Question

添加依赖旋转的约束后，我的UIScrollView停止工作。我将两组约束放置在两个数组中，每次旋转后，我激活其中一个约束并停用第二个约束。它可以在立即激活约束（constraint.isActive = true）之前起作用，并且只有一组。

func setupLayout() {
    navigationItem.hidesBackButton = true
    navigationController?.navigationBar.barTintColor = #colorLiteral(red: 0.1450980392, green: 0.1960784314, blue: 0.2509803922, alpha: 1)
    setViewBackground()

    let guide = self.view.safeAreaLayoutGuide
    view.addSubview(scrollView)
    scrollView.addSubview(contentView)
    contentView.addSubview(topLeftViewContainer)
    topLeftViewContainer.addSubview(idTextField)
    topLeftViewContainer.addSubview(passTextField)
    contentView.addSubview(bottomRightViewContainer)
    bottomRightViewContainer.addSubview(logInButton)
    bottomRightViewContainer.addSubview(registerButton)
    // MARK: - Portrait Constraints -

    //scrollView
    portraitConstraints.append(scrollView.topAnchor.constraint(equalTo: guide.topAnchor))
    scrollVievBottomConstraint = NSLayoutConstraint(item: scrollView, attribute: .bottom, relatedBy: .equal, toItem: guide, attribute: .bottom, multiplier: 1.0, constant: 0)
    portraitConstraints.append(scrollVievBottomConstraint)
    portraitConstraints.append(scrollView.leadingAnchor.constraint(equalTo: guide.leadingAnchor))
    portraitConstraints.append(scrollView.trailingAnchor.constraint(equalTo: guide.trailingAnchor))

    //contentView
    portraitConstraints.append(contentView.topAnchor.constraint(equalTo: scrollView.topAnchor))
    portraitConstraints.append(contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor))
    portraitConstraints.append(contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor))
    portraitConstraints.append(contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor))
    portraitConstraints.append(contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor))

    //topLeftViewContainer
    portraitConstraints.append(topLeftViewContainer.topAnchor.constraint(equalTo: contentView.topAnchor))
    portraitConstraints.append(topLeftViewContainer.heightAnchor.constraint(equalTo: guide.heightAnchor, multiplier: 0.5))
    portraitConstraints.append(topLeftViewContainer.leadingAnchor.constraint(equalTo: contentView.leadingAnchor))
    portraitConstraints.append(topLeftViewContainer.trailingAnchor.constraint(equalTo: contentView.trailingAnchor))

    //idTextField
    portraitConstraints.append(idTextField.heightAnchor.constraint(equalToConstant: 20))
    portraitConstraints.append(idTextField.widthAnchor.constraint(equalToConstant: 180))
    portraitConstraints.append(idTextField.topAnchor.constraint(equalTo: topLeftViewContainer.topAnchor, constant: 50))
    portraitConstraints.append(idTextField.centerXAnchor.constraint(equalTo: topLeftViewContainer.centerXAnchor))

    //passTextField
    portraitConstraints.append(passTextField.heightAnchor.constraint(equalToConstant: 20))
    portraitConstraints.append(passTextField.widthAnchor.constraint(equalToConstant: 180))
    portraitConstraints.append(passTextField.topAnchor.constraint(equalTo: idTextField.bottomAnchor, constant: 20))
    portraitConstraints.append(passTextField.centerXAnchor.constraint(equalTo: topLeftViewContainer.centerXAnchor))

    //bottomRightViewContainer
    portraitConstraints.append(bottomRightViewContainer.heightAnchor.constraint(equalTo: guide.heightAnchor, multiplier: 0.5))
    portraitConstraints.append(bottomRightViewContainer.topAnchor.constraint(equalTo: topLeftViewContainer.bottomAnchor))
    portraitConstraints.append(bottomRightViewContainer.bottomAnchor.constraint(equalTo: contentView.bottomAnchor))
    portraitConstraints.append(bottomRightViewContainer.leadingAnchor.constraint(equalTo: contentView.leadingAnchor))
    portraitConstraints.append(bottomRightViewContainer.trailingAnchor.constraint(equalTo: contentView.trailingAnchor))

