iOS

来源：互联网发布：office mac 汉化补丁编辑：程序博客网时间：2024/06/05 14:31

UITextView继承于UIScrollView，所以它也是一个可滚动控件。UITextView是我们开发过程中显示多行文本的首选，它支持显示大量文本内容，并且支持使用自定义样式信息和编辑功能。

首先我们创建一个UITextView，并设置部分属性

class ViewController: UIViewController {    lazy var textView: UITextView = {        let tv = UITextView()        // 背景颜色        tv.backgroundColor = UIColor.gray        // 文本内容        tv.text = "患难可以试验一个人的品格；非常的境遇才可以显出非常的气节；，风平浪静的海面，所有的船只都可以并驱竞争；命运的铁拳击中要害的时候，只有大勇大智的人才能够处之泰然。——莎士比亚"        // 文本颜色        tv.textColor = UIColor.white        // 文本字体大小        tv.font = UIFont.systemFont(ofSize: 18.0)        // 文本对齐方式        tv.textAlignment = .center        return tv    }()    override func viewDidLoad() {        super.viewDidLoad()        addTextView()    }        func addTextView() {        view.addSubview(textView)        textView.snp.makeConstraints { (make) in            make.left.top.right.bottom.equalToSuperview().inset(50)        }    }}

效果如下：

常用属性

是否可以选中操作

textView.isSelectable = true

默认是true，可以选中，一旦设置为false，将不能够进行选中操作，默认可选中效果

富文本，可以通过设置attributedText属性设置文本样式，如：

  // 创建可变属性字符串  let attribute = NSMutableAttributedString(string: textView.text)  // 设置段落样式  let paragraphStyle = NSMutableParagraphStyle()  paragraphStyle.alignment = .center  paragraphStyle.lineSpacing = 10  // 设置属性字典  let dic = [NSAttributedStringKey.foregroundColor: UIColor.red,             NSAttributedStringKey.font: UIFont.boldSystemFont(ofSize: 22.0),             NSAttributedStringKey.paragraphStyle: paragraphStyle]  // 添加属性字典  attribute.addAttributes(dic, range: NSMakeRange(16, textView.text.count - 16))  // 设置textView的attributedText  textView.attributedText = attribute

输入视图

func addInputVeiw() {    let inputView = UIView(frame: CGRect(x: 0, y: 0, width: view.bounds.size.width, height: 200))    inputView.backgroundColor = UIColor.red    textView.inputView = inputView}

输入键盘附属视图

func addInputAccessoryView(){    let inputAccessoryView = UIView(frame: CGRect(x: 0, y: 0, width: view.bounds.size.width, height: 100))    inputAccessoryView.backgroundColor = UIColor.red    textView.inputAccessoryView = inputAccessoryView}

获得焦点后选中现有文本内容，输入内容时清除当前选中文本内容

textView.clearsOnInsertion = true

文本内容与边界的间距

textView.textContainerInset = UIEdgeInsetsMake(20, 20, 20, 20)

设置光标颜色

textView.tintColor = UIColor.red

代理函数

对于textView的输入进行监听，我们经常设置delegate,相关方法如下：

extension ViewController: UITextViewDelegate {    //将要开始编辑    func textViewShouldBeginEditing(_ textView: UITextView) -> Bool {        return true    }    //将要开始编辑    func textViewShouldEndEditing(_ textView: UITextView) -> Bool {        return true    }    //已经开始编辑    func textViewDidBeginEditing(_ textView: UITextView) {    }    //结束编辑    func textViewDidEndEditing(_ textView: UITextView) {    }    //文本将要改变    func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {        return true    }    //文本发生改变    func textViewDidChange(_ textView: UITextView) {    }    //焦点发生改变    func textViewDidChangeSelection(_ textView: UITextView) {    }    //是否允许对文本中的URL进行操作    func textView(_ textView: UITextView, shouldInteractWith URL: URL, in characterRange: NSRange) -> Bool {        return true    }    //是否允许对文本中的富文本进行操作    func textView(_ textView: UITextView, shouldInteractWith textAttachment: NSTextAttachment, in characterRange: NSRange) -> Bool {      return true    }}

通知

extension NSNotification.Name {        public static let UITextViewTextDidBeginEditing: NSNotification.Name    public static let UITextViewTextDidChange: NSNotification.Name    public static let UITextViewTextDidEndEditing: NSNotification.Name}

常用功能

1）UITextView显示边框

textView.layer.borderColor = UIColor.cyan.cgColortextView.layer.borderWidth = 2.0

2）根据textView的内容计算textView的大小，参考

首先设置textView不可滚动，否则每次换行都会滚动一下

func addTextView() {    view.addSubview(textView)    textView.snp.makeConstraints { (make) in        make.left.top.right.equalToSuperview().inset(50)        make.height.equalTo(40)    }    textView.isScrollEnabled = false}

