                 self.conversationCollectionView.contentInset.bottom = self.messageToolbar.intrinsicContentSize().height + keyboardHeight
 
             }, completion: { (finished) -> Void in
-                println("self.keyboardHeight: \(self.keyboardHeight)")
-
                 self.keyboardShowTimes -= 1
             })
         }
     }
 
     func handleKeyboardWillHideNotification(notification: NSNotification) {
-        println("hideKeyboard")
-
         conversationCollectionViewContentOffsetBeforeKeyboardWillHide = conversationCollectionView.contentOffset
 
         if let userInfo = notification.userInfo {

    // MARK: Keyboard

    func handleKeyboardWillShowNotification(notification: NSNotification) {
        println("showKeyboard")

        keyboardShowTimes += 1



    var conversationCollectionViewHasBeenMovedToBottomOnce = false

    // Keyboard 动画相关
    var conversationCollectionViewContentOffsetBeforeKeyboardWillShow = CGPointZero
    var conversationCollectionViewContentOffsetBeforeKeyboardWillHide = CGPointZero
    var isKeyboardVisible = false
    var keyboardHeight: CGFloat = 0

    var keyboardShowTimes = 0 {
        willSet {
