利用定时器展示动态文字

#import "ViewController.h"

static NSInteger count = 0;

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UILabel *label;

@property (nonatomic, strong)NSArray *array;
/** 添加定时器 */
@property (nonatomic, strong) NSTimer *time;

@end

@implementation ViewController

- (NSArray *)array
{
    if(!_array)
    {
        _array = [NSArray arrayWithObjects:@"1...",@"2....",@"3.....",@"4......", nil];
    }
    return _array;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.time = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(runLabel) userInfo:nil repeats:YES];
    [self.time fire]; // 立即触发定时器
//    [time setFireDate:[NSDate distantPast]]; // 开启定时器
//    [time setFireDate:[NSDate distantFuture]]; // 暂停定时器
}

- (void)runLabel
{
    self.label.text = self.array[count++ % self.array.count];
}

/** 移除定时器 */
- (void)removeTimer
{ // 定时器一旦被停止，不会重新开始，要被移除。
    [self.time invalidate];
    self.time = nil;
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end