More progress with the Swift example

examples/Swift/Sample/TailLoadingCellNode.swift

@@ -0,0 +1,53 @@
+//
+//  TailLoadingCellNode.swift
+//  Sample
+//
+//  Created by Adlai Holler on 2/1/16.
+//  Copyright © 2016 Facebook. All rights reserved.
+//
+
+import AsyncDisplayKit
+import UIKit
+
+final class TailLoadingCellNode: ASCellNode {
+  let spinner = SpinnerNode()
+  let text = ASTextNode()
+
+  override init() {
+    super.init()
+    addSubnode(text)
+    text.attributedString = NSAttributedString(
+      string: "Loading…",
+      attributes: [
+        NSFontAttributeName: UIFont.systemFontOfSize(12),
+        NSForegroundColorAttributeName: UIColor.lightGrayColor(),
+        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(viewBlock: { UIActivityIndicatorView(activityIndicatorStyle: .Gray) }, didLoadBlock: nil)
+    preferredFrameSize.height = 32
+  }
+
+  override func didLoad() {
+    super.didLoad()
+    activityIndicatorView.startAnimating()
+  }
+}