    //logInButton
    portraitConstraints.append(logInButton.heightAnchor.constraint(equalToConstant: 30))
    portraitConstraints.append(logInButton.widthAnchor.constraint(equalToConstant: 120))
    portraitConstraints.append(logInButton.topAnchor.constraint(lessThanOrEqualTo: bottomRightViewContainer.topAnchor, constant: 50))
    portraitConstraints.append(logInButton.centerXAnchor.constraint(equalTo: bottomRightViewContainer.centerXAnchor))

    //registerButton
    portraitConstraints.append(registerButton.heightAnchor.constraint(equalToConstant: 30))
    portraitConstraints.append(registerButton.widthAnchor.constraint(equalToConstant: 120))
    portraitConstraints.append(registerButton.topAnchor.constraint(equalTo: logInButton.bottomAnchor, constant: 20))
    portraitConstraints.append(registerButton.centerXAnchor.constraint(equalTo: bottomRightViewContainer.centerXAnchor))

    // MARK: - Landscape Constraints -

    //scrollView
    landscapeConstraints.append(scrollView.topAnchor.constraint(equalTo: guide.topAnchor))
    scrollVievBottomConstraint = NSLayoutConstraint(item: scrollView, attribute: .bottom, relatedBy: .equal, toItem: guide, attribute: .bottom, multiplier: 1.0, constant: 0)
    landscapeConstraints.append(scrollVievBottomConstraint)
    landscapeConstraints.append(scrollView.leadingAnchor.constraint(equalTo: guide.leadingAnchor))
    landscapeConstraints.append(scrollView.trailingAnchor.constraint(equalTo: guide.trailingAnchor))

    //contentView
    landscapeConstraints.append(contentView.topAnchor.constraint(equalTo: scrollView.topAnchor))
    landscapeConstraints.append(contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor))
    landscapeConstraints.append(contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor))
    landscapeConstraints.append(contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor))
    landscapeConstraints.append(contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor))

    //topLeftViewContainer
    landscapeConstraints.append(topLeftViewContainer.topAnchor.constraint(equalTo: contentView.topAnchor))
    landscapeConstraints.append(topLeftViewContainer.widthAnchor.constraint(equalTo: guide.widthAnchor, multiplier: 0.5))
    landscapeConstraints.append(topLeftViewContainer.leadingAnchor.constraint(equalTo: contentView.leadingAnchor))
    landscapeConstraints.append(topLeftViewContainer.bottomAnchor.constraint(equalTo: guide.bottomAnchor))

    //idTextField
    landscapeConstraints.append(idTextField.heightAnchor.constraint(equalToConstant: 20))
    landscapeConstraints.append(idTextField.widthAnchor.constraint(equalToConstant: 180))
    landscapeConstraints.append(idTextField.topAnchor.constraint(equalTo: topLeftViewContainer.centerYAnchor, constant: -30))
    landscapeConstraints.append(idTextField.centerXAnchor.constraint(equalTo: topLeftViewContainer.centerXAnchor))

    //passTextField
    landscapeConstraints.append(passTextField.heightAnchor.constraint(equalToConstant: 20))
    landscapeConstraints.append(passTextField.widthAnchor.constraint(equalToConstant: 180))
    landscapeConstraints.append(passTextField.topAnchor.constraint(equalTo: idTextField.bottomAnchor, constant: 20))
    landscapeConstraints.append(passTextField.centerXAnchor.constraint(equalTo: topLeftViewContainer.centerXAnchor))

    //bottomRightViewContainer
    landscapeConstraints.append(bottomRightViewContainer.widthAnchor.constraint(equalTo: guide.widthAnchor, multiplier: 0.5))
    landscapeConstraints.append(bottomRightViewContainer.topAnchor.constraint(equalTo: contentView.topAnchor))
    landscapeConstraints.append(bottomRightViewContainer.bottomAnchor.constraint(equalTo: guide.bottomAnchor))
    landscapeConstraints.append(bottomRightViewContainer.trailingAnchor.constraint(equalTo: contentView.trailingAnchor))

