SToolkitController and Company class.

STabControl.h

// 
//  STabControl.h
//  Xcode Reader
//  
//  Created by Song Hui 2013-4-15
//  Copyright(C)Song Hui. All rights reserved.

#import <UIKit/UIKit.h>

@class STabControl;

@protocol SStabControlDelegate<NSObject>

- (void)tabControl:(STabControl *)tabControl didSelectTabAtIndex:(NSUInteger *)index;

@end

@interface STabControl : UIView

//  Tab images for normal/ unselected state.
@property (nonatomic, strong) NSArray *tabImages;

//  Tab images for selected state.
//  Selected images' size should be the same with normal/ unselected images' respectively.
@property (nonatomic, strong) NSArray *tabSelectedImages;

//  All tabs STabControl owned from left to right order.
@property (nonatomic, strong) NSArray *tabs;

//  Control's delegate.
@property (nonatomic, weak) id<STabControlDelegate> delegate;

//  Designated Initializer
- (id)initWithFrame:(CGRect)frame tabImages:(NSArray *)tabImages tabSelectedImages:(NSArray *)tabSelectedImages;

@end

STabControl.m

// 
//  STabControl.m
//  Xcode Reader
//  
//  Created by Song Hui 2013-4-15
//  Copyright(C)Song Hui. All rights reserved.


#import "STabControl.h"

const NSUInteger kSTabControlAffectiveTouchWidth = 44;

@implementation STabControl

- (id)initWithFrame:(CGRect)frame tabImages:(NSArray *)tabImages tabSelectedImages:(NSArray *)tabSelectedImages
{
    self = [super initWithFrame:frame];
    if (self) {
        self.backgroundColor = [UIColor clearColor];
        _tabImages = tabImages;
        _tabSelectedImages = tabSelectedImages;
    }
    return self;
}

- (void)willMoveToSuperview:(UIView *)superview
{
    [super willMoveToSuperview];
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        if (self.tabImages.count == 0) {
            NSLog(@"STabControl: Tab images empty.");
            return;
        }
        if (self.tabImages.count != self.tabSelectedImages.count) {
            NSLog(@"STabControl: Tab images' count and selected images' count not match.");
            return;
        }
        NSUInteger tabWidth = kSTabControlAffectiveTouchWidth;
        NSUInteger tabHeight = self.frame.size.height;
        NSUInteger horizontalOffset = self.frame.size.width / self.tabImages.count;
        NSUInteger x = (horizontalOffset - tabWidth) / 2;
        NSMutableArray *tabs = [NSMutableArray alloc] initWithCapacity:self.tabImages.count];
        for (NSUInteger i = 0; i < self.tabImages.count; i++) {
            UIButton *tab = [UIButton alloc] initWithFrame:CGRectIntegral(CGRectMake(x, 0, tabWidth, tabHeight))];
            [tab setImage:self.tabImages[i] forState:UIControlStateNormal];
            [tab setImage:self.tabSelectedImages[i] forState:UIControlStateSelected];
            [tab addTarget:self action:@selector(tabTouchUpInside:) forControlStates:UIControlEventTouchUpInsdie];

            //  Calculate tab's image edge insets.
            UIImage *tabImage = self.tabImages[i];
            CGSize tabImageSize = tabImage.size;
            NSUInteger topEdgeInset = floor((tabHeight - tabImageSize.height) / 2);
            NSUInteger leftEdgeInset = floor((tabWidth - tabImageSize.width) / 2);
            NSUInteger bottomEdgeInset = ceil((tabHeight - tabImageSize.height) / 2);
            NSUInteger rightEdgeInset = ceil((tabWidth - tabImageSize.width) / 2);
            tab.imageEdgeInsets = UIEdgeInsetsMake(topEdgeInset, leftEdgeInset, bottomEdgeInset, rightEdgeInset);

            [self addSubview:tab];
            [tabs addObject:tab];
            x += horizontalOffset;
        }
        self.tabs = tabs;
        [self selectTab:self.tabs[0] animated:NO];
    });
}

