Support launch storyboards as splash screens on iOS (#1165)

* Support launch storyboards as splash screens

ios/RCCManager.m

@@ -158,91 +158,159 @@
   self.bundleURL = bundleURL;
   self.sharedBridge = [[RCTBridge alloc] initWithDelegate:self launchOptions:launchOptions];
   
-  [self showSplashScreen];
+  [[self class] showSplashScreen];
 }
 
--(void)showSplashScreen
+-(RCTBridge*)getBridge
+{
+  return self.sharedBridge;
+}
+
+-(UIWindow*)getAppWindow
+{
+  UIApplication *app = [UIApplication sharedApplication];
+  UIWindow *window = (app.keyWindow != nil) ? app.keyWindow : app.windows[0];
+  return window;
+}
+
+#pragma mark - Splash Screen
+
++ (void)showSplashScreen
 {
+  
+  UIViewController* viewControllerFromLaunchStoryboard;
+  viewControllerFromLaunchStoryboard = [self viewControllerFromLaunchStoryboard];
+  if (viewControllerFromLaunchStoryboard)
+  {
+    [self showSplashScreenViewController:viewControllerFromLaunchStoryboard];
+    return;
+  }
+  
   CGRect screenBounds = [UIScreen mainScreen].bounds;
-  UIView *splashView = nil;
+  UIViewController* viewControllerFromLaunchNib = [self viewControllerFromLaunchNibForScreenBounds:screenBounds];
+  if (viewControllerFromLaunchNib)
+  {
+    [self showSplashScreenViewController:viewControllerFromLaunchNib];
+    return;
+  }
+  
+  UIViewController* viewControllerFromLaunchImage = [self viewControllerFromLaunchImageForScreenBounds:screenBounds];
+  if (viewControllerFromLaunchImage)
+  {
+    [self showSplashScreenViewController:viewControllerFromLaunchImage];
+    return;
+  }
+  
+  UIViewController* viewController = [[UIViewController alloc] init];
+  viewController.view.frame = screenBounds;
+  viewController.view.backgroundColor = [UIColor whiteColor];
+  
+  [self showSplashScreenViewController:viewController];
+}
+
++ (UIViewController *)viewControllerFromLaunchStoryboard
+{
+  NSString* launchStoryboardName = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"UILaunchStoryboardName"];
+  if (launchStoryboardName == nil)
+  {
+    return nil;
+  }
+  
+  UIStoryboard* storyboard = [UIStoryboard storyboardWithName:launchStoryboardName bundle:nil];
+  if (storyboard == nil)
+  {
+    return nil;
+  }
+  
+  return storyboard.instantiateInitialViewController;
+}
+
++ (UIViewController *)viewControllerFromLaunchNibForScreenBounds:(CGRect)screenBounds
+{
+  NSString* launchStoryboardName = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"UILaunchStoryboardName"];
+  if (launchStoryboardName == nil)
+  {
+    return nil;
+  }
   
-  NSString* launchStoryBoard = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"UILaunchStoryboardName"];
-  if (launchStoryBoard != nil)
-  {//load the splash from the storyboard that's defined in the info.plist as the LaunchScreen
-    @try
+  @try {
+    id nibContents = [[NSBundle mainBundle] loadNibNamed:launchStoryboardName owner:self options:nil];
+    if (!nibContents || [nibContents count] == 0)
     {
-      splashView = [[NSBundle mainBundle] loadNibNamed:launchStoryBoard owner:self options:nil][0];
-      if (splashView != nil)
-      {
-        splashView.frame = CGRectMake(0, 0, screenBounds.size.width, screenBounds.size.height);
-      }
+      return nil;
     }
-    @catch(NSException *e)
+    
+    id firstObject = [nibContents firstObject];
+    if (![firstObject isKindOfClass:[UIView class]])
     {
-      splashView = nil;
+      return nil;
     }
+    
+    UIViewController* viewController = [[UIViewController alloc] init];
+    viewController.view = (UIView *)firstObject;
+    viewController.view.frame = screenBounds;
+    return viewController;
+  }
+  @catch(NSException *exception) {
+    return nil;
   }
-  else
-  {//load the splash from the DEfault image or from LaunchImage in the xcassets
-    CGFloat screenHeight = screenBounds.size.height;
+}
+
++ (UIViewController *)viewControllerFromLaunchImageForScreenBounds:(CGRect)screenBounds
+{
+  //load the splash from the default image or from LaunchImage in the xcassets
+  
+  CGFloat screenHeight = screenBounds.size.height;
+  
+  NSString* imageName = @"Default";
+  if (screenHeight == 568)
+    imageName = [imageName stringByAppendingString:@"-568h"];
+  else if (screenHeight == 667)
+    imageName = [imageName stringByAppendingString:@"-667h"];
+  else if (screenHeight == 736)
+    imageName = [imageName stringByAppendingString:@"-736h"];
+  
+  //xcassets LaunchImage files
+  UIImage *image = [UIImage imageNamed:imageName];
+  if (image == nil)
+  {
+    imageName = @"LaunchImage";
     