    //logInButton
    landscapeConstraints.append(logInButton.heightAnchor.constraint(equalToConstant: 30))
    landscapeConstraints.append(logInButton.widthAnchor.constraint(equalToConstant: 120))
    landscapeConstraints.append(logInButton.topAnchor.constraint(lessThanOrEqualTo: bottomRightViewContainer.centerYAnchor, constant: -30))
    landscapeConstraints.append(logInButton.centerXAnchor.constraint(equalTo: bottomRightViewContainer.centerXAnchor))

    //registerButton
    landscapeConstraints.append(registerButton.heightAnchor.constraint(equalToConstant: 30))
    landscapeConstraints.append(registerButton.widthAnchor.constraint(equalToConstant: 120))
    landscapeConstraints.append(registerButton.topAnchor.constraint(equalTo: logInButton.bottomAnchor, constant: 20))
    landscapeConstraints.append(registerButton.centerXAnchor.constraint(equalTo: bottomRightViewContainer.centerXAnchor))

    NotificationCenter.default.addObserver(self, selector: #selector(keyBoardWillShow(notification:)), name: .UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyBoardWillHide(notification:)), name: .UIKeyboardWillHide, object: nil)

    NSLayoutConstraint.activate(portraitConstraints)
}


// MARK: - Keyboard Handling

@objc func keyBoardWillShow(notification: NSNotification){
    let userInfo:NSDictionary = notification.userInfo! as NSDictionary
    let keyboardFrame:NSValue = userInfo.value(forKey: UIKeyboardFrameEndUserInfoKey) as! NSValue
    let keyboardRectangle = keyboardFrame.cgRectValue
    let keyboardHeight = keyboardRectangle.height - view.safeAreaInsets.bottom
    scrollVievBottomConstraint.constant = -keyboardHeight
    scrollView.setNeedsUpdateConstraints()
    self.view.layoutIfNeeded()

    print("SHOW KEYBOARD")
}
@objc func keyBoardWillHide(notification: NSNotification){
    scrollVievBottomConstraint.constant = 0
    scrollView.setNeedsUpdateConstraints()
    self.view.layoutIfNeeded()

    print("HIDE KEYBOARD")
}

// MARK: - Orientation -

override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
    if UIDevice.current.orientation.isLandscape {
        NSLayoutConstraint.deactivate(portraitConstraints)
        NSLayoutConstraint.activate(landscapeConstraints)
    } else {
        NSLayoutConstraint.deactivate(landscapeConstraints)
        NSLayoutConstraint.activate(portraitConstraints)
    }
}

}

Answer 1

问题可能出在以下方面：

//topLeftViewContainer
landscapeConstraints.append(topLeftViewContainer.topAnchor.constraint(equalTo: contentView.topAnchor))
landscapeConstraints.append(topLeftViewContainer.widthAnchor.constraint(equalTo: guide.widthAnchor, multiplier: 0.5))
landscapeConstraints.append(topLeftViewContainer.leadingAnchor.constraint(equalTo: contentView.leadingAnchor))
landscapeConstraints.append(topLeftViewContainer.bottomAnchor.constraint(equalTo: guide.bottomAnchor))

guide.bottomAnchor或contentView.bottomAnchor？

// bottomRightViewContainer

landscapeConstraints.append(bottomRightViewContainer.widthAnchor.constraint(equalTo: guide.widthAnchor, multiplier: 0.5))
landscapeConstraints.append(bottomRightViewContainer.topAnchor.constraint(equalTo: contentView.topAnchor))
landscapeConstraints.append(bottomRightViewContainer.bottomAnchor.constraint(equalTo: guide.bottomAnchor))
landscapeConstraints.append(bottomRightViewContainer.trailingAnchor.constraint(equalTo: contentView.trailingAnchor))

guide.widthAnchor和guide.bottomAnchor还是contentView.widthAnchor和contentView.bottomAnchor？

更改约束后constUIScrollView不起作用

1 个答案: