BDSegmentedControl.h

#import <UIKit/UIKit.h>

@class BDSegmentedControl;

@protocol BDSegmentedControlDelegate <NSObject>

- (NSUInteger)segmentedControl:(BDSegmentedControl *)segmentedControl numberOfMenuItemsForSegmentAtIndex:(NSUInteger)segmentIndex;
- (UIImage *)segmentedControl:(BDSegmentedControl *)segmentedControl imageForMenuBackgroundForSegmentAtIndex:(NSUInteger)segmentIndex;
- (UIImage *)segmentedControl:(BDSegmentedControl *)segmentedControl imageForMenuItemAtIndex:(NSUInteger)menuItemIndex forSegmentAtIndex:(NSUInteger)segmentIndex;
- (UIImage *)segmentedControl:(BDSegmentedControl *)segmentedControl imageForSelectedMenuItemAtIndex:(NSUInteger)menuItemIndex forSegmentAtIndex:(NSUInteger)segmentIndex;
- (UIImage *)segmentedControl:(BDSegmentedControl *)segmentedControl imageForSelectedSegment:(NSUInteger)segmentIndex whenMenuItemAtIndexIsSelected:(NSUInteger)menuItemIndex;

@end

@interface BDSegmentedControl : UIControl

- (id)initWithSegments:(NSUInteger)numberOfSegments;

@property (nonatomic, readwrite, assign) id<BDSegmentedControlDelegate> delegate;

@property (nonatomic, readwrite, assign) NSUInteger numberOfSegments;
@property (nonatomic, readwrite, assign) NSUInteger selectedSegmentIndex;
@property (nonatomic, readwrite, assign) NSUInteger selectedMenuItem;

@property (nonatomic, readwrite, assign) CGFloat imageScale;

- (void)setImage:(UIImage *)image forSegmentAtIndex:(NSUInteger)segment;
- (void)setSelectedImage:(UIImage *)image forSegmentAtIndex:(NSUInteger)segment;

@end

BDSegmentedControl.m

#import "BDSegmentedControl.h"

@interface BDSegmentedControl ()

@property (nonatomic, readwrite, retain) NSArray *segmentButtons;
@property (nonatomic, readwrite, retain) NSArray *menuItems;
@property (nonatomic, readwrite, retain) NSMutableArray *selectedImages;
@property (nonatomic, readwrite, assign) BOOL menuOpen;

@property (nonatomic, readwrite, retain) UIView *menuView;

@property (nonatomic, readwrite, assign) CGRect normalFrame;

- (void)segmentTapped:(id)sender;
- (void)menuItemTapped:(id)sender;

- (void)openMenu;
- (void)closeMenuThen:(void(^)(void))completion;

@end

@implementation BDSegmentedControl
{
    NSUInteger numberOfSegments;
    NSUInteger selectedSegmentIndex;
    NSUInteger selectedMenuItem;
}

@synthesize delegate;

@synthesize segmentButtons;
@synthesize menuItems;
@synthesize selectedImages;
@synthesize imageScale;

@synthesize menuOpen;
@synthesize menuView;

@synthesize normalFrame;

- (id)initWithSegments:(NSUInteger)initNumberOfSegments
{
    self = [super init];
    
    if (nil != self)
    {
        [self setSelectedMenuItem:NSNotFound];
        [self setSegmentButtons:[NSArray array]];
        [self setSelectedImages:[NSMutableArray array]];
        [self setImageScale:1.0];
        [self setNumberOfSegments:initNumberOfSegments];
        [self setBackgroundColor:[UIColor clearColor]];
        [self setNormalFrame:[self frame]];
    }
    
    return self;
}

- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    
    if (nil != self)
    {
        [self setSelectedMenuItem:NSNotFound];
        [self setSegmentButtons:[NSArray array]];
        [self setSelectedImages:[NSMutableArray array]];
        [self setImageScale:1.0];
        [self setNumberOfSegments:1];
        [self setBackgroundColor:[UIColor clearColor]];
        [self setNormalFrame:[self frame]];
    }
    
    return self;
}

- (id)init
{
    return [self initWithSegments:1];
}

- (void)dealloc
{
    [self setSegmentButtons:nil];
    [self setMenuItems:nil];
    [self setSelectedImages:nil];
    [self setMenuView:nil];
    
    [super dealloc];
}

- (NSUInteger)numberOfSegments
{
    return numberOfSegments;
}

- (void)setNumberOfSegments:(NSUInteger)newNumberOfSegments
{
    if (numberOfSegments != newNumberOfSegments)
    {
        if (newNumberOfSegments < numberOfSegments)
        {
            [self setSegmentButtons:[[self segmentButtons] subarrayWithRange:NSMakeRange(0, newNumberOfSegments)]];
            [self setSelectedImages:[[[[self selectedImages] subarrayWithRange:NSMakeRange(0, newNumberOfSegments)] mutableCopy] autorelease]];
        }
        else
        {
            NSMutableArray *newSegmentButtons = [[[self segmentButtons] mutableCopy] autorelease];
            for (NSUInteger i = numberOfSegments; i < newNumberOfSegments; i++)
            {
                UIButton *b = [UIButton buttonWithType:UIButtonTypeCustom];
                [b setAdjustsImageWhenDisabled:NO];
                [b setAdjustsImageWhenHighlighted:NO];
                [b setShowsTouchWhenHighlighted:NO];
                [b addTarget:self action:@selector(segmentTapped:) forControlEvents:UIControlEventTouchUpInside];
                [b setSelected:i == [self selectedSegmentIndex]];
                [newSegmentButtons addObject:b];
                [self addSubview:b];
                
