Resizing text field in inputAccessoryView

问题:

I have been trying to get a UITextView to resize all week. I don't see how this should be done, so I have decided to include practically all relevant code.

I have this conversation view:

This conversationview is a UIViewController with a UITableView inside (using constraints). I have a custom UIView subclass ConversationToolbar set as inputAccessoryView (the UIViewController containing it can become the first responder, so the view is visible at all times), that contains 2 subviews. One for the UITextView and left and right buttons, and one for the emoticons. The emoticons only show when the left button is tapped:

And when one is chosen, it shows in a floating label:

I now have trouble to resize this UITextView when multiple lines are used. I have tried calculating all frames myself, but then that seems to conflict with my constraints in some weird way. Almost always is the UITextView either too small or it resizes only after I press another key to update the view. Or the UITextView gets bigger over the keyboard, or it slides out of view when the keyboard is dismissed.

I have removed all resizing abilities from my code and I would like to know what I need to do to make this resize.

In my ConversationViewController:

var toolbar: ConversationToolbar!

override var inputAccessoryView: UIView! {
    get {
        if toolbar == nil {
            toolbar = NSBundle.mainBundle().loadNibNamed("ConversationToolbar", owner: nil, options: nil).last! as ConversationToolbar
            toolbar.frame.size = CGSize(width: UIScreen.mainScreen().bounds.size.width, height: 80)
            toolbar.delegate = self
            toolbar.setDraft(conversation.draft)
        }
        return toolbar
    }
}

With ConversationToolbar.xib being:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="6254" systemVersion="14D87p" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES">
    <dependencies>
        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="6247"/>
    </dependencies>
    <objects>
        <placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner"/>
        <placeholder placeholderIdentifier="IBFirstResponder" id="-2" customClass="UIResponder"/>
        <view contentMode="scaleToFill" id="iN0-l3-epB" customClass="ConversationToolbar" customModule="Heaven_Help" customModuleProvider="target">
            <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>
            <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
            <subviews>
                <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="s5O-PN-dtz">
                    <rect key="frame" x="0.0" y="554" width="600" height="46"/>
                    <subviews>
                        <button opaque="NO" contentMode="scaleToFill" horizontalCompressionResistancePriority="749" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="pbw-hg-sNn">
                            <rect key="frame" x="0.0" y="0.0" width="36" height="46"/>
                            <inset key="contentEdgeInsets" minX="8" minY="0.0" maxX="8" maxY="0.0"/>
                            <state key="normal" title="