change inputAccessoryView's height issue in iOS 8.4 - ios

Question

I made a MessageComposerView like this
import UIKit
protocol MessageComposerDelegate: NSObjectProtocol {
func messageDidChange(messageView: MessageComposerView, height: CGFloat)
func postMessage(message: String)
}
private let maxTextViewHeight: CGFloat = 100.0
class MessageComposerView: UIView, UITextViewDelegate {
#IBOutlet weak var textView: SAMTextView!
#IBOutlet weak var sendButton: UIButton!
weak var delegate:MessageComposerDelegate?
#IBAction func sendButtonAction(sender: UIButton) {
delegate?.postMessage(textView.text)
}
override func awakeFromNib() {
let borderColor = UIColor(white: 0.9, alpha: 1).CGColor
let layer = CALayer()
layer.backgroundColor = borderColor
layer.frame = CGRectMake(0, 0, CGRectGetWidth(UIScreen.mainScreen().bounds), 1.0)
self.layer.addSublayer(layer)
textView.backgroundColor = UIColor.whiteColor()
textView.layer.borderColor = borderColor
textView.layer.borderWidth = 1.0
textView.layer.cornerRadius = 5.0
textView.delegate = self
textView.layoutManager.allowsNonContiguousLayout = false
sendButton.backgroundColor = Color.Red.colorValue
sendButton.tintColor = UIColor.whiteColor()
sendButton.layer.cornerRadius = 5.0
}
//MARK: TextViewDelegate
func textViewDidChange(textView: UITextView) {
self.sendButton.enabled = !self.textView.text!.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet()).isEmpty
textView.scrollEnabled = textView.contentSize.height >= maxTextViewHeight
let height = textView.scrollEnabled ? textView.contentSize.height : textView.intrinsicContentSize().height
delegate?.messageDidChange(self, height: min(height, maxTextViewHeight) + 16.0)
if let selectedTextRange = self.textView.selectedTextRange {
let caretRect = self.textView.caretRectForPosition(selectedTextRange.end);
let height = self.textView.textContainerInset.bottom + caretRect.size.height
self.textView.scrollRectToVisible(CGRectMake(caretRect.origin.x, caretRect.origin.y, caretRect.size.width, height), animated: true)
}
}
}
and in the ViewController when I increase the height of MessageComposerView:
func messageDidChange(messageView: MessageComposerView, height: CGFloat) {
messageView.bounds.size.height = height
self.reloadInputViews()
messageView.textView.reloadInputViews()
}
In iOS 9,It works well.
but in iOS 8.4,The textView and Button not change their frame rightly
So What should I do to fix it in iOS 8.4,Thank you!