- (void)selectTab:(UIButton *)selectedTab animated:(BOOL)animated
{
    for (UIButton *tab in self.tabs) {
        if (selectedTab == tab) {
            tab.selected = YES;
            self.selectedIndex = [self.tabs indexOfObject:tab];
        } else {
            tab.selected = NO;
        }
    }
}

- (void)tabTouchUpInside:(UIButton *)tab
{
    [self selectTab:tab animated:NO];
    [self.delegate tabControl:self didSelectTabAtIndex:self.selectedIndex];
}

@end

SToolkitBar.h

//
//  SToolkitBar.h
//  Xcode Reader
//
//  Created by Song Hui 2013-4-11
//  Copyright(C)Song Hui. All rights reserved.
 
#import <UIKit/UIKit.h>
 
@interface SToolkitBar : UIToolbar
 
//  SToolkitBar can have STabControl and UIButton as its items.
//  Before assignment, please ensure each item has correct frame and UIViewAutoResizingMask, so SToolkitBar can layout all items appropriately when device rotate and any other reason causing SToolkitBar's geometry change.
//  FUTURE UPDATE: When UIViewAutoResizingMask cannot achieve the intended layout request. Update maybe require.
@property (nonatomic, strong) NSArray *barItems;
 
//  Designated Initializer is still initWithFrame:. This is just a continent initial method.
- (id)initWithFrame:(CGRect)frame barItems:(NSArray *)barItems backgroundImage:(UIImage *)backgroundImage shadowImage:(UIImage *)shadowImage;

@end

SToolkitBar.m

//
//  SToolkitBar.h
//  Xcode Reader
//
//  Created by Song Hui 2013-4-11
//  Copyright(C)Song Hui. All rights reserved.

#import "SToolkitBar.h"

@implementation SToolkitBar

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
    }
    return self;
}

- (id)initWithFrame:(CGRect)frame barItems:(NSArray *)barItems backgroundImage:(UIImage *)backgroundImage shadowImage:(UIImage *)shadowImage
{
    self = [self initWithFrame:frame];
    if (self) {
        _barItem = barItem;
        [self setBackgroundImage:backgroundImage forToolbarPosition:UIToolbarPositionAny barMetrics:UIBarMetricsDefault];
//      [self setBackgroundImage:backgroundImage forToolbarPosition:UIToolbarPositionAny barMetrics:UIBarMetricsLandscapePhone];
        [self setShadowImage:shadowImage forToolbarPosition:UIToolbarPositionAny barMetrics:UIBarMetricsDefault];
//      [self setShadowImage:shadowImage forToolbarPosition:UIToolbarPositionAny barMetrics:UIBarMetricsLandscapePhone];
        self.autoresizingMask = UIViewAutoresizingMaskFlexibleTopMargin | UIViewAutoresizingFlexibleRightMargin;
    }
    return self;
}

- (void)setBarItems:(NSArray *)barItems
{
    for (id barItem in _barItems) {
        [barItem removeFromSuperView];
    }
    _barItems = barItems;
    for (id barItem in self.barItems) {
        if ([barItem isKindOfClass:[STabControl class]]) {
            [self addSubview:barItem];
        } else ([barItem isKindOfClass:[UIButton class]]) {
            [self addSubview:barItem];
        } else {
            NSLog(@"SToolkitBar: Unacceptable Bar Item Type.");
        }
    }
}

@end

SToolkitController.h

//
//  SToolkitcontroller.h
//  Xcode Reader
//
//  Created by Song Hui 2013-4-11
//  Copyright(C)Song Hui. All rights reserved.

