ios-计时器示范：一闪一闪View(动画效果)

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本示例实现的动画：UIView定时消失随后又闪现，即一闪一闪的动画

所采用的技术：定时器(NSTimer) + 动画(beginAnimations/commitAnimations)

具体实现步骤：

1、在.h文件中定义一个变量和一个Method：

2、在.m文件中打开与关闭定时器，以及绑定Method:

3、启动计时器：

第二步：动画部分

在handleScollTimer:方法中写动画代码：

#import "FlashViewController.h"@interface FlashViewController ()
{NSTimer *showTimer;//计时器变量UIView * scanLine;}
要执行的方法
//-(void)handleScrollTimer:(NSTimer *)theTimer;     -(void)startTimer;
@end@implementation FlashViewController- (void)viewDidLoad {[super viewDidLoad];// Do any additional setup after loading the view.self.view.backgroundColor = [UIColor whiteColor];scanLine = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 50, 50)];scanLine.backgroundColor = [UIColor blueColor];[self.view addSubview:scanLine];//开启线程[self performSelectorOnMainThread:@selector(startTimer) withObject:nil waitUntilDone:YES];}- (void)didReceiveMemoryWarning {[super didReceiveMemoryWarning];// Dispose of any resources that can be recreated.
}- (void)viewDidAppear:(BOOL)animated
{///页面显示完毕的时候执行//重新打开定时器[showTimer setFireDate:[NSDate distantPast]];
}-(void)startTimer
{//定义时间计数器:每隔2秒执行一次handleScrollTimer方法showTimer = [NSTimer scheduledTimerWithTimeInterval:2.0target:selfselector:@selector(handleScrollTimer:)userInfo:nilrepeats:true];[[NSRunLoop currentRunLoop] addTimer:showTimer forMode:NSDefaultRunLoopMode];
}///页面消失完毕的时候执行
-(void)viewDidDisappear:(BOOL)animated
{//关闭定时器[showTimer setFireDate:[NSDate distantFuture]];
}-(void)handleScrollTimer:(NSTimer *)theTimer
{scanLine.alpha = 1.0;[UIView beginAnimations:@"scanLine" context:nil];[UIView setAnimationDuration:0.8];[UIView setAnimationCurve:UIViewAnimationCurveLinear];scanLine.alpha = 0.05;[UIView commitAnimations];
}