IOS跑马灯效果，实现文字水平无间断滚动

ViewController.h

 #import <UIKit/UIKit.h>
 
 @interface ViewController : UIViewController{
     NSTimer           *timer;
     UIScrollView      *scrollViewText;
 }
 
 @property (nonatomic ,strong) NSArray *arrData;
 
 @end

ViewController.m

 //
 //  ViewController.m
 //  跑马灯文字广告
 //
 //  Created by Time.X on 16/2/15.
 //  Copyright © 2016年 Time.X. All rights reserved.
 //
 
 #import "ViewController.h"
 
 #pragma mark - Class define variable
 #define K_MAIN_VIEW_SCROLL_HEIGHT 80.0f
 #define K_MAIN_VIEW_SCROLL_TEXT_TAG 300
 #define K_MAIN_VIEW_TEME_INTERVAL 0.35         //计时器间隔时间(单位秒)
 #define K_MAIN_VIEW_SCROLLER_SPACE 20          //每次移动的距离
 #define K_MAIN_VIEW_SCROLLER_LABLE_WIDTH  280  //字体宽度
 #define K_MAIN_VIEW_SCROLLER_LABLE_MARGIN 20   //前后间隔距离
 
 @interface ViewController ()
 
 @end
 
 @implementation ViewController
 
 #pragma mark - Class property
 @synthesize arrData;
 
 - (void)viewDidLoad {
     [super viewDidLoad];
 
     [self initView];
 }
 
 - (void)didReceiveMemoryWarning {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }
 
 #pragma mark - Custom method
 //初始化数据
 -(void) initView{
 
     if (!self.arrData) {
         self.arrData = @[
                          @{
                              @"newsId"   :@"",
                               @"newsImg"  :@"http://bg.fx678.com/HTMgr/upload/UpFiles/20150707/sy_2015070709395519.jpg",
                               @"newsTitle" : @"三大理由欧元任性抗跌，欧元区峰会将为希腊定调"
                                   },
                          @{
                              @"newsId"   :@,
                               @"newsImg"   :@"http://bg.fx678.com/HTMgr/upload/UpFiles/20150707/sy_2015070709273545.jpg",
                               @"newsTitle" :@"欧盟峰会或现希腊转机，黄金打响1162保卫战"
                               },
                          @{
                              @"newsId"    :@,
                               @"newsImg"   :@"http://bg.fx678.com/HTMgr/upload/UpFiles/20150707/2015070706533134.jpg",
                               @"newsTitle" :@"希腊困局欧元不怕，油价服软暴跌8%"
                               }
                          ];
     }
 
     //文字滚动
     [self initScrollText];
 
     //开启滚动
     [self startScroll];
 }
 
 //文字滚动初始化
 -(void) initScrollText{
 
     //获取滚动条
     scrollViewText = (UIScrollView *)[self.view viewWithTag:K_MAIN_VIEW_SCROLL_TEXT_TAG];
     if(!scrollViewText){
         scrollViewText = [[UIScrollView alloc] initWithFrame:CGRectMake(, , self.view.frame.size.width, K_MAIN_VIEW_SCROLL_HEIGHT)];
         scrollViewText.showsHorizontalScrollIndicator = NO;   //隐藏水平滚动条
         scrollViewText.showsVerticalScrollIndicator = NO;     //隐藏垂直滚动条
         scrollViewText.tag = K_MAIN_VIEW_SCROLL_TEXT_TAG;
         [scrollViewText setBackgroundColor:[UIColor grayColor]];
 
         //清除子控件
         for (UIView *view in [scrollViewText subviews]) {
             [view removeFromSuperview];
         }
 
         //添加到当前视图
         [self.view addSubview:scrollViewText];
     }
 
     if (self.arrData) {
 
         CGFloat offsetX =  ,i = , h = ;
 
         //设置滚动文字
         UILabel *labText = nil;
         for (NSDictionary *dicTemp in self.arrData) {
             labText = [[UILabel alloc] initWithFrame:CGRectMake(
                                                                 i * (K_MAIN_VIEW_SCROLLER_LABLE_WIDTH + K_MAIN_VIEW_SCROLLER_LABLE_MARGIN),
                                                                 (K_MAIN_VIEW_SCROLL_HEIGHT - h) / ,
                                                                 K_MAIN_VIEW_SCROLLER_LABLE_WIDTH,
                                                                 h)];
             [labText setFont:[UIFont systemFontOfSize:]];
             [labText setTextColor:[UIColor whiteColor]];
             labText.text = dicTemp[@"newsTitle"];
             offsetX += labText.frame.origin.x;
 
             //添加到滚动视图
             [scrollViewText addSubview:labText];
 
             i++;
         }
 
         //设置滚动区域大小
         [scrollViewText setContentSize:CGSizeMake(offsetX, )];
     }
 }
 
 //开始滚动
 -(void) startScroll{
 
     if (!timer)
         timer = [NSTimer scheduledTimerWithTimeInterval:K_MAIN_VIEW_TEME_INTERVAL target:self selector:@selector(setScrollText) userInfo:nil repeats:YES];
 
     [timer fire];
 }
 
 //滚动处理
 -(void) setScrollText{
 
     CGFloat startX = scrollViewText.contentSize.width - K_MAIN_VIEW_SCROLLER_LABLE_WIDTH - K_MAIN_VIEW_SCROLLER_LABLE_MARGIN;
 
     [UIView animateWithDuration:K_MAIN_VIEW_TEME_INTERVAL *  animations:^{
         CGRect rect;
         CGFloat offsetX = 0.0;
 
         for (UILabel *lab in scrollViewText.subviews) {
 
             rect = lab.frame;
             offsetX = rect.origin.x - K_MAIN_VIEW_SCROLLER_SPACE;
             if (offsetX < -K_MAIN_VIEW_SCROLLER_LABLE_WIDTH)
                 offsetX = startX;
 
             lab.frame = CGRectMake(offsetX, rect.origin.y, rect.size.width, rect.size.height);
         }
 
         NSLog(@"offsetX:%f",offsetX);
 
     }];
 
 }
 
 @end