平时QQ在输入时，其整个view上滚，但实际上直接召唤键盘并不会这样，为了达到这样的效果，我们可以设置一个textfield，并把它的delegate给view，并在view中添加如下代码。即重载animateTextField函数，其中movementDistance为收缩距离，需要根据不同机型进行调整。
func animateTextField(textField: UITextField, up: Bool) {
let movementDistance:CGFloat = -210
let movementDuration: Double = 0.3
var movement:CGFloat = 0
if up {
movement = movementDistance
}
else {
movement = -movementDistance
}
UIView.beginAnimations("animateTextField", context: nil)
UIView.setAnimationBeginsFromCurrentState(true)
UIView.setAnimationDuration(movementDuration)
self.view.frame = CGRectOffset(self.view.frame, 0, movement)
UIView.commitAnimations()
}
func textFieldDidBeginEditing(textField: UITextField) {
self.animateTextField(textField, up:true)
}
func textFieldDidEndEditing(textField: UITextField) {
self.animateTextField(textField, up:false)
}
func textFieldShouldReturn(textField: UITextField) -> Bool // called when 'return' key pressed. return NO to ignore.
{
textField.resignFirstResponder()
return true;
}