在iOS11上当使用如下代码设置时
UIButton *shareButton = [UIButton buttonWithType:(UIButtonTypeCustom)];
shareButton.frame = CGRectMake(0, 0, 30, 30);
shareButton.backgroundColor = [UIColor blueColor];
[shareButton setImage:[UIImage imageNamed:@"mv_actionIconSaveToAlbum"] forState:(UIControlStateNormal)];
UIBarButtonItem *rightBtnItem = [[UIBarButtonItem alloc] initWithCustomView:shareButton];
self.navigationItem.rightBarButtonItem = rightBtnItem;
如果图片大小大于按钮设置的大小 ,设置的button的frame将不起作用。系统将采用最大区域展示。图片大小小于设置的button的frame时 不会出现这个问题。