如何将占位符设置为Swift中一个视图控制器中的多个文本视图

Question

我有一个视图控制器，其中包含两个文本视图(讲故事和故事描述(。我已经将占位符添加到两个文本视图中，下面的代码将向您显示我如何完成的：

// Setup the story title text field
func setupStoryTitleTextView() {
    storyTitle.textColor = .gray
    storyTitle.text = "Add story title"
    storyTitle.textContainerInset = UIEdgeInsets(top: 10, left: 20, bottom: 10, right: 20)
    self.storyTitle.delegate = self
    view.addSubview(storyTitle)
}
// Setup the storyDescription text view
func setupStoryDescriptionTextView() {
    storyDescription.text = "Description of the story"
    storyDescription.textColor = .gray
    storyDescription.textContainerInset = UIEdgeInsets(top: 10, left: 20, bottom: 300, right: 20)
    self.storyDescription.delegate = self
    view.addSubview(storyDescription)
}
// To remove placeholder text when the user starts typing
func textViewDidBeginEditing(_ textView: UITextView) {
    // Story title text view
    if storyTitle.textColor == .gray {
        storyTitle.text = nil
        storyTitle.textColor = .black
    }
    // Story description text view
    if storyDescription.textColor == .gray {
        storyDescription.text = nil
        storyDescription.textColor = .black
    }
}
// To bring the placeholder back when the text views don't contain any text
func textViewDidEndEditing(_ textView: UITextView) {
    // Story title text view
    if storyTitle.text.isEmpty {
        storyTitle.text = "Add story title"
        storyTitle.textColor = .gray
    }
    // Story description text view
    if storyDescription.text.isEmpty {
        storyDescription.text = "Description of the story"
        storyDescription.textColor = .gray
    }
}

这里发生的事情是，当我点击一个文本视图时，两个文本视图中的占位符都消失了，这是因为执行了textViewDidBeginEditing下的条件。我如何防止这种情况发生？感谢您的任何帮助，谢谢：(

Answer 1

您可以通过分配标签来查看对象(您的textViews(来轻松执行此操作。用 textView.tag = [某些数字]分配标签，然后您也可以添加到类似的条件中：

storyDescription.tag = 1
func textViewDidBeginEditing(_ textView: UITextView) {
    if textView.tag == 1 && storyTitle.textColor == .gray {
        storyTitle.text = nil
        storyTitle.textColor = .black
    }
}

和其他TextView的类似物

Answer 2

// To remove placeholder text when the user starts typing
func textViewDidBeginEditing(_ textView: UITextView) {
    // Story title text view
    if storyTitle.textColor == .gray {
        storyTitle.text = nil
        storyTitle.textColor = .black
    }
    // Story description text view
    if storyDescription.textColor == .gray {
        storyDescription.text = nil
        storyDescription.textColor = .black
    }
}
// To bring the placeholder back when the text views don't contain any text
func textViewDidEndEditing(_ textView: UITextView) {
    // Story title text view
    if storyTitle.text.isEmpty {
        storyTitle.text = "Add story title"
        storyTitle.textColor = .gray
    }
    // Story description text view
    if storyDescription.text.isEmpty {
        storyDescription.text = "Description of the story"
        storyDescription.textColor = .gray
    }
}

此代码将适用于您的两个文本视图。这是错误的，理想情况下，您应该使用代表方法中提供的textView，例如：

func textViewDidBeginEditing(_ textView: UITextView) {
    if textView.textColor == .gray {
        textView.text = nil
        textView.textColor = .black
    }
}
// To bring the placeholder back when the text views don't contain any text
func textViewDidEndEditing(_ textView: UITextView) {
    if textView.text.isEmpty {
        textView.textColor = .gray
    }
    // You can then restore the text depending on which TextView ended the edition, for example:
    if textView == self.storyTitle {
        self.storyTitle.text = "Add story title"
    }
}

顺便说一句，决定基于颜色的占位符或不明确显示占位符可能不是最好的方法，尤其是如果您计划最终支持装饰的字符串。这是另一个讨论，但暂时将起作用