//发现在iphone 6 and iPhone plus 上面键盘不出来。后来查了下原来要在模拟器里设置下

var inputText =  UITextField(frame: CGRectMake(0, 200, self.view.bounds.size.width, 30))
        inputText.text = ""
        inputText.delegate = self
        backView.addSubview(inputText)


     func textFieldShouldReturn(textField: UITextField) -> Bool {
        
        textField .resignFirstResponder()
        var b :Bool
       return true
    }