overridefuncviewDidLoad() {
super.viewDidLoad()
//滚动视图的窗口尺寸
scrollView.frame=CGRect(x:0,y:0,width:self.view.frame.width,height:self.view.frame.height)
//定义滚动视图的内容视图尺寸与窗口尺寸一样
scrollView.contentSize.height=self.view.frame.height
scrollViewHeight=self.view.frame.height
//检测键盘出现或消失的状态
NotificationCenter.default.addObserver(self, selector:#selector(showKeyboard), name:NSNotification.Name.UIKeyboardWillShow, object:nil)
NotificationCenter.default.addObserver(self, selector:#selector(hideKeyboard), name:NSNotification.Name.UIKeyboardWillHide, object:nil)
//声明隐藏虚拟键盘的操作
//创建一个单击手势，当手势发生后会调用hidekeyboardTap方法
let hideTap =UITapGestureRecognizer(target:self, action:#selector(hideKeyboardTap))
//设置该手势的单击次数是1次
hideTap.numberOfTapsRequired=1
//设置了当前控制器的视图为可交互
self.view.isUserInteractionEnabled=true
//将该手势识别添加到控制器上
self.view.addGestureRecognizer(hideTap)
}
func hideKeyboardTap(recognizer:UITapGestureRecognizer){
// UIView的endEditing方法用于设置视图的编辑状态（虚拟键盘呈现在屏幕上）时，执行endEditing(true)可以让虚拟键盘消失
self.view.endEditing(true)
}
funcshowKeyboard(notification:Notification){
//获取userInfo字典中健名为[UIKeyboardFrameEndUserInfoKey]的值并强制转化成NSValue类型并赋值给keyboard
letrect = notification.userInfo! [UIKeyboardFrameEndUserInfoKey]as!NSValue
keyboard= rect.cgRectValue
//当虚拟键盘出现后，将滚动视图的实际高度缩小为屏幕高度减去键盘的高度
UIView.animate(withDuration:0.4){
self.scrollView.frame.size.height=self.scrollViewHeight-self.keyboard.size.height
}
}
funchideKeyboard(notification:Notification){
//当键盘消失后，将滚动视图的实际高度改变为屏幕的高度值
UIView.animate(withDuration:0.4){
self.scrollView.frame.size.height=self.view.frame.height
}
}