在一个Label上设置多种颜色字体

 #import "AppDelegate.h"

 @interface AppDelegate ()

 @end

 @implementation AppDelegate

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
     self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

     // Override point for customization after application launch.
     self.window.backgroundColor = [UIColor whiteColor];

     UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(, , , )];
     // 设置多属性字符串
     NSMutableAttributedString *str = [[NSMutableAttributedString alloc] initWithString:@"Using   NSAttributed   String"];
     // 设置蓝色字体，范围(0, 5)，其中空格也算一个占位符
     [str addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(, )];
     // 设置红色字体，范围(6, 12)，其中空格也算一个占位符
     [str addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(, )];
     // 设置红色字体，范围(13, 6)，其中空格也算一个占位符
     [str addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:NSMakeRange(, )];

     label.attributedText = str;

     [self.window addSubview:label];
     [self.window makeKeyAndVisible];
     return YES;
 }

 @end