[iOS - swift] UITableView 하단 inset이 자동으로 34로 설정 방지 방법 (contentInsetAdjustmentBehavior)

tableView에 자동으로 설정되는 inset

• contentInsetAdjustmentBehavior 값은 os에서 자동으로 safe area를 고려하여 설정되는 getter 프로퍼티

open class UIScrollView : UIView, NSCoding, UIFocusItemScrollableContainer {
    @available(iOS 11.0, *)
    open var adjustedContentInset: UIEdgeInsets { get }
    ...
}

• 이 값을 직접 set해줄수는 없기 때문에 "contentInsetAdjustmentBehavior"를 사용하여 조절이 가능

open class UIScrollView : UIView, NSCoding, UIFocusItemScrollableContainer {
    /* Configure the behavior of adjustedContentInset.
     Default is UIScrollViewContentInsetAdjustmentAutomatic.
     */
    @available(iOS 11.0, *)
    open var contentInsetAdjustmentBehavior: UIScrollView.ContentInsetAdjustmentBehavior
    ...
}

• 이 값의 default는 automatic이므로 아무런 설정을 해주지 않으면 scrollView의 bottom, top inset값이 자동으로 조절되는 것
  • never로 설정해주면 자동으로 변경 x

@available(iOS 11.0, *)
public enum ContentInsetAdjustmentBehavior : Int, @unchecked Sendable {
    case automatic = 0 // Similar to .scrollableAxes, but for backward compatibility will also adjust the top & bottom contentInset when the scroll view is owned by a view controller with automaticallyAdjustsScrollViewInsets = YES inside a navigation controller, regardless of whether the scroll view is scrollable
    case scrollableAxes = 1 // Edges for scrollable axes are adjusted (i.e., contentSize.width/height > frame.size.width/height or alwaysBounceHorizontal/Vertical = YES)
    case never = 2 // contentInset is not adjusted
    case always = 3 // contentInset is always adjusted by the scroll view's safeAreaInsets
}

예시)

• tableView 준비

private let tableView = {
    let view = UITableView()
    view.register(MyCell.self, forCellReuseIdentifier: "cell")
    view.translatesAutoresizingMaskIntoConstraints = false
    return view
}()

• tableView 레이아웃

override func viewDidLoad() {
    super.viewDidLoad()
    tableView.dataSource = self
    
    view.addSubview(tableView)
    NSLayoutConstraint.activate([
        tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
        tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
        tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
        tableView.topAnchor.constraint(equalTo: view.topAnchor),
    ])
}

• viewDidAppear에서 adjustedContentInset을 출력해보면 상단에 59.0, 하단에 34.0이 존재

print(tableView.adjustedContentInset)
// UIEdgeInsets(top: 59.0, left: 0.0, bottom: 34.0, right: 0.0)

자동으로 설정된 상단 59.0 inset

자동으로 설정된 하단 34.0 inset

• contentInsetAdjustmentBehavior값을 never로 설정

private let tableView = {
    let view = UITableView()
    view.register(MyCell.self, forCellReuseIdentifier: "cell")
    view.contentInsetAdjustmentBehavior = .never // <-
    view.translatesAutoresizingMaskIntoConstraints = false
    return view
}()

• adjustedContentInset값이 모두 0으로 된 것을 확인

* 전체 코드: https://github.com/JK0369/ExLabelStaticHeight

* 참고

- https://developer.apple.com/documentation/uikit/uiscrollview/2902261-contentinsetadjustmentbehavior