iOS实现文字水平无间断滚动效果

#import <uikit/uikit.h>
 
@interface viewcontroller : uiviewcontroller{
  nstimer      *timer;
  uiscrollview   *scrollviewtext;
}
 
@property (nonatomic ,strong) nsarray *arrdata;
 
@end

//
// viewcontroller.m
// 滚动
//
#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 20.0f       //每次移动的距离
#define k_main_view_scroller_lable_width   18.0f  //单个字符宽度(与你设置的字体大小一致)
#define k_main_view_scroller_lable_margin  20.0f  //前后间隔距离
#define k_main_view_scroller_sleep_interval 1    //停留时间
 
 
@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"  :@"201507070942261935",
               @"newsimg" :@"http://www.51sjk.com/Upload/Articles/1/0/258/258708_20210630004507917.jpg",
               @"newstitle":@"三大理由欧元任性抗跌，欧元区峰会将为希腊定调"
             },
             @{
               @"newsid"  :@"201507070929021220",
               @"newsimg"  :@"http://www.51sjk.com/Upload/Articles/1/0/258/258708_20210630004507933.jpg",
               @"newstitle" :@"欧盟峰会或现希腊转机，黄金打响1162保卫战"
             },
             @{
               @"newsid"  :@"201507070656471857",
               @"newsimg"  :@"http://www.51sjk.com/Upload/Articles/1/0/258/258708_2021063000450793301.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(0, 80, 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.scrollenabled = no;          //禁用手动滑动
 
    //横竖屏自适应
    scrollviewtext.autoresizingmask = uiviewautoresizingflexiblewidth;
    scrollviewtext.tag = k_main_view_scroll_text_tag;
    [scrollviewtext setbackgroundcolor:[uicolor graycolor]];
 
    //给滚动视图添加事件
    uitapgesturerecognizer *tapgesture = [[uitapgesturerecognizer alloc] initwithtarget:self action:@selector(scrollerviewclick:)];
    [scrollviewtext addgesturerecognizer:tapgesture];
 
    //添加到当前视图
    [self.view addsubview:scrollviewtext];
  }else{
    //清除子控件
    for (uiview *view in [scrollviewtext subviews]) {
      [view removefromsuperview];
    }
  }
 
  if (self.arrdata) {
 
    cgfloat offsetx = 0 ,i = 0, h = 30;
 
    //设置滚动文字
    uibutton *btntext = nil;
    nsstring *strtitle = [[nsstring alloc] init];
 
    for (nsdictionary *dictemp in self.arrdata) {
 
      strtitle = dictemp[@"newstitle"];
 
      btntext = [uibutton buttonwithtype:uibuttontypecustom];
      [btntext setframe:cgrectmake([self gettitleleft:i],
                     (k_main_view_scroll_height - h) / 2,
                     strtitle.length * k_main_view_scroller_lable_width,
                     h)];
 
      [btntext settitlecolor:[uicolor redcolor] forstate:uicontrolstatenormal];
      [btntext settitle:strtitle forstate:uicontrolstatenormal];
 
      //横竖屏自适应
      btntext.autoresizingmask = uiviewautoresizingflexiblewidth;
      offsetx += btntext.frame.origin.x;
 
      //设置为 no,否则无法响应点击事件
      btntext.userinteractionenabled = no;
 
      //添加到滚动视图
      [scrollviewtext addsubview:btntext];
 
      i++;
    }
 
    //设置滚动区域大小
    [scrollviewtext setcontentsize:cgsizemake(offsetx, 0)];
  }
}
 
 
#pragma mark - 滚动处理
//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{
 
  [uiview animatewithduration:k_main_view_teme_interval * 2 animations:^{
    cgrect rect;
    cgfloat offsetx = 0.0,width = 0.0;
 
    for (uibutton *btntext in scrollviewtext.subviews) {
 
      rect = btntext.frame;
      offsetx = rect.origin.x - k_main_view_scroller_space;
      width = [btntext.titlelabel.text length] * k_main_view_scroller_lable_width;
 
      btntext.frame = cgrectmake(offsetx, rect.origin.y, rect.size.width, rect.size.height);
 
      nslog(@"offsetx:%f",offsetx);
    }
 
    if (offsetx < -width){
      [uiview setanimationsenabled:no];
      [self initscrolltext];
    }else
      [uiview setanimationsenabled:yes];
  }];
 
}
 
 
#pragma mark - 动态获取左边位置
-(float) gettitleleft:(cgfloat) i {
  float left = i * k_main_view_scroller_lable_margin;
 
  if (i > 0) {
    for (int j = 0; j < i; j ++) {
      left += [[self.arrdata objectatindex:j][@"newstitle"] length] * k_main_view_scroller_lable_width;
    }
  }
 
  return left;
}
 
 
#pragma mark - 新闻点击事件
-(void)btnnewsclick:(uibutton *) sender{
 
  nsstring *strnewstitle = sender.titlelabel.text;
 
  uialertview *alert = [[uialertview alloc] initwithtitle:@"系统提示"
                          message:strnewstitle
                          delegate:sender
                     cancelbuttontitle:@"确定"
                     otherbuttontitles:@"其他", nil];
  [alert show];
 
}
 
-(void)scrollerviewclick:(uitapgesturerecognizer*)gesture{
 
  cgpoint touchpoint = [gesture locationinview:scrollviewtext];
 
  for (uibutton *btn in scrollviewtext.subviews) {
 
    if ([btn.layer.presentationlayer hittest:touchpoint]) {
      [self btnnewsclick:btn];
      break;
    }
 
  }
 
}
 
@end