Question

我正在修改UIView高度的约束，包括nameTextField和使用SnapKit的superView inputContainerView。我安排nameTextField的高度等于inputContainerView的高度的三分之一。我的目的是在按下SegmentedControl时删除nameTextField。当我尝试修改常量时，它工作得很好。但是当我尝试将乘数高度值从（1/3）修改为0时，有时它会崩溃，有时我写的其他textField（passwordTextField和emailTextField）也会消失。我正在使用updateContraint来更新一些约束。我该如何解决这个问题？谢谢

inputContainerView.snp.makeConstraints { (make) in
        make.centerX.equalTo(view.snp.centerX)
        make.centerY.equalTo(view.snp.centerY)
        // constraintAnchor is equal to offset
        make.width.equalTo(view.snp.width).offset(-24)
        make.height.equalTo(150)
    }

    // constraint for nameTextField
    inputContainerView.addSubview(nameTextField)
    //x y width height constraint using Snap Kit
    nameTextField.snp.makeConstraints { (make) in
        make.left.equalTo(inputContainerView.snp.left).offset(12)
        make.top.equalTo(inputContainerView.snp.top)
        make.width.equalTo(inputContainerView.snp.width)
        make.height.equalTo(inputContainerView.snp.height).multipliedBy(0.333)
    }
func handleLoginRegisterChange() {
    let title = loginRegisterSegmentedControl.titleForSegment(at: loginRegisterSegmentedControl.selectedSegmentIndex)
    loginRegisterButton.setTitle(title, for: .normal)

    // change height of inputcontainerview
    if loginRegisterSegmentedControl.selectedSegmentIndex == 0 {
        inputContainerView.snp.updateConstraints({ (update) in
            update.height.equalTo(100)
        })
        nameTextField.snp.remakeConstraints({ (remake) in
            remake.height.equalTo(inputContainerView.snp.height).multipliedBy(0)
        })
    } else if loginRegisterSegmentedControl.selectedSegmentIndex == 1 {
        inputContainerView.snp.updateConstraints({ (update) in
            update.height.equalTo(150)
        })
        nameTextField.snp.remakeConstraints({ (remake) in
            remake.height.equalTo(inputContainerView.snp.height).multipliedBy(0.333)
        })
    }
}
// constraint for nameSeparator
    inputContainerView.addSubview(nameSeparator)
    //x y width height constraint using Snap Kit
    nameSeparator.snp.makeConstraints { (make) in
        make.left.equalTo(inputContainerView.snp.left).offset(12)
        make.top.equalTo(nameTextField.snp.bottom)
        make.right.equalTo(inputContainerView.snp.right).offset(-12)
        make.height.equalTo(1)
    }

    // constraint for emailTextField
    inputContainerView.addSubview(emailTextField)
    //x y width height constraint using Snap Kit
    emailTextField.snp.makeConstraints { (make) in
        make.left.equalTo(inputContainerView.snp.left).offset(12)
        make.top.equalTo(nameSeparator.snp.bottom)
        make.width.equalTo(inputContainerView.snp.width)
        make.height.equalTo(inputContainerView.snp.height).multipliedBy(0.333)
    }

    // constraint for emailSeparator
    inputContainerView.addSubview(emailSeparator)
    //x y width height constraint using Snap Kit
    emailSeparator.snp.makeConstraints { (make) in
        make.left.equalTo(inputContainerView.snp.left).offset(12)
        make.top.equalTo(emailTextField.snp.bottom)
        make.right.equalTo(inputContainerView.snp.right).offset(-12)
        make.height.equalTo(1)
    }

    // constraint for passwordTextField
    inputContainerView.addSubview(passwordTextField)
    passwordTextField.snp.makeConstraints { (make) in
        make.left.equalTo(inputContainerView.snp.left).offset(12)
        make.top.equalTo(emailSeparator.snp.bottom)
        make.width.equalTo(inputContainerView.snp.width)
        make.height.equalTo(inputContainerView.snp.height).multipliedBy(0.333)
    }

这是显示的图像：

Answer 1

remakeConstraints将删除所有先前安装的约束。因此，您可能正在删除所有顶级，领先等等约束并重新安装高度。您应该使用updateConstraints或者最初使用所有声明的约束重新制作。

使用Swift 3中的SnapKit以编程方式修改约束以删除一个UIView

1 个答案: