutProtocol> *)getCurrentChild {
 	return self.center;
 }
 
+- (CGFloat)getTopBarHeight {
+    for(UIViewController * child in [self childViewControllers]) {
+        CGFloat childTopBarHeight = [child getTopBarHeight];
+        if (childTopBarHeight > 0) return childTopBarHeight;
+    }
+    return [super getTopBarHeight];
+}
+
 @end

lib/ios/RNNTabBarController.m

@@ -12,6 +12,14 @@ - (UIViewController *)getCurrentChild {
 	return self.selectedViewController;
 }
 
+- (CGFloat)getTopBarHeight {
+    for(UIViewController * child in [self childViewControllers]) {
+        CGFloat childTopBarHeight = [child getTopBarHeight];
+        if (childTopBarHeight > 0) return childTopBarHeight;
+    }
+    return [super getTopBarHeight];
+}
+
 - (UIInterfaceOrientationMask)supportedInterfaceOrientations {
 	return self.selectedViewController.supportedInterfaceOrientations;
 }

lib/ios/UIViewController+LayoutProtocol.m

@@ -70,6 +70,10 @@ - (UIViewController *)getCurrentChild {
 	return nil;
 }
 
+- (CGFloat)getTopBarHeight {
+    return 0;
+}
+
 - (void)onChildWillAppear {
 	[self.presenter applyOptions:self.resolveOptions];
 	[((UISplitViewController *)self.parentViewController) onChildWillAppear];

playground/src/services/Navigation.js

@@ -33,6 +33,8 @@ const compId = (selfOrCompId) => {
   return get(selfOrCompId, 'props.componentId', selfOrCompId);
 }
 
+const constants = Navigation.constants;
+
 module.exports = {
   mergeOptions,
   push,
@@ -49,5 +51,6 @@ module.exports = {
   setDefaultOptions: Navigation.setDefaultOptions.bind(Navigation),
   setRoot: Navigation.setRoot.bind(Navigation),
   TouchablePreview: Navigation.TouchablePreview,
-  setStackRoot
+  setStackRoot,
+  constants
 }