二维码扫描框动画

-(void) createUI{

    //创建背景框

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

    bgView.image = [UIImage imageNamed:@"HR_border"];

    [self.view addSubview:bgView];

    

    //创建扫描线

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

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

    [self.view addSubview:_linView];

    

    //增加动画

    CADisplayLink * dislink = [CADisplayLink displayLinkWithTarget:self selector:@selector(moveLine)];

    [dislink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

    

}

-(void)moveLine{

    CGRect rect = _linView.frame;

    rect.origin.y += 1;

    if (rect.origin.y >= 195 ) {

        rect.origin.y = 100;

    }

    _linView.frame = rect;

}