iOS UI-Lable标签、NStimer定时器和RunLoop超级死循环

    // 标签UILable -显示文字
    // 1.创建标签
    UILabel *lable = [[UILabel alloc] init];
    // 2.设置标签的坐标和大小
    [lable setFrame:CGRectMake(0,20, 375, 50)];
    // 3.标签内容
    lable.text = @"";
    // 设置字体
    lable.font = [UIFont systemFontOfSize:20];
    // 设置字体颜色
    lable.textColor = [UIColor blackColor];
    // 设置内容换行
    lable.numberOfLines = 0;
    //设置圆角
    lable.layer.cornerRadius = 10;
    lable.layer.masksToBounds = NO;
    // 设置标签内容居中
    lable.textAlignment = NSTextAlignmentCenter;
    // 设置标签背景
    lable.backgroundColor = [UIColor blackColor];
    // 加载图片
    UIImageView *tempView = [[UIImageView alloc] init];
    [tempView setFrame:CGRectMake(255, 0, 120, 50)];
    tempView.image = [UIImage imageNamed:@"1.png"];
    // 4.在当前视图之上加载子视图
    [self.view addSubview:lable];
    [lable addSubview:tempView];

#import "ViewController.h"

@interface ViewController ()
{
    NSTimer *timer;
    NSInteger length;
}
@property (weak, nonatomic) IBOutlet UILabel *lable;

@end

@implementation ViewController

-(void) lableMove
{
    if (self.lable.frame.origin.y>667) {
        length = -10;
    }
    else if (self.lable.frame.origin.y<0)
    {
        length = 10;
    }
    CGRect rect = self.lable.frame;
    rect.origin.y +=length;
    self.lable.frame = rect;
    
    if (self.lable.frame.origin.y>700) {
        [timer invalidate];
        [self.lable removeFromSuperview];
    }
}

- (void)viewDidLoad {
    [super viewDidLoad];
    /*
     NSTimeInterval 计时器响应时间间隔
     target：计时器的响应者
     selector：计时器的响应方法
     userInfo：nil
     repeats：计时器是否重复响应
     */
    length = 10;
    timer = [NSTimer timerWithTimeInterval:0.1 target:self selector:@selector(lableMove) userInfo:nil repeats:YES];
    
    //将定时器插入runLoop（超级死循环）中
    [[NSRunLoop currentRunLoop]  addTimer:timer forMode:NSRunLoopCommonModes];
}