iOS UICollectionView 添加footerview

1在这个方法中返回cell

    func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
        if kind == UICollectionView.elementKindSectionFooter {
            let reusableview = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "collectionFooter", for: indexPath) as! CollectionViewFooterView
            reusableview.finishBtn.addTarget(self, action: #selector(finishBtnClick), for: .touchUpInside)
            reusableview.changeBtn.addTarget(self, action: #selector(changeBtnClick), for: .touchUpInside)
            if(self.age.count > 0 && self.sex.count > 0 && self.selectContentArray.count > 0){
                reusableview.finishBtn.backgroundColor = .red
                reusableview.finishBtn.isEnabled = true
            }else{
                reusableview.finishBtn.backgroundColor = .gray
                reusableview.finishBtn.isEnabled = false
            }
            return reusableview
        }else{
            return UICollectionReusableView()
        }
    }

2 设置宽高

layout.footerReferenceSize = CGSize(width: ScreenSize.SCREEN_WIDTH, height: 80)

3 注册自定义footer

collectionView.register(CollectionViewFooterView.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionFooter, withReuseIdentifier: "collectionFooter")