七彩霓虹灯 制作

在ui学习，用简单地uiView和视图控制器制作的霓虹灯效果，在这个过程中要学会使用定时器NSTimer的开启与关闭，这个是实现动态效果的关键一步，在使用时可以查看API文档查看，也可以上网查询；

初始化
+ (NSTimer *)timerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(id)userInfo repeats:(BOOL)yesOrNo;

• (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(id)userInfo repeats:(BOOL)yesOrNo;

 //开启定时器   [_timer setFireDate:[NSDate distantPast]];

  //暂停定时器   [_timer invalidate];

这里timer的内存并没有释放，如果释放了可能造成程序崩溃，这是我现在没有解决的

(http://img.blog.csdn.net/20151121174843569)- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view.    //布局子视图    for (int i = 0; i < 10; i ++) {        UIView *view = [[UIView alloc] initWithFrame:CGRectMake ( 15 +15*(i + 1), 15 * (i +1), 300 - i * 30, 600 -i *30 )] ;        [self.view addSubview:view];        view.backgroundColor = [UIColor colorWithRed:KColorKey green:KColorKey blue:KColorKey alpha:1.0];        view.tag = 100 + i;        [view release];    }    //添加按钮    UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];        btn.frame = CGRectMake(80, 620, 80, 40);        btn.backgroundColor = [UIColor greenColor];        [btn setTitle:@"开始" forState:UIControlStateNormal];    [btn addTarget:self action:@selector(begin:) forControlEvents:UIControlEventTouchUpInside];        [self.view addSubview:btn];    UIButton *btn1 = [UIButton buttonWithType:UIButtonTypeSystem];    btn1.frame = CGRectMake(180, 620, 80, 40);    btn1.backgroundColor = [UIColor greenColor];    [btn1 setTitle:@"取消" forState:UIControlStateNormal];    [btn1 addTarget:self action:@selector(stop:) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:btn1];   }//开始事件- (void)begin: (UIButton *)btn {     //添加定时器    _timer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(fromout) userInfo:nil repeats:YES];    //开启定时器   [_timer setFireDate:[NSDate distantPast]];}//实现事件//从里向外- (void)fromout {    UIColor *tem = [self.view viewWithTag:100].backgroundColor;    for (int i = 100; i < 110; i ++) {        [self.view viewWithTag:i].backgroundColor = [self.view viewWithTag:i+ 1].backgroundColor;    }    [self.view viewWithTag:100 + 9].backgroundColor = tem;    //从外向里    //    UIColor *temp = [self.view viewWithTag:100 + 9].backgroundColor;    //    for (int i = 100 + 9; i >= 100; i--) {    //        [self.view viewWithTag:i].backgroundColor = [self.view viewWithTag:i-1].backgroundColor;    //    }    //    [self.view viewWithTag:100].backgroundColor = temp;}- (void)stop: (UIButton*) btn {   //暂停定时器   [_timer invalidate];   }@end