ios - 将内容置于 UIScrollView (Pager) iOS 中心

Question

我有两个启用了寻呼机的 UIScrollview，我动态添加了 12 个 UIImageView。

我有下一个代码:

int content_size_width = self.view.frame.size.width - arrow_left.frame.size.width - arrow_right.frame.size.width;
int content_size_height = green_scroll.frame.size.height;
first_sign_scroll.frame = CGRectMake(0, 0, content_size_width, content_size_height);
first_sign_scroll.pagingEnabled=YES;
first_sign_scroll.contentSize = CGSizeMake(content_size_width*12,1);
int pos = 0;
for(int i=1;i<13;i++){

    UIImage *img = [UIImage imageNamed:images_array[i-1]];
    UIImageView *image = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, img.size.width*multiple, img.size.height*multiple)];
    [image setImage: img];

    float middle_scroll_x = green_scroll.frame.size.width/2;
    float middle_scroll_y = green_scroll.frame.size.height/2;

    image.center = CGPointMake(middle_scroll_x + pos,middle_scroll_y);
    [green_scroll addSubview:image];
    pos +=content_size_width;

}

我为蓝色卷轴做了同样的代码。

问题是图像并不像您在图像中看到的那样位于 ScrollView 的中心。垂直居中不起作用。

有人可以帮我吗？

谢谢。

Answer 1

试试这个方法居中:

@implementation ContentInsetCenteredScrollView

    - (void)centerContent {
        CGFloat top = 0, left = 0;
        if (self.contentSize.width < self.bounds.size.width) {
            left = (self.bounds.size.width-self.contentSize.width) * 0.5f;
        }
        if (self.contentSize.height < self.bounds.size.height) {
            top = (self.bounds.size.height-self.contentSize.height) * 0.5f;
        }
        self.contentInset = UIEdgeInsetsMake(top, left, top, left);
    }

    - (void)didAddSubview:(UIView *)subview {
        [super didAddSubview:subview];
        [self centerContent];
    }

    - (void)scrollViewDidZoom:(__unused UIScrollView *)scrollView {
        [self centerContent];
    }

    - (void)setFrame:(CGRect)frame {
        [super setFrame:frame];
        [self centerContent];
    }