UITextView 与第一响应者混合的占位符文本

Question

我目前有一个带有占位符文本的文本视图，每当用户点击文本视图时，占位符文本就会消失，并且如果文本视图为空，则每当第一响应者辞职时，文本视图中的文本就会重新出现。（这是我使用的代码，以防有人想使用它）

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*注意，首先将textview的文本颜色设置为浅灰色，并设置占位符文本。然后使用这些方法：

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func textViewShouldBeginEditing(_ textView: UITextView) -> Bool {\n    //If it begins editing, then set the color to black\n    if (textView.tag == 0){\n        textView.text = ""\n        textView.textColor = .black\n        textView.tag = 1\n    }\n    return true\n}\n\n\nfunc textViewDidEndEditing(_ textView: UITextView) {\n    if textView.text.isEmpty {\n        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\xe2\x80\x99ve 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."\n        textView.textColor = .lightGray\n        textView.tag = 0\n    }\n}\n

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我想把事情更上一层楼。现在，只要文本视图成为第一响应者，文本就会消失。我希望每当用户实际开始输入时文本就会消失，而不仅仅是在选择文本视图时消失。当屏幕出现时，我自动将第一响应者设置为文本视图，并且我计划保持这种状态。但由于它是自动设置的，因此您无法看到占位符文本。我只希望每当用户按下某个键时文本视图就会消失，而不是因为它被选中。

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Answer 1

假设您有一个占位符文本，如下所示，

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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\xe2\x80\x99ve 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."\n

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并且您在调用之前将此文本设置为textViewinstoryboard或 in 。viewDidLoadbecomeFirstRespondertextView

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然后在这两个委托方法中您可以实现此行为，如下所示，

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func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {\n    if textView.text == placeholderText {\n        textView.text = ""\n    }\n    return true\n}\n\nfunc textViewDidEndEditing(_ textView: UITextView) {\n    if textView.text.isEmpty {\n        textView.text = placeholderText\n    }\n}\n

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目前您正在清除so中的文本textViewShouldBeginEditing，这是您看不到该文本的主要原因。您应该删除清除那里的文本，但您可以继续更改颜色等。

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