Initial commit.

Author: levigroker

.gitignore

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+*.lock
+.DS_Store
+xcuserdata
+project.xcworkspace
+Build

GRKContainerViewController.podspec

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+Pod::Spec.new do |s|
+  s.name         = "GRKContainerViewController"
+  s.version      = "1.0"
+  s.summary      = "A simple container view controller used to easily swap contained controllers with optional animation."
+  s.description  = <<-DESC
+		A container UIViewController providing the ability to easily transition from one contained view controller to another.
+    DESC
+  s.homepage     = "https://github.com/levigroker/GRKContainerViewController"
+  s.license      = 'Creative Commons Attribution 3.0 Unported License'
+  s.author       = { "Levi Brown" => "[email protected]" }
+  s.social_media_url = 'https://twitter.com/levigroker'
+  s.source       = { :git => "https://github.com/levigroker/GRKContainerViewController.git", :tag => "1.0" }
+  s.platform     = :ios, '7.1'
+  s.ios.deployment_target = '6.0'
+  s.source_files = 'GRKContainerViewController/**/*.{h,m}'
+  s.requires_arc = true
+end

GRKContainerViewController/GRKContainerViewController.h

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+//
+//  GRKContainerViewController.h
+//
+//  Created by Levi Brown on November 23, 2013.
+//  Copyright (c) 2013, 2014 Levi Brown <mailto:[email protected]>
+//  This work is licensed under the Creative Commons Attribution 3.0
+//  Unported License. To view a copy of this license, visit
+//  http://creativecommons.org/licenses/by/3.0/ or send a letter to Creative
+//  Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041,
+//  USA.
+//
+//  The above attribution and the included license must accompany any version
+//  of the source code. Visible attribution in any binary distributable
+//  including this work (or derivatives) is not required, but would be
+//  appreciated.
+//
+
+#import <UIKit/UIKit.h>
+
+/**
+ *  The default animation duration for the transition to the new view controller.
+ */
+extern NSTimeInterval const kDefaultAnimationDuration;
+
+///
+/// @name GRKContainerViewController
+///
+
+@interface GRKContainerViewController : UIViewController
+
+/**
+ *  The current view controller. Changes to this property will not be animated.
+ */
+@property (nonatomic,strong) UIViewController *viewController;
+
+/**
+ *  The animation duration to use for the transition animation (if applicable). Defaults to `kDefaultAnimationDuration`.
+ *  @see kDefaultAnimationDuration
+ */
+@property (nonatomic,assign) NSTimeInterval transitionAnimationDuration;
+
+/**
+ *  Set the currently displayed view controller with an optional cross fade animation and completion handler.
+ *
+ *  @param viewController The new view controler to be displayed.
+ *  @param animated       If YES then a simple cross fade animation will be applied during the tranistion from the current view controller to the new view controller.
+ *  @param completion     A block to be called once the new view controller is displayed (after any animations). This can be `nil`.
+ */
+- (void)setViewController:(UIViewController *)viewController animated:(BOOL)animated completion:(void(^)(UIViewController *viewController))completion;
+
+@end

GRKContainerViewController/GRKContainerViewController.m

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+//
+//  GRKContainerViewController.h
+//
+//  Created by Levi Brown on November 23, 2013.
+//  Copyright (c) 2013, 2014 Levi Brown <mailto:[email protected]>
+//  This work is licensed under the Creative Commons Attribution 3.0
+//  Unported License. To view a copy of this license, visit
+//  http://creativecommons.org/licenses/by/3.0/ or send a letter to Creative
+//  Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041,
+//  USA.
+//
+//  The above attribution and the included license must accompany any version
+//  of the source code. Visible attribution in any binary distributable
+//  including this work (or derivatives) is not required, but would be
+//  appreciated.
+//
+
+#import "GRKContainerViewController.h"
+
+NSTimeInterval const kDefaultAnimationDuration = 0.5f;
+
+@implementation GRKContainerViewController
+
+#pragma mark - Lifecycle
+
+- (instancetype)init
+{
+    if ((self = [super init]))
+    {
+        [self setup];
+    }
+    
+    return self;
+}
+
+- (instancetype)initWithCoder:(NSCoder *)aDecoder
+{
+    if ((self = [super initWithCoder:aDecoder]))
+    {
+        [self setup];
+    }
+    
+    return self;
+}
+
+- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
+{
+    if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]))
+    {
+        [self setup];
+    }
+    
+    return self;
+}
+
+- (void)setup
+{
+    _transitionAnimationDuration = kDefaultAnimationDuration;
+}
+
+#pragma mark - API Implementation
+
+- (void)setViewController:(UIViewController *)viewController animated:(BOOL)animated completion:(void(^)(UIViewController *viewController))completion
+{
+    //Ensure the view is loaded
+    [self view];
+    
+    //We will use a simple cross fade animation, as indicated
+    NSTimeInterval duration = animated ? self.transitionAnimationDuration : 0.0f;
+    
+    //Set the new view controller's view to be transparent
+    viewController.view.alpha = 0.0f;
+    
+    //Add the new view controller to the view and view controller hierarchies
+    if (viewController)
+    {
+        [self addChildViewController:viewController];
+        [self.view addSubview:viewController.view];
+        [viewController didMoveToParentViewController:self];
+
+        //Setup constraints to keep the new view pinned to our size.
+        UIView *containedView = viewController.view;
+        containedView.translatesAutoresizingMaskIntoConstraints = NO;
+        [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[containedView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(containedView)]];
+        [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[containedView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(containedView)]];
+    }
+    
+    [UIView animateWithDuration:duration animations:^{
+        //Set the new view controller's view to be visible
+        viewController.view.alpha = 1.0f;
+    } completion:^(BOOL finished) {
+        //Remove the previous view controller from the view and view controller hierarchies
+        [self.viewController willMoveToParentViewController:nil];
+        [self.viewController.view removeFromSuperview];
+        [self.viewController removeFromParentViewController];
+
+        //Keep our new view controller
+        _viewController = viewController;
+        
+        if (completion)
+        {
+            //Call the completion block with the new view controller
+            completion(self.viewController);
+        }
+    }];
+}
+
+#pragma mark - Accessors
+
+- (void)setViewController:(UIViewController *)viewController
+{
+    [self setViewController:viewController animated:NO completion:nil];
+}
+
+@end