BecomeFirstResponder 和多个 UITextField 焦点

Question

所以我有一个视图 -> UITextField 和 UILabel 是两个 children，我有多个包含 children 的视图。我正在使用下面的委托函数，并将每个 UITextfields 分配为委托 "textFieldShouldReturn(_ textField: UITextField) -> Bool"。但是，当我按下 return 时，它们似乎并没有改变 textField Focus。将此焦点技术与 UITextFields 一起使用，而无需将它们嵌套在视图中。它使我可以毫无问题地改变焦点。为什么在视图中嵌套 UITextField 会导致无法让下一个 UITextField 成为第一响应者？我已经阅读了一些关于第一响应者及其工作原理的内容，但它没有清楚地解释如何解决这个问题。

class ScrollingViewWithFields:UIViewController, UITextFieldDelegate {

let scrollView = UIScrollView()
let contentView = UIView()

var textFields:[UITextField] = []
var labeledTextField:[LabeledTextField] = []

override func viewDidLoad() {
    contentView.backgroundColor = UIColor.white
    contentView.translatesAutoresizingMaskIntoConstraints = false

    view.addSubview(scrollView)
    scrollView.addSubview(contentView)

    scrollView.translatesAutoresizingMaskIntoConstraints = false
    scrollView.backgroundColor = UIColor.white
    let top = view.safeAreaLayoutGuide.topAnchor
    let bottom = view.safeAreaLayoutGuide.bottomAnchor

    NSLayoutConstraint.activate([
        scrollView.topAnchor.constraint(equalTo: top),
        scrollView.bottomAnchor.constraint(equalTo: bottom),
        scrollView.leftAnchor.constraint(equalTo: view.leftAnchor),
        scrollView.rightAnchor.constraint(equalTo: view.rightAnchor)
    ])



    let ltf = LabeledTextField()
    ltf.translatesAutoresizingMaskIntoConstraints = false

    contentView.addSubview(ltf)
    ltf.populate(title: "Hello", font: UIFont.systemFont(ofSize: 14.0))
    ltf.textField.delegate = self
    ltf.textField.tag = 0
    let ltf2 = LabeledTextField()
    ltf2.translatesAutoresizingMaskIntoConstraints = false
    contentView.addSubview(ltf2)
    ltf2.populate(title: "What", font: UIFont.systemFont(ofSize: 14.0))
    ltf2.textField.tag = 1
    ltf2.textField.delegate = self



    self.textFields.append(ltf2.textField)
    self.textFields.append(ltf.textField)

    NSLayoutConstraint.activate([
        ltf.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 8.0),
        ltf.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 8.0),
        ltf.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: 8.0),
        ltf.heightAnchor.constraint(equalToConstant: 60)
    ])

    NSLayoutConstraint.activate([
        ltf2.topAnchor.constraint(equalTo: ltf.bottomAnchor, constant: 8.0),
        ltf2.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 8.0),
        ltf2.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: 8.0),
        ltf2.heightAnchor.constraint(equalToConstant: 60)
        ])

    NSLayoutConstraint.activate([
        contentView.topAnchor.constraint(equalTo: scrollView.topAnchor),
        contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor),
        contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
        contentView.heightAnchor.constraint(equalToConstant:4000)
    ])

}

func textFieldShouldReturn(_ textField: UITextField) -> Bool {

    let tag = textField.tag
    let next = tag + 1

    if next < self.textFields.count {
        let textField = self.textFields[next]

        textField.becomeFirstResponder()
        self.scrollView.contentOffset = CGPoint(x: 0.0, y: textField.frame.origin.y - 8.0)

    } else {
        textField.resignFirstResponder()
    }

    return true
}

}

Answer 1

问题在于您在文本字段上设置标签并将它们放入数组的方式。

ltf.textField.tag = 0
ltf2.textField.tag = 1

self.textFields.append(ltf2.textField)
self.textFields.append(ltf.textField)

标签与数组中的顺序不匹配的问题，因为数组最终将成为 [ltf2.textField, ltf.textField]。我会完全跳过使用标签，只使用数组中的顺序。

func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    if let index = textFields.index(of: textField) {
        let nextIndex = index + 1
        let lastIndex = textFields.count - 1

        if nextIndex <= lastIndex {
            textFields[nextIndex].becomeFirstResponder()
        }
    }
    return true
}

Answer 2

您可以保留内存而不是声明一个数组来保存文本字段并尝试这样的事情

func textFieldShouldReturn(_ textField: UITextField) -> Bool
{
    if let next =  self.view.viewWithTag(textField.tag + 1) as? UITextField
    {            
        next.becomeFirstResponder()
    }         
    else
    {
        textField.resignFirstResponder()
    }
    return true

}

BecomeFirstResponder 和多个 UITextField 焦点

BecomeFirstResponder and Multiple UITextField Focus

ios

swift

uitextfield

becomefirstresponder