Question

我当前有一个带有占位符文本的文本视图，只要用户点击该文本视图，该文本视图就会消失，并且如果第一位响应者辞职，则该文本视图中的文本会再次出现（如果文本视图为空）。（此处提供了我用于任何人使用的代码）

*注意，首先将textview的文本颜色设置为浅灰色，然后设置占位符文本。然后使用以下方法：

func textViewShouldBeginEditing(_ textView: UITextView) -> Bool {
    //If it begins editing, then set the color to black
    if (textView.tag == 0){
        textView.text = ""
        textView.textColor = .black
        textView.tag = 1
    }
    return true
}


func textViewDidEndEditing(_ textView: UITextView) {
    if textView.text.isEmpty {
        textView.text = "Example: I started my career as a street wear model based in Maryland. After 3 years of working with some of the top companies there, I moved to LA, where I currently reside. I’ve been featured in shows, 12 magazines, commercials, and a number of music videos. Now, Im currently looking to continue working with clothing companies and campaigns."
        textView.textColor = .lightGray
        textView.tag = 0
    }
}

我想加倍努力。现在，只要文本视图成为第一响应者，文本就会消失。 我希望每当用户真正开始输入文字时，文本就会消失，而不仅仅是在选择文本视图时消失。当屏幕出现时，我会自动将第一响应者设置为文本视图，并计划保留该文本那样。但是因为它是自动设置的，所以您看不到占位符文本。 我只希望每当用户按下一个键时文本视图就消失，而不是因为它被选中。

Answer 1

让我们假设您有一个占位符文本，

let placeholderText = "Example: I started my career as a street wear model based in Maryland. After 3 years of working with some of the top companies there, I moved to LA, where I currently reside. I’ve been featured in shows, 12 magazines, commercials, and a number of music videos. Now, Im currently looking to continue working with clothing companies and campaigns."

在调用textView的{{1}}之前，您正在storyboard或viewDidLoad中将此文本设置为becomeFirstResponder。

然后在这两个委托方法中，您可以实现以下行为，

textView

当前您正在清除func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool { if textView.text == placeholderText { textView.text = "" } return true } func textViewDidEndEditing(_ textView: UITextView) { if textView.text.isEmpty { textView.text = placeholderText } }中的文本，因此，这是您看不到该文本的主要原因。您应该删除此处的清除文字，但是可以继续更改颜色等。

Answer 2

这是代码

class ViewController: UIViewController {

    @IBOutlet weak var textView: UITextView!
    let placeholder = "Example: I started my career as a street wear model based in Maryland. After 3 years of working with some of the top companies there, I moved to LA, where I currently reside. I’ve been featured in shows, 12 magazines, commercials, and a number of music videos. Now, Im currently looking to continue working with clothing companies and campaigns."
    let start = NSRange(location: 0, length: 0)
    override func viewDidLoad() {
        super.viewDidLoad()
        textView.delegate = self
        textView.text = placeholder
    }
}

extension ViewController: UITextViewDelegate {
    func textViewDidChangeSelection(_ textView: UITextView) {
        // Moves cursor to start when tapped on textView with placeholder
        if textView.text == placeholder {
            textView.selectedRange = start
        }
    }
    func textViewDidChange(_ textView: UITextView) {
        // Manages state of text when changed
        if textView.text.isEmpty {
            textView.text = placeholder
            textView.textColor = .lightGray
        } else if textView.text != placeholder {
            textView.textColor = .black
        }
    }
    func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
        // Called when you're trying to enter a character (to replace the placeholder)
        if textView.text == placeholder {
            textView.text = ""
        }
        return true
    }
}

更新＃1：最大长度

func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
    // Called when you're trying to enter a character (to replace the placeholder)
    if textView.text == placeholder {
        textView.text = ""
    } else if textView.text.count >= 175 && text.count > 0 {
        // Now it can delete symbols but can't enter new
        return false
    }
    return true
}

尝试通过按住“擦除”按钮清除textView时存在一个小错误。占位符未显示。不会以某种方式调用textViewDidChange方法（与shouldChangeTextIn不同步）。可能的解决方法https://stackoverflow.com/a/9169556/5228431

带第一响应者的UITextView的占位符文本混合

2 个答案: