UISegmentedControlのボタンの色を任意に変える

下記の例では「Month」と「All」、「Timeline」と「Tag」をそれぞれ排他的に選択させたいが、UISegmentedControlでは複数のグループには分割できない。それぞれのボタンに色をつけることでそれを擬似的に表現したい。

初期状態では「Month」「Timeline」がそれぞれ選択されている。

「All」をタッチすると、「Month」の色が消えて、「All」に色がつく。「Timeline」と「Tag」に変化はない。

さらに「Tag」をタッチすると、同様にボタンの色が変化する。

以下、コード。

- (void)viewWillAppear:(BOOL)animated {
	
    navigationSegment = [[UISegmentedControl alloc] initWithItems:nil];
    navigationSegment.segmentedControlStyle = UISegmentedControlStyleBar;
    navigationSegment.momentary = YES;
    
    //initialize UISegmentedControl
    //UISegmentedControlの初期化
    [navigationSegment insertSegmentWithTitle:NSLocalizedString(@"month", @"Month")  atIndex:0 animated:NO];
    [navigationSegment insertSegmentWithTitle:NSLocalizedString(@"all", @"All")  atIndex:1 animated:NO];
    [navigationSegment insertSegmentWithTitle:NSLocalizedString(@"sorttime",@"Timeline")  atIndex:2 animated:NO];
    [navigationSegment insertSegmentWithTitle:NSLocalizedString(@"sorttag",@"Tag")  atIndex:3 animated:NO];
    [navigationSegment insertSegmentWithImage:[UIImage imageNamed: @"mail2.png"] atIndex:4 animated:NO];
    
    //call controlPressed when UISegmentedControl is pushed
    //UISegmentedControlが押されたら、controlPressedメソッドを呼ぶ
    [navigationSegment addTarget:self action:@selector(controlPressed:) forControlEvents:UIControlEventValueChanged];

    //Initial value: Month and Timeline is ON.
    //初期値はMonthがON,TimelineがON
    tagOrTime = TIMELINE_FLAG_ON;
    allOrMonth = MONTH_FLAG_ON;
    
    //When view is displayed, objectAtIndex(es) are 0, 1, 2, 3, and 4 from the left.
    //viewが表示されたときは、objectAtIndexは左から0,1,2,3,4。
    [[[navigationSegment subviews] objectAtIndex:0] setTintColor:[UIColor colorWithRed: 0/255.0 green:32/255.0 blue:128/255.0 alpha:0.2]];
    [[[navigationSegment subviews] objectAtIndex:1] setTintColor:nil];
    [[[navigationSegment subviews] objectAtIndex:2] setTintColor:[UIColor colorWithRed: 0/255.0 green:32/255.0 blue:128/255.0 alpha:0.2]];
    [[[navigationSegment subviews] objectAtIndex:3] setTintColor:nil];

    
    
}


- (void)controlPressed:(id)sender{
    int index = navigationSegment.selectedSegmentIndex;
    
    if(index == 2){
        tagOrTime = TIMELINE_FLAG_ON;
    }else if(index == 3){
        tagOrTime = TAG_FLAG_ON;
    }else if(index == 0){
        allOrMonth = MONTH_FLAG_ON;
    }else if(index == 1){
        allOrMonth = ALL_FLAG_ON;
    }else if(index == 4){
    	....
    }
    
    //Since the turn of Subview of UISegmentedControl changes irregularly, it rearranges from the left.
    //UISegmentedControlのSubviewの順番がなぜかコロコロ変わってしまうので、左から並び替える。
    NSArray *sortedViews = [navigationSegment.subviews sortedArrayUsingFunction:compareViewsByOrigin context:NULL];

    //A flag is changed according to the button pushed now.
    //現在押されているボタンに従って、フラグを変更する。
    if (tagOrTime == TAG_FLAG_ON) {
        [[sortedViews  objectAtIndex:2] setTintColor:nil];
        [[sortedViews  objectAtIndex:3] setTintColor:[UIColor colorWithRed: 0/255.0 green:32/255.0 blue:128/255.0 alpha:0.2]];
    } else {
        [[sortedViews objectAtIndex:3] setTintColor:nil];
        [[sortedViews objectAtIndex:2] setTintColor:[UIColor colorWithRed: 0/255.0 green:32/255.0 blue:128/255.0 alpha:0.2]];
        
    }
    
    if (allOrMonth == ALL_FLAG_ON) {
        [[sortedViews objectAtIndex:0] setTintColor:nil];
        [[sortedViews objectAtIndex:1] setTintColor:[UIColor colorWithRed: 0/255.0 green:32/255.0 blue:128/255.0 alpha:0.2]];
    } else {
        [[sortedViews objectAtIndex:1] setTintColor:nil];
        [[sortedViews objectAtIndex:0] setTintColor:[UIColor colorWithRed: 0/255.0 green:32/255.0 blue:128/255.0 alpha:0.2]];
    }

    // Remove all original segments from the control
    // 一旦Subviewをすべて削除
    for (id view in navigationSegment.subviews) {
        [view removeFromSuperview];
    }
    
    // Append sorted and colored segments to the control
    //　色を変えたsubviewを付け替える
    for (id view in sortedViews) {
        [navigationSegment addSubview:view];
    }

}
         
//subviews sort function
//ソート関数
NSInteger static compareViewsByOrigin(id sp1, id sp2, void *context)
{
    // UISegmentedControl segments use UISegment objects (private API). But we can safely cast them to UIView objects.
    float v1 = ((UIView *)sp1).frame.origin.x;
    float v2 = ((UIView *)sp2).frame.origin.x;
    if (v1 < v2)
        return NSOrderedAscending;
    else if (v1 > v2)
        return NSOrderedDescending;
    else
        return NSOrderedSame;
}

Thank you, https://goddess-gate.com/dc2/index.php/post/454