#import <UIKit/UIKit.h>

@interface SToolkitController : UIViewController<STabControlDelegate>

UIKIT_EXTERN NSUInteger kSToolkitControllerWidth;

//  Controller's root superview.
//  Be responsible for displaying a shadow effect at controller's right border.
@property (nonatomic, strong) UIView *containerView;

//  The superview for all children view controller.
@property (nonatomic, strong) UIView *viewControllerTransitionView;

//  SToolkitController's children view controller.
@property (nonatomic, strong) NSArray *viewControllers;

//  The current selected/ on screen child controller.
@property (nonatomic, strong) UIViewController *selectedViewController;

//  Self explained.
@property (nonatomic, assign) NSUInteger selectedIndex;

//  The main function bar of SToolkitController, controller use it to switch its children controllers.
//  ToolkitBar is a hybrid of UITabbar and Standard UIToolbar.
//  It has a STabControl to achieve the tab switch ability, along with that, it also has a setting button.
//  Because UIToolbar already can put STabControl and UIButton on itself, toolkitBar will be UIToolbar for now.
//  Subclass of UIToolbar may be required in later progress of Xcode Reader Project.
@property (nonatomic, strong) UIToolbar *toolkitBar;

//  Tab control located on toolkitBar. Controller use it to switch its children controllers.
@property (nonatomic, strong) STabControl *tabControl;

//  Toolkit Bar items will determine what's currently displayed on Toolkit Bar.
@property (nonatomic, strong) NSArray *barItems;

//  The root/ default Toolkit bar items.
@property (nonatomic, strong) NSArray *defautBarItems;

- (id)initWithViewControllers:(NSArray *)viewControllers selectedIndex:(NSUInteger)selectedIndex;

@end

@interface UIViewController (SToolkitController)

//  If view controller has a SToolkitController as its ancestor, return it. Otherwise, return nil.
//  Child view controller of SToolkitController that want to quick access SToolkitController can write an getter method in its implementation.
@property (nonatomic, readonly, weak) UIViewController *toolkitController;

//  Child view controller of SToolkitController can override this property's setter method in order to change the Bar items display on its parent' Toolkit Bar.
//  The override of setter method only require assign the SToolkitBarItems intended to be displayed on ToolkitBar, SToolkitController will notice the change and update the bar appropriately.
//  NOTICE: If not being a child of SToolkitController, don't implement this property.
@property (nonatomic, readwrite, weak) NSArray *toolkitBarItems;

@end

SToolkitController.m

//
//  SToolkitcontroller.m
//  Xcode Reader
//
//  Created by Song Hui 2013-4-11
//  Copyright(C)Song Hui. All rights reserved.

#import "SToolkitController.h"

const NSUInteger kSToolkitControllerWidth = 320;
const NSUInteger kSToolkitBarHeight = 44;
const UIEdgeInsets kSToolkitBarBackgroundImageCapInsets = UIEdgeInsetsZero; //Placeholder Value
const UIEdgeInsets kSToolkitBarShadowImageCapInsets = UIEdgeInsetsZero; //Placeholder Value
const UIEdgeInsets kSToolkitBarButtonBackgroundImageCapInsets = UIEdgeInsetsZero; //Placeholder Value
const CGRect kTabControlFrame = CGRectMake(40, 0, 180, 44);
const CGRect kSettingButtonFrame = CGRectMake(0, 0, 0, 0); //Placeholder Value
const NSString *kSToolkitBarBackgroundImageName = @"ToolkitBar-Background.png";
const NSString *kSToolkitBarShadowImageName = @"ToolkitBar-Shadow.png";
const NSString *kSTabControlSearchImageName = @"STabControl-Search.png";
const NSString *kSTabControlSearchSelectedImageName = @"STabControl-Search-Selected.png";
const NSString *kSTabControlExploreImageName = @"STabControl-Explore.png";
const NSString *kSTabControlExploreSelectedImageName = @"STabControl-Explore-Selected.png";
const NSString *kSTabControlBookmarkImageName = @"STabControl-Bookmark.png";
const NSString *kSTabControlBookmarkSelectedImageName = @"STabControl-Bookmark-Selected.png";
const NSString *kSToolkitBarButtonImageName = @"ToolkitBar-Button.png";
const NSString *kSToolkitBarButtonBackgroundImageName = @"ToolkitBar-Button-Background.png"
const NSString *kSToolkitBarButtonBackgroundSelectedImageName = @"ToolkitBar-Button-BackgroundSelected.png"

typedef NS_ENUM(NSInteger, SToolkitTransitionAnimation) {
    SToolkitTransitionAnimationNone,
    SToolkitTransitionAnimationPlaceholder1,
    SToolkitTransitionAnimationPlaceholder2
};

