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];
}