UICollectionView的sectionInset的意思

UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];

layout.sectionInset = UIEdgeInsetsMake(20, marginLR, 20, marginLR);//设置其边界

 

UIEdgeInsetsMake(CGFloat top, CGFloat left, CGFloat bottom, CGFloat right) 

top表示的cell与布局顶部的间隙,如果0的情况

layout.sectionInset = UIEdgeInsetsMake(0, marginLR, 20, marginLR);//设置其边界

layout.sectionInset = UIEdgeInsetsMake(0, marginLR, 20, marginLR);//设置其边界