////  RootViewController.m//  ColorLabels////  Copyright (c) 2014年 Y.X. All rights reserved.//#import "RootViewController.h"#import "YXGCD.h"@interface RootViewController ()@property (nonatomic, strong)  UIView   *upView;@property (nonatomic, strong)  UILabel  *upLabel;@property (nonatomic, strong)  UIView   *downView;@property (nonatomic, strong)  UILabel  *downLabel;@property (nonatomic, strong)  GCDTimer *timer;@end@implementation RootViewController- (void)viewDidLoad{    [super viewDidLoad];        /*
     给upView的frame值做动画才是label能够混色显示的核心               upView(红色背景)   ===>  upLabel(白色底字)           |                       |           |                       |           |                       |           |                       |     downView(白色背景) ===> downLabel(红色底字)          */        // 上面一层    {        // 红色背景        _upView                     = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 15)];        _upView.center              = self.view.center;        _upView.layer.cornerRadius  = 2.f;        _upView.backgroundColor     = [UIColor redColor];        _upView.layer.masksToBounds = YES; // 核心(不让subview显示超出范围)        [self.view addSubview:_upView];                // 白色底字        _upLabel                    = [[UILabel alloc] initWithFrame:_upView.bounds];        _upLabel.font               = [UIFont fontWithName:@"HelveticaNeue-Thin" size:10.f];        _upLabel.text               = @"You Xian Ming No Zuo No Die";        _upLabel.textColor          = [UIColor whiteColor];        _upLabel.textAlignment      = NSTextAlignmentCenter;        [_upView addSubview:_upLabel];    }        // 下面一层    {        // 白色背景        _downView                     = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 15)];        _downView.center              = self.view.center;        _downView.layer.cornerRadius  = 2.f;        _downView.backgroundColor     = [UIColor whiteColor];        [self.view addSubview:_downView];                // 红色底字        _downLabel                    = [[UILabel alloc] initWithFrame:_downView.bounds];        _downLabel.textColor          = [UIColor redColor];        _downLabel.font               = [UIFont fontWithName:@"HelveticaNeue-Thin" size:10.f];        _downLabel.text               = @"You Xian Ming No Zuo No Die";        _downLabel.textAlignment = NSTextAlignmentCenter;        [_downView addSubview:_downLabel];    }        // 显示上面一层    [self.view bringSubviewToFront:_upView];        // 给上面一层的frame值做动画    _timer = [[GCDTimer alloc] initInQueue:[GCDQueue mainQueue]];    [_timer event:^{                [UIView animateWithDuration:0.3f animations:^{            CGRect tmpRect = _upView.frame;            tmpRect.size.width = arc4random()%200;            _upView.frame = tmpRect;        }];            } timeInterval:NSEC_PER_SEC];    [_timer start];}@end