然后在文本改变的代理方法中计算

 //文本发生改变  func textViewDidChange(_ textView: UITextView) {      let fixedWidth = textView.frame.size.width      let newSize = textView.sizeThatFits(CGSize(width: fixedWidth, height: CGFloat.infinity))      //更新高度约束      textView.snp.updateConstraints { (make) in          make.height.equalTo(newSize.height)      } }

3）限制文字输入的个数，参考这里

 func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {     if(textView.text.count > 20 && range.length == 0) {        print("Please summarize in 20 characters or less")            return false     }   return true}

或者使用如下方法进行更准确控制，输入到最大数量之后无法输入：

 func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {        let selectedRange = textView.markedTextRange        var pos: UITextPosition? = nil        if let _sel = selectedRange {            pos = textView.position(from: _sel.start, offset: 0)        }        if selectedRange != nil, pos != nil {            let startOffset = textView.offset(from: textView.beginningOfDocument, to: selectedRange!.start)            if startOffset < maxCount {                return true            } else {                return false            }        }        let comcatStr = (textView.text as NSString).replacingCharacters(in: range, with: text)        let canInputLen = maxCount - comcatStr.length        if canInputLen >= 0 {            return true        } else {            let len = text.length + canInputLen            let rg = NSRange.init(location: 0, length: max(len, 0))            if rg.length > 0 {                var s = ""                if text.canBeConverted(to: .ascii) {                    s = (text as NSString).substring(with: rg)                } else {                    var idx = 0                    var trimString = ""                    (text as NSString).enumerateSubstrings(in: NSRange(location: 0, length: text.length), options: .byComposedCharacterSequences, using: { (subString, _, _, stop) in                        if idx >= rg.length {                            stop.pointee = true                            return                        }                        trimString = (trimString as NSString).appending(subString ?? "")                        idx += 1                    })                    s = trimString                }                textView.text = (textView.text as NSString).replacingCharacters(in: range, with: s)            }            return false        }    }    func textViewDidChange(_ textView: UITextView) {        let selectedRange = textView.markedTextRange        var pos: UITextPosition? = nil        if let _sel = selectedRange {            pos = textView.position(from: _sel.start, offset: 0)        }        if selectedRange != nil, pos != nil {            return        }        let textViewText: String = textView.text        let existTextNum = textViewText.length        if existTextNum > maxCount {            let s = (textViewText as NSString).substring(to: maxCount)            textView.text = s        }    }

4）添加默认文字placeholder

方法一，添加一个label，通过监听是否输入内容来控制是否显示

首先创建一个label

 lazy var palceholderLabel: UILabel = {        let label = UILabel(frame: CGRect(origin: CGPoint(x: 5, y: 5), size: CGSize.zero))        label.text = "input some..."        label.textColor = UIColor.lightGray        label.sizeToFit()        return label    }()

添加到textView上

 textView.addSubview(palceholderLabel)

根据输入的内容控制是否显示

func textViewDidChange(_ textView: UITextView) {    palceholderLabel.isHidden = !textView.text.isEmpty}

其他的方式，可以看这里

5）自定义选择内容菜单栏

我们再看新闻的时候，常常在点选文字后会弹出菜单进行选择，复制等操作。这里我们也可以自己在菜单栏上添加一些其他内容，比如：分享到朋友圈，邮件。

  func customMenu() {        let mail = UIMenuItem(title: "邮件", action: #selector(ViewController.onMail))        let weixin = UIMenuItem(title: "分享到朋友圈", action: #selector(ViewController.shareToWeiChat))        let menu = UIMenuController()        menu.menuItems = [mail,weixin]    }        @objc func onMail(){        print("mail")    }        @objc func shareToWeiChat(){        print("shareToWeiChat")    }

6）使用textView显示html内容，参考

func addHtml() {    let htmlString = "<html>" +            "<head>" +            "<style>" +            "body {" +            "background-color: rgb(230, 230, 230);" +            "font-family: 'Arial';" +            "text-decoration:none;" +            "}" +            "</style>" +            "</head>" +            "<body>" +            "<h1>A title</h1>" +            "<p>A paragraph</p>" +            "<b>bold text</b>" +        "</body></head></html>"           let htmlData = NSString(string: htmlString).data(using: String.Encoding.unicode.rawValue)   let options = [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html]   let attributedString = try! NSAttributedString(data: htmlData!, options: options, documentAttributes: nil)   textView.attributedText = attributedString }

7）获取选中的文本内容

 //焦点发生改变    func textViewDidChangeSelection(_ textView: UITextView) {        if let selectedRange = textView.selectedTextRange {            let selectedText = textView.text(in: selectedRange)        }    }

8）修改光标的位置，主要是对selectedRange属性进行修改，设置开始的位置，如，从第三个文字开始显示光标

textView.selectedRange = NSRange(location: 3, length: 0)textView.becomeFirstResponder()

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