代码很简单 主要看看

+ (void)animateWithDuration:(NSTimeInterval)duration delay:(NSTimeInterval)delay options:(UIViewAnimationOptions)options animations:(void (^)(void))animations completion:(void (^)(BOOL finished))completion

方法的使用

代码如下：

- (void)viewDidLoad

{

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

arr=[[NSMutableArray alloc] init];

CGSize size=[[UIScreen mainScreen] bounds].size;

float x=size.width/3.0;

float y=size.height/3.0;

for (int i=0; i<9; i++) {

UIButton *button=[[UIButton alloc] initWithFrame:CGRectZero];

button.backgroundColor=[UIColor redColor];

int d=i%3;

int t=i/3;

button.frame=CGRectMake(0+x*d, 0+y*t,x-20, y-10);

button.tag=i;

[self.view addSubview:button];

[arr addObject:button];

}

[self showIn];

}

-(void)showIn{

int r=arc4random()%9;

UIButton *button=[arr objectAtIndex:r];

[UIView animateWithDuration:0.1 delay:1.0 options:UIViewAnimationOptionCurveLinear animations:^{

button.backgroundColor=[UIColor clearColor];

} completion:^(BOOL finished) {

button.backgroundColor=[UIColor redColor];

[self showIn];

}];

}