UITextField和UITextView

UITextField

基本功能

import UIKitclass ViewController: UIViewController {    var textField: UITextField!    override func viewDidLoad() {    super.viewDidLoad()        textField = UITextField(frame: CGRect(x: 0, y: 0, width: 200, height: 31))    textField.borderStyle = .RoundedRect        textField.contentVerticalAlignment = .Center        textField.textAlignment = .Center        textField.text = "Sir Richard Branson"    textField.center = view.center    view.addSubview(textField)      }  }

效果如下：

使用代理

下面的例子通过代理实现了一个统计字符数的功能，并且实时更新。

import UIKitclass ViewController: UIViewController, UITextFieldDelegate {  var textField: UITextField!  var label: UILabel!    func calculateAndDisplayTextFieldLengthWithText(text: String){        var characterOrCharacters = "Character"    if text.characters.count != 1{      characterOrCharacters += "s"    }        let stringLength = text.characters.count        label.text = "\(stringLength) \(characterOrCharacters)"      }      func textField(paramTextField: UITextField,    shouldChangeCharactersInRange range: NSRange,    replacementString string: String) -> Bool{            guard let textFieldText = paramTextField.text else {        return false      }            let text = NSString(string: textFieldText)            let wholeText =      text.stringByReplacingCharactersInRange(        range, withString: string)            calculateAndDisplayTextFieldLengthWithText(wholeText)            return true        }    func textFieldShouldReturn(paramTextField: UITextField) -> Bool{    paramTextField.resignFirstResponder()    return true  }  override func viewDidLoad() {    super.viewDidLoad()        textField = UITextField(frame:      CGRect(x: 38, y: 30, width: 220, height: 31))    textField.delegate = self    textField.borderStyle = .RoundedRect    textField.contentVerticalAlignment = .Center    textField.textAlignment = .Center    textField.text = "Sir Richard Branson"    view.addSubview(textField)        label = UILabel(frame: CGRect(x: 38, y: 61, width: 220, height: 31))    view.addSubview(label)    calculateAndDisplayTextFieldLengthWithText(textField.text!)      }}

效果如下：

UITextView

基本功能

import UIKitclass ViewController: UIViewController {    var textView: UITextView?    override func viewDidLoad() {    super.viewDidLoad()        textView = UITextView(frame: view.bounds)    if let theTextView = textView{      theTextView.text = "Some text goes here..."            theTextView.contentInset =        UIEdgeInsets(top: 10, left: 0, bottom: 0, right: 0)            theTextView.font = UIFont.systemFontOfSize(16)      view.addSubview(theTextView)    }      }  }

效果如下：

当点击文字时键盘会自动弹出，占了大概一半的空间。如果用户要输入大量的文字，键盘则会阻挡用户的输入。

下面的例子实现了这样的功能，当用户输到最后一行时，自动加载新的空行。

import UIKitclass ViewController: UIViewController {    var textView: UITextView?    let defaultContentInset =  UIEdgeInsets(top: 10, left: 0, bottom: 0, right: 0)    func handleKeyboardDidShow (notification: NSNotification){      /* Get the frame of the keyboard */    let keyboardRectAsObject =    notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue        /* Place it in a CGRect */    var keyboardRect = CGRectZero        keyboardRectAsObject.getValue(&keyboardRect)      /* Give a bottom margin to our text view that makes it    reach to the top of the keyboard */    textView!.contentInset =      UIEdgeInsets(top: defaultContentInset.top,        left: 0, bottom: keyboardRect.height, right: 0)  }    func handleKeyboardWillHide(notification: NSNotification){    textView!.contentInset = defaultContentInset  }    override func viewDidLoad() {    super.viewDidLoad()        textView = UITextView(frame: view.bounds)    if let theTextView = textView{      theTextView.text = "Some text goes here..."      theTextView.font = UIFont.systemFontOfSize(16)      theTextView.contentInset = defaultContentInset            view.addSubview(theTextView)            NSNotificationCenter.defaultCenter().addObserver(        self,        selector: "handleKeyboardDidShow:",        name: UIKeyboardDidShowNotification,        object: nil)                  NSNotificationCenter.defaultCenter().addObserver(        self,        selector: "handleKeyboardWillHide:",        name: UIKeyboardWillHideNotification,        object: nil)          }      }    deinit{    NSNotificationCenter.defaultCenter().removeObserver(self)  }  }