@interface SToolkitController : UIViewController()

//  Child view controller's transition will be added to this queue. And execute FIFO.
@property (nonatomic, strong) NSArray *transitionQueue;

@end

@implementation SToolkitController

#pragma mark - Life Cycle

- (id)initWithViewControllers:(NSArray *)viewControllers selectedIndex:(NSUInteger)selectedIndex
{
    self = [super init];
    if (self) {
        _viewControllers = viewControllers;
        _selectedIndex = selectedIndex;
        _transitionQueue = [[NSMutableArray alloc] init];

        //  Default Bar Items Creation
        UIImage *tabControlSearchImage = [UIImage imageNamed:kSTabControlSearchImageName];
        UIImage *tabControlExploreImage = [UIImage imageNamed:kSTabControlExploreImageName];
        UIImage *tabControlBookmarkImage = [UIImage imageNamed:kSTabControlBookmarkImageName];
        UIImage *tabControlSearchSelectedImage = [UIImage imageNamed:kSTabControlSearchSelectedImageName];
        UIImage *tabControlExploreSelectedImage = [UIImage imageNamed:kSTabControlExploreSelectedImageName];
        UIImage *tabControlBookmarkSelectedImage = [UIImage imageNamed:kSTabControlBookmarkSelectedImageName];
        STabControl *tabControl = [[STabControl alloc] initWithFrame:kTabControlFrame tabImages:@[tabControlSearchImage, tabControlExploreImage, tabControlBookmarkImage] tabSelectedImages:@[tabControlSearchSelectedImage, tabControlExploreSelectedImage, tabControlBookmarkSelectedImage]];
        tabControl.delegate = self;
        UIButton *settingButton = [[UIButton alloc] initWithFrame:kSettingButtonFrame];
        UIImage *settingButtonImage = [UIImage imageNamed:kSToolkitBarButtonImageName];
        UIImage *settingButtonBackgroundImage = [[UIImage imageNamed:kSToolkitBarButtonBackgroundImageName] resizableImageWithCapInsets:kSToolkitBarButtonBackgroundImageCapInsets];
        UIImage *settingButtonBackgroundSelectedImage = [[UIImage imageNamed:kSToolkitBarButtonBackgroundSelectedImageName] resizableImageWithCapInsets:kSToolkitBarButtonBackgroundImageCapInsets];
        [settingButton setImage:settingButtonImage forState:UIControlStateNormal];
        [settingButton setBackgroundImage:settingButtonBackgroundImage forState:UIControlStateNormal];
        [settingButton setBackgroundImage:settingButtonBackgroundSelectedImage forState:UIControlStateHighlighted | UIControlStateSelected];
        [settingButton addTarget:self action:@selector(settingButtonTouchUpInside:) forControlEvent:UIControlEventTouchUpInside];
        NSArray *defaultBarItems = @[tabControl, settingButton];
        _defaultBarItems = defaultBarItems;
        _barItems = defaultBarItems;
    }
    return self;
}

- (void)loadView
{
    CGSize applicationSize = [[UIScreen mainScreen] applicationFrame].size;
    CGFloat applicationHeight = applicationSize.height;
    if (UIInterfaceOrientationIsLandscape(self.interfaceOrientation)) {
        applicationHeight = applicationSize.width;
    }

    //  Alloc and init views
    _containerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, kSToolkitControllerWidth, applicationHeight)];
    _viewControllerTransitionView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, kSToolkitControllerWidth, applicationHeight - kSToolkitBarHeight)];
    UIImage *toolkitBarBackgroundImage = [[UIImage imageNamed:kSToolkitBarBackgroundImageName] resizableImageWithCapInsets:kSToolkitBarBackgroundImageCapInsets];
    UIImage *toolkitBarShadowImage = [[UIImage imageNamed:kSToolkitBarShadowImageName] resizableImageWithCapInsets:kSToolkitBarShadowImageCapInsets];
    _toolkitBar = [[SToolkitBar alloc] initWithFrame:CGRectMake(0, applicationHeight - kSToolkitBarHeight, kSToolkitControllerWidth, kSToolkitBarHeight) barItems:self.barItems backgroundImage:toolkitBarBackgroundImage shadowImage:toolkitBarShadowImage];
    