                [[self selectedImages] addObject:[NSNull null]];
            }
            [self setSegmentButtons:newSegmentButtons];
        }
        numberOfSegments = newNumberOfSegments;
        [self setNeedsLayout];
    }
}

- (NSUInteger)selectedSegmentIndex
{
    return selectedSegmentIndex;
}

- (void)setSelectedSegmentIndex:(NSUInteger)newSelectedSegmentIndex
{
    if (selectedSegmentIndex != newSelectedSegmentIndex)
    {
        id img = [[self selectedImages] objectAtIndex:selectedSegmentIndex];
        if ([img isKindOfClass:[UIImage class]])
        {
            [[[self segmentButtons] objectAtIndex:selectedSegmentIndex] setImage:img forState:UIControlStateSelected];
        }
        [[[self segmentButtons] objectAtIndex:selectedSegmentIndex] setSelected:NO];
        [[[self segmentButtons] objectAtIndex:newSelectedSegmentIndex] setSelected:YES];
        selectedSegmentIndex = newSelectedSegmentIndex;
        
        [self setSelectedMenuItem:NSNotFound];
    }
}

- (NSUInteger)selectedMenuItem
{
    return selectedMenuItem;
}

- (void)setSelectedMenuItem:(NSUInteger)newSelectedMenuItem
{
    if (selectedMenuItem != newSelectedMenuItem)
    {
        if (NSNotFound == newSelectedMenuItem)
        {
            [[[self segmentButtons] objectAtIndex:[self selectedSegmentIndex]] setImage:[[self selectedImages] objectAtIndex:[self selectedSegmentIndex]] forState:UIControlStateSelected];
        }
        else
        {
            [[[self segmentButtons] objectAtIndex:[self selectedSegmentIndex]] setImage:[[self delegate] segmentedControl:self imageForSelectedSegment:[self selectedSegmentIndex] whenMenuItemAtIndexIsSelected:newSelectedMenuItem]
                                                                               forState:UIControlStateSelected];
        }
        selectedMenuItem = newSelectedMenuItem;
    }
}

- (void)segmentTapped:(id)sender
{
    NSUInteger newSelectedSegmentIndex = [[self segmentButtons] indexOfObject:sender];
    if (newSelectedSegmentIndex != [self selectedSegmentIndex])
    {
        [self closeMenuThen:^()
         {
             [self setSelectedSegmentIndex:newSelectedSegmentIndex];
             if (0 != [[self delegate] segmentedControl:self numberOfMenuItemsForSegmentAtIndex:newSelectedSegmentIndex])
             {
                 [self openMenu];
             }
             else
             {
                 [self sendActionsForControlEvents:UIControlEventValueChanged];
             }
         }];
    }
    else if (![self menuOpen])
    {
        if (0 != [[self delegate] segmentedControl:self numberOfMenuItemsForSegmentAtIndex:newSelectedSegmentIndex])
        {
            [self openMenu];
        }
    }
}

- (void)menuItemTapped:(id)sender
{
    NSUInteger newSelectedMenuItemIndex = [[self menuItems] indexOfObject:sender];
    if (newSelectedMenuItemIndex != [self selectedMenuItem])
    {
        [self closeMenuThen:^()
         {
             [self setSelectedMenuItem:newSelectedMenuItemIndex];
             [self sendActionsForControlEvents:UIControlEventValueChanged];
         }];
    }
}

#define kButtonFadeLength 0.1

- (void)openMenu
{
    [self setNormalFrame:[self frame]];
    UIButton *b = [[self segmentButtons] objectAtIndex:[self selectedSegmentIndex]];
    CGRect bFrame = [b frame];
    [self setMenuView:[[[UIView alloc] initWithFrame:CGRectMake(bFrame.origin.x, bFrame.origin.y + bFrame.size.height - 5.0f, bFrame.size.width, 0.0f)] autorelease]];
    [[self menuView] setOpaque:NO];
    [[self menuView] setBackgroundColor:[UIColor clearColor]];
        
    [self insertSubview:[self menuView] belowSubview:b];
    
