about dynamic height of custom cell Raw.swift

//
//  TaskCell.swift
//  imuc
//
//  Created by ctslin on 2015/8/13.
//  Copyright (c) 2015年 ctslin. All rights reserved.
//

import UIKit

class TaskCell: UITableViewCell {

  var data: Task!

  var row1, row2, row3: UIView!
  var action, subject, due_date: UILabel!
  var status: UIButton!

  override func awakeFromNib() {
    super.awakeFromNib()
  }

  override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
    super.init(style: style, reuseIdentifier: reuseIdentifier)
    setupUI()
  }

  func setupUI(){

    row1 = contentView.addView()
    row2 = contentView.addView()
    row3 = contentView.addView()

    action = row1.addLabel(LoremIpsum.sentence(), options: ["fontSize": 20])
    subject = row2.addLabel(LoremIpsum.sentence(), options: ["fontSize": 14])
    due_date = row2.addLabel("", options: ["fontSize": 12])
    status = row3.addButton("", options: ["fontSize": 12, "color": UIColor.whiteColor()])
  }

  func styleUI() {
    due_date.textAlignment = .Right
//    status.titleLabel?.textAlignment = .Right
    if status.titleLabel!.text != nil {
      if status.titleLabel!.text == "Finished" {
        status.backgroundColor = UIColor.greenColor().darker().darker()
      } else {
        status.backgroundColor = UIColor.redColor().lighter()
      }
    }
    status.layer.cornerRadius = 2
    status.clipsToBounds = true
    status.contentEdgeInsets = UIEdgeInsets(top: 2, left: 5, bottom: 2, right: 5)
  }

  override func setSelected(selected: Bool, animated: Bool) {
    super.setSelected(selected, animated: animated)
  }

  override func updateConstraints() {
    super.updateConstraints()
//    println(__FUNCTION__)

    row1.alignToTop()
    row2.isBelowTo(row1, options: ["offset": 0])
    row3.isBelowTo(row2, options: ["offset": 5])

    action.alignToLeading()

    subject.alignToLeading()
    due_date.isRightOf(subject)
    due_date.autoSetDimension(.Width, toSize: 120)
    due_date.autoPinEdgeToSuperviewMargin(.Trailing)

    status.alignToTrailing()
  }

  required init(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
}