TailLoadingCellNode.swift

//
//  TailLoadingCellNode.swift
//  Sample
//
//  Created by Adlai Holler on 2/1/16.
//
//  Copyright (c) 2014-present, Facebook, Inc.  All rights reserved.
//  This source code is licensed under the BSD-style license found in the
//  LICENSE file in the /ASDK-Licenses directory of this source tree. An additional
//  grant of patent rights can be found in the PATENTS file in the same directory.
//
//  Modifications to this file made after 4/13/2017 are: Copyright (c) 2017-present,
//  Pinterest, Inc.  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//

import AsyncDisplayKit
import UIKit

final class TailLoadingCellNode: ASCellNode {
  let spinner = SpinnerNode()
  let text = ASTextNode()

  override init() {
    super.init()
    
    addSubnode(text)
    text.attributedText = NSAttributedString(
      string: "Loading…",
      attributes: [
        NSFontAttributeName: UIFont.systemFont(ofSize: 12),
        NSForegroundColorAttributeName: UIColor.lightGray,
        NSKernAttributeName: -0.3
      ])
    addSubnode(spinner)
  }

  override func layoutSpecThatFits(_ constrainedSize: ASSizeRange) -> ASLayoutSpec {
    
    return ASStackLayoutSpec(
      direction: .horizontal,
      spacing: 16,
      justifyContent: .center,
      alignItems: .center,
      children: [ text, spinner ])
  }
}

final class SpinnerNode: ASDisplayNode {
  var activityIndicatorView: UIActivityIndicatorView {
    return view as! UIActivityIndicatorView
  }

  override init() {
    super.init()
    setViewBlock {
        UIActivityIndicatorView(activityIndicatorStyle: .gray)
    }
    
    // Set spinner node to default size of the activitiy indicator view
    self.style.preferredSize = CGSize(width: 20.0, height: 20.0)
  }

  override func didLoad() {
    super.didLoad()
    
    activityIndicatorView.startAnimating()
  }
}