二维码扫描框动画

-(void) createUI{

    //创建背景框

   UIImageView * bgView = [[UIImageViewalloc] initWithFrame:CGRectMake(100,100, 100, 100)];

    bgView.image = [UIImageimageNamed:@"HR_border"];

    [self.viewaddSubview:bgView];

    

    //创建扫描线

    _linView = [[UIImageViewalloc] initWithFrame:CGRectMake(100,100, 100, 10)];

    _linView.image = [UIImageimageNamed:@"HR_scan_line.png"];

    [self.viewaddSubview:_linView];

    

    //增加动画

   CADisplayLink * dislink = [CADisplayLinkdisplayLinkWithTarget:selfselector:@selector(moveLine)];

    [dislink addToRunLoop:[NSRunLoopmainRunLoop] forMode:NSDefaultRunLoopMode];

    

}

-(void)moveLine{

   CGRect rect = _linView.frame;

    rect.origin.y +=1;

   if (rect.origin.y >=195 ) {

        rect.origin.y =100;

    }

   _linView.frame = rect;

}