UILabel混色顯示

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UILabel混色顯示

 

效果:

源碼:

////  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];        /*
     給upView的frame值做動畫才是label能夠混色顯示的核心               upView(紅色背景)   ===>  upLabel(白色底字)           |                       |           |                       |           |                       |           |                       |     downView(白色背景) ===> downLabel(紅色底字)          */        // 上面一層    {        // 紅色背景        _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(不讓subview顯示超出範圍)        [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];    }        // 下面一層    {        // 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];                // 紅色底字        _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];    }        // 顯示上面一層    [self.view bringSubviewToFront:_upView];        // 給上面一層的frame值做動畫    _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