背景滚动动画

{

    NSTimer *scrollBackground;

}

- (void)viewDidLoad {

[super viewDidLoad];

//背景滚动动画

NSArray *imageArray = @[_image1,_image2];

//userInfo:imageArray

scrollBackground=

[NSTimer scheduledTimerWithTimeInterval:0.1 target:self

selector:@selector(scrollBackground:) userInfo:imageArray repeats:YES];

}

- (void)scrollBackground:(NSTimer *)timer

NSArray *images = timer.userInfo;

//遍历这个数组改变背景图片的y坐标

for(UIImageView *image in images) {

//让图片下落

image.frame=CGRectMake(image.frame.origin.x, image.frame.origin.y

+1, [[UIScreenmainScreen]bounds].size.width, [[UIScreenmainScreen]bounds].size.height);

//判断是否到达临界点出屏幕后改变y坐标位置回收到屏幕上方等待下落

if(image.frame.origin.y>= [[UIScreen mainScreen]bounds].size.height) {

image.frame=CGRectMake(image.frame.origin.x,-[[UIScreen

mainScreen]bounds].size.height,[[UIScreen

mainScreen]bounds].size.width, [[UIScreen

mainScreen]bounds].size.height);

}

}