-    NSString* imageName = @"Default";
+    if (screenHeight == 480)
+      imageName = [imageName stringByAppendingString:@"-700"];
     if (screenHeight == 568)
-      imageName = [imageName stringByAppendingString:@"-568h"];
+      imageName = [imageName stringByAppendingString:@"-700-568h"];
     else if (screenHeight == 667)
-      imageName = [imageName stringByAppendingString:@"-667h"];
+      imageName = [imageName stringByAppendingString:@"-800-667h"];
     else if (screenHeight == 736)
-      imageName = [imageName stringByAppendingString:@"-736h"];
+      imageName = [imageName stringByAppendingString:@"-800-Portrait-736h"];
+    else if (screenHeight == 812)
+      imageName = [imageName stringByAppendingString:@"-1100-Portrait-2436h"];
+    else if (screenHeight == 1024)
+      imageName = [imageName stringByAppendingString:@"-Portrait"];
     
-    //xcassets LaunchImage files
-    UIImage *image = [UIImage imageNamed:imageName];
-    if (image == nil)
-    {
-      imageName = @"LaunchImage";
-      
-      if (screenHeight == 480)
-        imageName = [imageName stringByAppendingString:@"-700"];
-      if (screenHeight == 568)
-        imageName = [imageName stringByAppendingString:@"-700-568h"];
-      else if (screenHeight == 667)
-        imageName = [imageName stringByAppendingString:@"-800-667h"];
-      else if (screenHeight == 736)
-        imageName = [imageName stringByAppendingString:@"-800-Portrait-736h"];
-      else if (screenHeight == 812)
-        imageName = [imageName stringByAppendingString:@"-1100-Portrait-2436h"];
-      else if (screenHeight == 1024)
-        imageName = [imageName stringByAppendingString:@"-Portrait"];
-
-      image = [UIImage imageNamed:imageName];
-    }
-    
-    if (image != nil)
-    {
-      splashView = [[UIImageView alloc] initWithImage:image];
-    }
+    image = [UIImage imageNamed:imageName];
   }
   
-  if (splashView != nil)
+  if (image == nil)
   {
-    UIViewController *splashVC = [[UIViewController alloc] init];
-    splashVC.view = splashView;
-    
-    id<UIApplicationDelegate> appDelegate = [UIApplication sharedApplication].delegate;
-    appDelegate.window.rootViewController = splashVC;
-    [appDelegate.window makeKeyAndVisible];
+    return nil;
   }
+  
+  UIViewController* viewController = [[UIViewController alloc] init];
+  
+  UIImageView* imageView = [[UIImageView alloc] initWithImage:image];
+  viewController.view = imageView;
+  viewController.view.frame = screenBounds;
+  
+  return viewController;
 }
 
--(RCTBridge*)getBridge
-{
-  return self.sharedBridge;
-}
-
--(UIWindow*)getAppWindow
++ (void)showSplashScreenViewController:(UIViewController *)viewController
 {
-  UIApplication *app = [UIApplication sharedApplication];
-  UIWindow *window = (app.keyWindow != nil) ? app.keyWindow : app.windows[0];
-  return window;
+  id<UIApplicationDelegate> appDelegate = [UIApplication sharedApplication].delegate;
+  appDelegate.window.rootViewController = viewController;
+  [appDelegate.window makeKeyAndVisible];
 }
 
 -(NSDictionary*)getAppStyle