let textfield = UITextField(frame: CGRectMake(10.0,10.0,200.0,40.0))
self.view.addSubview(textfield)

// 字体属性设置
textfield.textColor = UIColor.blackColor()
textfield.font = UIFont(name: "GillSans",size: 15.0)
textfield.textAlignment = NSTextAlignment.Left
textfield.placeholder = "textfield的使用"
textfield.secureTextEntry = false

<pre name="code" class="objc">// 光标颜色
textfield.textColor = UIColor.greenColor()

textfield.enabled = true
textfield.userInteractionEnabled = true

// 样式背景属性
textfield.backgroundColor = UIColor.lightGrayColor()
textfield.borderStyle = UITextBorderStyle.Line
// let image = UIImage(named: "normalImage")
// textfield.background = image

// 图标
let leftview = UIImageView(image: UIImage(named: "normalImage"))
leftview.frame = CGRectMake(0.0,0.0,30.0,30.0)
textfield.leftviewmode = UITextFieldviewmode.Always
textfield.leftView = leftview
let rightview = UIImageView(image: UIImage(named: "hightImage"))
rightview.frame = CGRectMake(0.0,30.0)
textfield.rightviewmode = UITextFieldviewmode.Always
textfield.rightView = rightview

// 代理，注意添加代理协议，及实现代理方法
textfield.delegate = self

// 添加协议
class ViewController: UIViewController,UITextFieldDelegate {
 
    override func viewDidLoad() {
 
   }
}

// 代理方法
// MARK: - UITextFieldDelegate
func textFieldShouldBeginEditing(textField: UITextField) -> Bool {
        
        print("1 textFieldShouldBeginEditing")
        
        return true
}
    
func textFieldDidBeginEditing(textField: UITextField) {
        print("2 textFieldDidBeginEditing")
}
    
func textField(textField: UITextField,shouldChangeCharactersInRange range: NSRange,replacementString string: String) -> Bool {
        print("3 textField")
        
        return true
}
 
func textFieldShouldEndEditing(textField: UITextField) -> Bool {
        print("4 textFieldShouldEndEditing")
        print("text：\(textField.text) length = \(textField.text?.characters.count)")
        return true
}
    
func textFieldDidEndEditing(textField: UITextField) {
        print("5 textFieldDidEndEditing")
}
    
func textFieldShouldClear(textField: UITextField) -> Bool {
        
        print("6 textFieldShouldClear")
        
        return true
}
    
func textFieldShouldReturn(textField: UITextField) -> Bool {
        
        // 结束编辑
        textField.resignFirstResponder()
        
        print("7 textFieldShouldReturn")
        
        return true
}

// 编辑属性设置
textfield.clearButtonMode = UITextFieldviewmode.WhileEditing

// 输入设置
textfield.keyboardType = UIKeyboardType.WebSearch
textfield.returnKeyType = UIReturnKeyType.Done
        
// 自定义输入源控件
// let inputview = UIButton(frame: CGRectMake(0.0,CGRectGetWidth(self.view.bounds),100.0))
// inputview.setImage(UIImage(named: "normalImage"),forState: UIControlState.Normal)
// inputview.backgroundColor = UIColor.lightGrayColor()
// inputview.addTarget(self,action: Selector("click:"),forControlEvents: UIControlEvents.TouchUpInside)
// textfield.inputView = inputview
// 自定义输入源控件副视图
let accessoryview = UIView(frame: CGRectMake(0.0,40.0))
accessoryview.backgroundColor = UIColor.greenColor()
let accessoryLeft = UIButton(frame: CGRectMake(10.0,60.0,20.0))
accessoryview.addSubview(accessoryLeft)
accessoryLeft.setTitle("取消",forState: UIControlState.Normal)
accessoryLeft.backgroundColor = UIColor.orangeColor()
accessoryLeft.addTarget(self,action: Selector("leftClick:"),forControlEvents: UIControlEvents.TouchUpInside)
let accessoryRight = UIButton(frame: CGRectMake((CGRectGetWidth(accessoryview.bounds) - 10.0 - 60.0),20.0))
accessoryview.addSubview(accessoryRight)
accessoryRight.setTitle("确定",forState: UIControlState.Normal)
accessoryRight.backgroundColor = UIColor.orangeColor()
accessoryRight.addTarget(self,action: Selector("rightClick:"),forControlEvents: UIControlEvents.TouchUpInside)
textfield.inputAccessoryView = accessoryview

// 自定义输入源控件时响应事件
// MARK: - click
func click(button:UIButton)
{
        self.view.endEditing(true)
}
    
//MARK: - left/right click
func leftClick(button:UIButton)
{
        print("取消")
}
    
func rightClick(button:UIButton)
{
        self.view.endEditing(true)
        print("确定")
}

// 其他
// 第一响应，即进入编辑状态
// textfield.becomeFirstResponder()
// 结束响应，即结束编辑
// textfield.resignFirstResponder()
// 发通知-输入改变
NSNotificationCenter.defaultCenter().addObserver(self,selector: Selector("textFiledEditChanged:"),name: UITextFieldTextDidChangeNotification,object: textfield)

// 通知响应方法-限制输入长度
// MARK: - 通知响应方法
func textFiledEditChanged(notification:NSNotification)
{
        let textField:UITextField! = notification.object as! UITextField
        if (textField != nil)
        {
            let text:String! = textField.text
            let length = text.characters.count
            if (length > 20)
            {
                textField.text = text.substringToIndex(text.startIndex.advancedBy(20))
            }
        }
}

注意：不能同时设置clearButtonMode、rightviewmode/rightView属性，否则只有rightviewmode/rightView有效。