在黑色UISegmentedControl上更改选定的段背景颜色

Question

我正在使用最新的SDK和Xcode 4.2开发iOS 4应用程序。

我在AppDelegate上以编程方式添加了UINavigationController，并将其设置为黑色。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    viewController.title = @"Menu";
    navController = [[UINavigationController alloc] initWithRootViewController:viewController];
    navController.navigationBar.tintColor = [UIColor blackColor];

    self.window.rootViewController = navController;

    [self.window makeKeyAndVisible];
    return YES;
}

在一个视图控制器上，我添加了一个UISegmentedControl：

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.


    // Do any additional setup after loading the view from its nib.
    segmentedControl = [[UISegmentedControl alloc] initWithItems:
                                            [NSArray arrayWithObjects:
                                             [NSString stringWithString:@"Past"],
                                             [NSString stringWithString:@"Present"],
                                             [NSString stringWithString:@"Future"],
                                             nil]];

    [segmentedControl addTarget:self action:@selector(segmentedChanged:) forControlEvents:UIControlEventValueChanged];
    segmentedControl.frame = CGRectMake(0, 0, 260, 30);
    segmentedControl.segmentedControlStyle = UISegmentedControlStyleBar;
    segmentedControl.selectedSegmentIndex = 0;

    self.navigationItem.titleView = segmentedControl;
}

但是，当我选择一个项目时，我可以看到它，因为它是黑色的。

当选择某个项目时，是否还要设置为其他颜色？

Answer 1

尝试使用segmentedControlIndexChanged，然后使用self.segmentedControl.selectedSegmentIndex检测选择了哪一个并更改了这些段颜色。