Question

我有一个看起来像这样的视图控制器：

class SpotViewController: UIViewController {
  let spot: Spot

  init(spot: Spot) {
    self.spot = spot
    super.init(nibName: "SpotViewController", bundle: nil)
  }

  override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    print("viewWillAppear: \(view.frame)") # => (0.0, 0.0, 600.0, 600.0)
  }

  override func viewDidLoad() {
    super.viewDidLoad()

    print("viewDidLoad: \(view.frame)") # => (0.0, 0.0, 600.0, 600.0)
  }
}

当我通过let spotViewController = SpotViewController(spot: spot)实例化视图控制器并将其推送到导航控制器时，viewDidLoad和viewWillAppear中的结果帧都不正确。它给了我(0.0, 0.0, 600.0, 600.0)这是接口构建器中的大小。

为什么会发生这种情况以及使用xib实例化视图控制器以确保框架正确的正确方法是什么？

Answer 1

这将解决您的问题，UIViewController从xib加载，在viewDidLoad期间保持xib大小：

extension UIViewController {
    public override class func initialize() {
        struct Static {
            static var token: dispatch_once_t = 0
        }
        if self !== UIViewController.self {
            return
        }
        dispatch_once(&Static.token) {
            pb_applyFixToViewFrameWhenLoadingFromNib()
        }
    }

    @objc func pb_setView(view: UIView!) {
        // View is loaded from xib file
        if nibBundle != nil && storyboard == nil {
            view.frame = UIScreen.mainScreen().bounds
            view.layoutIfNeeded()
        }
        pb_setView(view)
    }

    private class func pb_applyFixToViewFrameWhenLoadingFromNib() {
        UIViewController.swizzleMethodSelector(NSSelectorFromString("setView:"), withSelector: #selector(UIViewController.pb_setView(_:)))
        UICollectionView.swizzleMethodSelector(#selector(UICollectionView.layoutSubviews), withSelector: #selector(UICollectionView.pb_layoutSubviews))
        UITableView.swizzleMethodSelector(#selector(UITableView.layoutSubviews), withSelector: #selector(UITableView.pb_layoutSubviews))
    }
}

extension UITableView {
    @objc private func pb_layoutSubviews() {
        if dataSource == nil {
            super.layoutSubviews()
        } else {
            pb_layoutSubviews()
        }
    }
}

extension UICollectionView {
    @objc private func pb_layoutSubviews() {
        if dataSource == nil {
            super.layoutSubviews()
        } else {
            pb_layoutSubviews()
        }
    }
}

在实例化ViewController w / xib时，帧大小不正确

1 个答案: