Swift消息文本区

我正在创建一个新应用程序，我想添加如下消息区域：

当用户单击文本区域时，将显示键盘，用户开始编写消息，右键将是发送按钮，文本区域将增长如下：

最简单的方法是什么

---

我有个主意，但我认为这不是最好的办法。我正在考虑用程序解决它。在viewLoad中，我将以编程方式创建按钮和文本区域，然后当用户开始写入时，我将再次创建它们

我还建议用代码解决这个问题。加载视图时，必须创建所有按钮，如果用户开始写入，则应重新创建部分按钮。但请记住，您必须确保Textfield是同一个实例，或者您必须通过代码将响应者提交给它。

如中所述，您可以使用

UITextField

委托方法来截获不同的状态

例如，您可以使用来处理用户开始编辑的时刻。在这里，您可以处理约束以放大文本字段（请注意，如果使用“自动布局”，则必须使用约束，不要进行帧修改）：

之后，您可以处理其他代理：

func textFieldShouldEndEditing(textField: UITextField!) -> Bool {  
    return false
}

func textFieldShouldReturn(textField: UITextField!) -> Bool { 
  textField.resignFirstResponder()

    return true
}

---

在这里，您可以重复动画或执行任何您想要的操作。

除了文本字段代理，您还需要处理键盘：

override func viewDidLoad() {
super.viewDidLoad()

NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillAppear:", name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillDisappear:", name: UIKeyboardWillHideNotification, object: nil)}

override func viewWillDisappear(animated: Bool) {
super.viewWillDisappear(true)
NSNotificationCenter.defaultCenter().removeObserver(self)}

func keyboardWillAppear(notification: NSNotification){

var userInfo:NSDictionary = notification.userInfo!
var keyboardSize:CGSize = userInfo.objectForKey(UIKeyboardFrameBeginUserInfoKey)!.CGRectValue().size

var contentInsets:UIEdgeInsets = UIEdgeInsetsMake(0, 0, 0, 0)

self.tableView.contentInset = contentInsets
self.tableView.scrollIndicatorInsets = contentInsets

var messageFrame:CGRect = self.commentField.frame
messageFrame.origin.y -= keyboardSize.height
self.commentField.frame = messageFrame}

func keyboardWillDisappear(notification: NSNotification){
var userInfo:NSDictionary = notification.userInfo!
var keyboardSize:CGSize = userInfo.objectForKey(UIKeyboardFrameBeginUserInfoKey)!.CGRectValue().size

UIView.beginAnimations(nil, context: nil)
UIView.setAnimationDuration(0.25)
self.tableView.contentInset = UIEdgeInsetsZero
UIView.commitAnimations()

self.tableView.scrollIndicatorInsets = UIEdgeInsetsZero

var messageFrame:CGRect = self.commentField.frame
messageFrame.origin.y += keyboardSize.height
self.commentField.frame = messageFrame}

---

除了textfield委托，您还需要处理键盘。

override func viewDidLoad() {
super.viewDidLoad()

NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillAppear:", name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector:"keyboardWillDisappear:", name: UIKeyboardWillHideNotification, object: nil)}

override func viewWillDisappear(animated: Bool) {
super.viewWillDisappear(true)
NSNotificationCenter.defaultCenter().removeObserver(self)}

func keyboardWillAppear(notification: NSNotification){

var userInfo:NSDictionary = notification.userInfo!
var keyboardSize:CGSize = userInfo.objectForKey(UIKeyboardFrameBeginUserInfoKey)!.CGRectValue().size

var contentInsets:UIEdgeInsets = UIEdgeInsetsMake(0, 0, 0, 0)

self.tableView.contentInset = contentInsets
self.tableView.scrollIndicatorInsets = contentInsets

var messageFrame:CGRect = self.commentField.frame
messageFrame.origin.y -= keyboardSize.height
self.commentField.frame = messageFrame}

func keyboardWillDisappear(notification: NSNotification){
var userInfo:NSDictionary = notification.userInfo!
var keyboardSize:CGSize = userInfo.objectForKey(UIKeyboardFrameBeginUserInfoKey)!.CGRectValue().size

UIView.beginAnimations(nil, context: nil)
UIView.setAnimationDuration(0.25)
self.tableView.contentInset = UIEdgeInsetsZero
UIView.commitAnimations()

self.tableView.scrollIndicatorInsets = UIEdgeInsetsZero

var messageFrame:CGRect = self.commentField.frame
messageFrame.origin.y += keyboardSize.height
self.commentField.frame = messageFrame}