    //  Views's autoresizingMask configuration.
    _containerView.autoresizingMask = UIViewAutoresizingMaskFlexibleHeight | UIViewAutoresizingMaskFlexibleRightMargin | UIViewAutoresizingMaskFlexibleBottomMargin;
    _viewControllerTransitionView.autoresizingMask = UIViewAutoresizingMaskFlexibleHeight | UIViewAutoresizingMaskFlexibleRightMargin | UIViewAutoresizingMaskFlexibleBottomMargin;
    _toolkitBar.autoresizingMask = UIViewAutoresizingMaskFlexibleTopMargin | UIViewAutoresizingMaskFlexibleRightMargin;

    //  Add Subviews
    self.view = _containerView;
    [_containerView addSubview:_viewControllerTransitionView];
    [_containerView addSubView:_toolkitBar];
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Children view controllers' toolkitBatItem observing.
    for (UIViewController *viewController in self.viewController) {
        [viewController addObserver:self forKeyPath:@"toolkitBatItems" options:NSKeyValueObservingNew context:nil];
    }
}

#pragma mark - Children View Controllers Management and Transition

- (void)selectViewControllerAtIndex:(NSUInteger)selectedIndex animationType:(SToolkitTransitionAnimation)animationType
{
    if (!self.selectedViewController || self.selectedIndex != selectedIndex) {
        NSArray *transition = @[@self.selectedIndex, @selectedIndex];
        //  Add transition to transition queue.
        if (self.transitionQueue.count == 0) {
            [self.transitionQueue addObject:transition];
            //  Only immediately start transition if queue is empty.
            [self executeTransitionWithAnimationType:animationType];
        }   else {
            [self.transitionQueue addObject:transition];
        }
    }
}

- (void)executeTransitionWithAnimationType:(SToolkitTransitionAnimation)animationType
{
    NSArray *transition = self.transitionQueue[0];
    NSUInteger fromIndex = [transition[0] integerValue];
    NSUInteger toIndex = [transition[1] integerValue];
    UIViewController *fromController = self.viewControllers[fromIndex];
    UIViewController *toController = self.viewControllers[toIndex];
    if (animationType == SToolkitTransitionAnimationNone) {
        toController.view.frame = CGRectMake(0, 0, self.viewControllerTransitionView.bounds.size.width, self.viewControllerTransitionView.bounds.size.height);
        if (self.selectedViewController && self.selectedViewController == fromController) {
            [self.selectedViewController removeFromParentViewController];
            [self.selectedViewController beginAppearanceTransition:NO animated:NO];
            [self.selectedViewController.view removeFromSuperview];
            [self.selectedViewController endAppearanceTransition];
        }
        [self addChildViewController:toController];
        [toController beginAppearanceTransition:YES animated:NO];
        [self.viewControllerTransitionView addSubview:toController.view];
        [toController endAppearanceTransition];
    }   else if (animationType == SToolkitTransitionAnimationPlaceHolder1) {
    }
    self.selectedIndex = toIndex;
    self.selectedViewController = toController;
    
    //  Queue out transition and execute next one if there is.
    [self.transitionQueue removeObject:transition];
    if (self.transitionQueue.count != 0) {
        [self executeTransitionWithAnimationType:SToolkitTransitionAnimationNone];
    }
}

- (void)tabControl:(STabControl *)tabControl didSelectTabAtIndex:(NSUInteger)index
{
    [self selectViewControllerAtIndex:index animationType:SToolkitTransitionAnimationNone];
}

#pragma mark - Toolkit Bar Items Update

- (void)observeForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([keyPath isEqualToString:@"toolkitBarItems"] && object == self.selectedViewController) {
        self.barItems = self.selectedViewController.toolkitBarItems;
        self.tookitBar.barItems = self.barItems;
    }
}

@end