    NSUInteger numberOfItems = [[self delegate] segmentedControl:self numberOfMenuItemsForSegmentAtIndex:[self selectedSegmentIndex]];
    CGFloat buttonFadePeriod = 0.3 - kButtonFadeLength;
    CGFloat buttonFadeOffset = buttonFadePeriod / (numberOfItems + 1);
    CGFloat buttonFadeStart = buttonFadeOffset;
    CGFloat buttonTop = 0.0f;
    CGFloat buttonWidth = [b bounds].size.width;
    NSMutableArray *newMenuItems = [NSMutableArray arrayWithCapacity:numberOfItems];
    for (NSUInteger i = 0; i < numberOfItems; i++)
    {
        UIImage *buttonImage = [[self delegate] segmentedControl:self imageForMenuItemAtIndex:i forSegmentAtIndex:[self selectedSegmentIndex]];
        CGFloat buttonHeight = [buttonImage size].height;
        UIButton *menuItem = [[[UIButton alloc] initWithFrame:CGRectMake(0.0, buttonTop, buttonWidth, buttonHeight)] autorelease];
        [menuItem setImage:buttonImage forState:UIControlStateNormal];
        [menuItem setImage:[[self delegate] segmentedControl:self imageForSelectedMenuItemAtIndex:i forSegmentAtIndex:[self selectedSegmentIndex]] forState:UIControlStateSelected];
        [menuItem addTarget:self action:@selector(menuItemTapped:) forControlEvents:UIControlEventTouchUpInside];
        [menuItem setOpaque:NO];
        [menuItem setAlpha:0.0];
        [[self menuView] addSubview:menuItem];
        [newMenuItems addObject:menuItem];
        
        [UIView animateWithDuration:0.3
                              delay:buttonFadeStart
                            options:UIViewAnimationCurveLinear
                         animations:^()
         {
             [menuItem setAlpha:1.0];
         }
                         completion:^(BOOL finished) {}];
        
        buttonFadeStart += buttonFadeOffset;
        buttonTop += buttonHeight;
    }
    [self setMenuItems:newMenuItems];
    
    [UIView animateWithDuration:0.3
                     animations:^()
     {
         [[self menuView] setFrame:CGRectMake(bFrame.origin.x, bFrame.origin.y + bFrame.size.height - 5.0, bFrame.size.width, buttonTop)];
     }];
    
    [self setMenuOpen:YES];
    
    [self setFrame:CGRectMake([self frame].origin.x, [self frame].origin.y, [self frame].size.width, [self frame].size.height + buttonTop)];
}

- (void)closeMenuThen:(void(^)(void))completion
{
    [self setFrame:[self normalFrame]];
    UIButton *b = [[self segmentButtons] objectAtIndex:[self selectedSegmentIndex]];
    CGRect bFrame = [b frame];
    
    NSUInteger numberOfItems = [[self delegate] segmentedControl:self numberOfMenuItemsForSegmentAtIndex:[self selectedSegmentIndex]];
    CGFloat buttonFadePeriod = 0.3 - kButtonFadeLength;
    CGFloat buttonFadeOffset = buttonFadePeriod / (numberOfItems + 1);
    CGFloat buttonFadeStart = buttonFadeOffset;
    for (NSInteger i = numberOfItems - 1; i >= 0; i--)
    {
        [UIView animateWithDuration:0.3
                              delay:buttonFadeStart
                            options:UIViewAnimationCurveLinear
                         animations:^()
         {
             [[[self menuItems] objectAtIndex:i] setAlpha:0.0];
         }
                         completion:^(BOOL finished) {}];
        buttonFadeStart += buttonFadeOffset;
    }
    
    [UIView animateWithDuration:0.3
                     animations:^()
     {
         [[self menuView] setFrame:CGRectMake(bFrame.origin.x, bFrame.origin.y + bFrame.size.height - 5.0, bFrame.size.width, 0.0)];
     }
                     completion:^ (BOOL finished)
     {
         [self setMenuItems:nil];
         [[self menuView] removeFromSuperview];
         [self setMenuView:nil];
         [self setMenuOpen:NO];
         completion();
     }];
}

- (void)setImage:(UIImage *)image forSegmentAtIndex:(NSUInteger)segment
{
    UIButton *b = [[self segmentButtons] objectAtIndex:segment];
    [b setImage:image forState:UIControlStateNormal];
    [self setNeedsLayout];
}

- (void)setSelectedImage:(UIImage *)image forSegmentAtIndex:(NSUInteger)segment
{
    UIButton *b = [[self segmentButtons] objectAtIndex:segment];
    [b setImage:image forState:UIControlStateSelected];
    [[self selectedImages] replaceObjectAtIndex:segment withObject:image];
    [self setNeedsLayout];
}

- (void)layoutSubviews
{
    CGFloat o = [self bounds].origin.x;
    CGFloat y = [self bounds].origin.y;

    for (UIButton *button in [self segmentButtons])
    {
        UIImage *buttonImage = [button imageForState:UIControlStateNormal];
        CGFloat bw = [buttonImage size].width / [self imageScale];
        [button setFrame:CGRectMake(o, y, bw, [buttonImage size].height / [self imageScale])];
        o += bw;
    }
}

@end