CarbonTabSwipeSegmentedControl.m

//  The MIT License (MIT)
//
//  Copyright (c) 2015 - present Ermal Kaleci
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.
//

#import "CarbonTabSwipeSegmentedControl.h"


@interface CarbonTabSwipeSegmentedControl ()
@end

@implementation CarbonTabSwipeSegmentedControl

- (instancetype)initWithItems:(NSArray *)items {
    self = [super initWithItems:items];
    if (self) {

        self.indicatorHeight = 3;
        self.selectedSegmentIndex = 0;
        self.apportionsSegmentWidthsByContent = YES;

        // Create indicator
        self.indicator = [UIImageView new];
        self.indicator.backgroundColor = self.tintColor;
        self.indicator.autoresizingMask = UIViewAutoresizingNone;
        [self addSubview:self.indicator];

        // Custimize segmented control
        id titleAttr = @{
            NSForegroundColorAttributeName : [self.tintColor colorWithAlphaComponent:0.8],
            NSFontAttributeName : [UIFont boldSystemFontOfSize:14]
        };
        [self setTitleTextAttributes:titleAttr forState:UIControlStateNormal];

        id selectedTittleAttr = @{
            NSForegroundColorAttributeName : self.tintColor,
            NSFontAttributeName : [UIFont boldSystemFontOfSize:14]
        };
        [self setTitleTextAttributes:selectedTittleAttr forState:UIControlStateSelected];

        // Disable tint color and divider image
        [self setTintColor:[UIColor clearColor]];
        [self setDividerImage:[UIImage new]
            forLeftSegmentState:UIControlStateNormal
              rightSegmentState:UIControlStateNormal
                     barMetrics:UIBarMetricsDefault];

        [self setClipsToBounds:FALSE];
        [self setBackgroundImage:[UIImage new]
                        forState:UIControlStateNormal
                      barMetrics:UIBarMetricsDefault];
        [self setBackgroundImage:[UIImage new]
                        forState:UIControlStateSelected
                      barMetrics:UIBarMetricsDefault];

        // Fix indicator frame
        if (items) {
            self.indicatorMinX = [self getMinXForSegmentAtIndex:self.selectedSegmentIndex];
            self.indicatorWidth = [self getWidthForSegmentAtIndex:self.selectedSegmentIndex];
            [self updateIndicatorWithAnimation:NO];
        }

        [self addTarget:self
                      action:@selector(segmentedTapped:)
            forControlEvents:UIControlEventValueChanged];
    }
    return self;
}

- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];

    // Add extra width to each segment and calculate the segment width
    CGFloat totalWidth = 0;
    for (UIView *segment in self.segments) {
        NSInteger index = [self.segments indexOfObject:segment];
        CGFloat width = [self getWidthForSegmentAtIndex:index];
        CGRect segmentRect = segment.frame;
        segmentRect.origin.x = totalWidth;
        segmentRect.size.width = width + _tabExtraWidth;
        segment.frame = segmentRect;
        totalWidth += segmentRect.size.width;
    }

    _tabExtraWidth = 0;

    // Set the width of UISegmentedControl to fit all segments
    rect.size.width = totalWidth;
    self.frame = rect;

    // Change images tint
    [self syncImageTintColor];

    // Sync indicator
    dispatch_async(dispatch_get_main_queue(), ^{
        self.indicatorMinX = [self getMinXForSegmentAtIndex:self.selectedSegmentIndex];
        self.indicatorWidth = [self getWidthForSegmentAtIndex:self.selectedSegmentIndex];
        [self updateIndicatorWithAnimation:NO];
    });
}

- (void)didChangeValueForKey:(NSString *)key {
    if ([key isEqualToString:@"selectedSegmentIndex"]) {
        [self syncImageTintColor];
    }
}

- (void)setTabExtraWidth:(CGFloat)tabExtraWidth {
    _tabExtraWidth = tabExtraWidth;

    [self setNeedsDisplay];
}

- (void)setTitleTextAttributes:(NSDictionary *)attributes forState:(UIControlState)state {
    [super setTitleTextAttributes:attributes forState:state];

    if (state == UIControlStateNormal) {
        [self setImageNormalColor:attributes[NSForegroundColorAttributeName]];
    } else if (state == UIControlStateSelected) {
        [self setImageSelectedColor:attributes[NSForegroundColorAttributeName]];
    }
}

- (void)setSelectedSegmentIndex:(NSInteger)selectedSegmentIndex {
    [super setSelectedSegmentIndex:selectedSegmentIndex];
    [self syncImageTintColor];
}

- (void)setImageNormalColor:(UIColor *)normalColor {
    _imageNormalColor = normalColor;
    [self syncImageTintColor];
}

- (void)setImageSelectedColor:(UIColor *)selectedColor {
    _imageSelectedColor = selectedColor;
    [self syncImageTintColor];
}

- (void)syncImageTintColor {
    for (UIView *segment in self.segments) {
        for (UIView *subView in segment.subviews) {
            if ([subView isKindOfClass:[UIImageView class]]) {
                if ([self.segments indexOfObject:segment] == self.selectedSegmentIndex) {
                    subView.tintColor = _imageSelectedColor;
                } else {
                    subView.tintColor = _imageNormalColor;
                }
            }
        }
    }
}

#pragma mark - Properties

- (NSArray<UIView *> *)segments {
    return [self valueForKey:@"_segments"];
}

- (UIView *)getSelectedSegment {
    return self.segments[self.selectedSegmentIndex];
}

- (CGFloat)getMinXForSegmentAtIndex:(NSUInteger)index {
    return CGRectGetMinX(self.segments[index].frame);
}

- (CGFloat)getWidthForSegmentAtIndex:(NSUInteger)index {
    if (![self isRTL] && index == [self.segments count] - 1) {
        return CGRectGetWidth(self.frame) - CGRectGetMinX(self.segments[index].frame);
    }
    return CGRectGetWidth(self.segments[index].frame);
}

- (CGFloat)getWidth {
    CGFloat width = 0;
    for (UIView *segment in self.segments) {
        width += CGRectGetWidth(segment.frame);
    }
    return width;
}

#pragma mark - Actions

- (void)segmentedTapped:(id)sender {
    self.indicatorMinX = [self getMinXForSegmentAtIndex:self.selectedSegmentIndex];
    self.indicatorWidth = [self getWidthForSegmentAtIndex:self.selectedSegmentIndex];
    [self updateIndicatorWithAnimation:YES];
}

- (void)updateIndicatorWithAnimation:(BOOL)animation {
    CGFloat indicatorY = 0;

    if (self.indicatorPosition == IndicatorPositionBottom) {
        indicatorY = CGRectGetHeight(self.frame) - self.indicatorHeight;
    }

    [UIView animateWithDuration:animation ? 0.3 : 0
                     animations:^{
                         CGRect rect = self.indicator.frame;
                         rect.origin.x = self.indicatorMinX;
                         rect.origin.y = indicatorY;
                         rect.size.width = self.indicatorWidth;
                         rect.size.height = self.indicatorHeight;
                         self.indicator.frame = rect;
                     }];
}

- (BOOL)isRTL {
    if (@available(iOS 9.0, *)) {
        return [UIView userInterfaceLayoutDirectionForSemanticContentAttribute:self.semanticContentAttribute] == UIUserInterfaceLayoutDirectionRightToLeft;
    }
    return NO;
}

@end