ASTableNode

ASTableNode is equivalent to UIKit’s UITableView and can be used in place of any UITableView.

ASTableNode replaces UITableView’s required method

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell

with your choice of one of the following methods

Swift Objective-C

- (ASCellNode *)tableNode:(ASTableNode *)tableNode nodeForRowAtIndexPath:(NSIndexPath *)indexPath

func tableNode(_ tableNode: ASTableNode, nodeForRowAt indexPath: IndexPath) -> ASCellNode

Swift Objective-C

- (ASCellNodeBlock)tableNode:(ASTableNode *)tableNode nodeBlockForRowAtIndexPath:(NSIndexPath *)indexPath

func tableNode(_ tableNode: ASTableNode, nodeBlockForRowAt indexPath: IndexPath) -> ASCellNodeBlock

It is recommended that you use the node block version of these methods so that your table node will be able to prepare and display all of its cells concurrently. This means that all subnode initialization methods can be run in the background. Make sure to keep 'em thread safe.

These two methods, need to return either an ASCellNode or an ASCellNodeBlock. An ASCellNodeBlock is a block that creates a ASCellNode which can be run on a background thread. Note that ASCellNodes are used by ASTableNode, ASCollectionNode and ASPagerNode.

Note that neither of these methods require a reuse mechanism.

Replacing UITableViewController with ASDKViewController

Texture does not offer an equivalent to UITableViewController. Instead, use an ASDKViewController initialized with an ASTableNode.

Consider, again, the ASDKViewController subclass - PhotoFeedNodeController - from the ASDKgram sample app that uses a table node as its managed node.

An ASTableNode is assigned to be managed by an ASDKViewController in its -initWithNode: designated initializer method.

Swift Objective-C

- (instancetype)init
{
    _tableNode = [[ASTableNode alloc] initWithStyle:UITableViewStylePlain];
    self = [super initWithNode:_tableNode];
    
    if (self) {
      _tableNode.dataSource = self;
      _tableNode.delegate = self;
    }
    
    return self;
}

init(models: [Model]) {
    let tableNode = ASTableNode(style: .plain)

    super.init(node: tableNode)

    self.models = models  
    self.tableNode = tableNode
    self.tableNode.dataSource = self
    
    return self
}

Node Block Thread Safety Warning

It is very important that node blocks be thread-safe. One aspect of that is ensuring that the data model is accessed outside of the node block. Therefore, it is unlikely that you should need to use the index inside of the block.

Consider the following -tableNode:nodeBlockForRowAtIndexPath: method from the PhotoFeedNodeController.m file in the ASDKgram sample app.

Swift Objective-C

- (ASCellNodeBlock)tableNode:(ASTableNode *)tableNode nodeBlockForRowAtIndexPath:(NSIndexPath *)indexPath
{
    PhotoModel *photoModel = [_photoFeed objectAtIndex:indexPath.row];
    
    // this may be executed on a background thread - it is important to make sure it is thread safe
    ASCellNode *(^cellNodeBlock)() = ^ASCellNode *() {
        PhotoCellNode *cellNode = [[PhotoCellNode alloc] initWithPhoto:photoModel];
        cellNode.delegate = self;
        return cellNode;
    };
    
    return cellNodeBlock;
}

func tableNode(_ tableNode: ASTableNode, nodeBlockForRowAt indexPath: IndexPath) -> ASCellNodeBlock {
  guard photoFeed.count > indexPath.row else { return { ASCellNode() } }
    
  let photoModel = photoFeed[indexPath.row]
    
  // this may be executed on a background thread - it is important to make sure it is thread safe
  let cellNodeBlock = { () -> ASCellNode in
    let cellNode = PhotoCellNode(photo: photoModel)
    cellNode.delegate = self
    return cellNode
  }
    
  return cellNodeBlock
}

In the example above, you can see how the index is used to access the photo model before creating the node block.

Accessing the ASTableView

If you’ve used previous versions of Texture, you’ll notice that ASTableView has been removed in favor of ASTableNode.

ASTableView, an actual UITableView subclass, is still used internally by ASTableNode. While it should not be created directly, it can still be used directly by accessing the .view property of an ASTableNode. Don't forget that a node's view or layer property should only be accessed after -viewDidLoad or -didLoad, respectively, have been called.

For example, you may want to set a table’s separator style property. This can be done by accessing the table node’s view in the -viewDidLoad: method as seen in the example below.

Swift Objective-C

- (void)viewDidLoad
{
  [super viewDidLoad];
  
  _tableNode.view.allowsSelection = NO;
  _tableNode.view.separatorStyle = UITableViewCellSeparatorStyleNone;
  _tableNode.view.leadingScreensForBatching = 3.0;  // default is 2.0
}

override func viewDidLoad() {
  super.viewDidLoad()

  tableNode.view.allowsSelection = false
  tableNode.view.separatorStyle = .none
  tableNode.view.leadingScreensForBatching = 3.0  // default is 2.0
}

Table Row Height

An important thing to notice is that ASTableNode does not provide an equivalent to UITableView’s -tableView:heightForRowAtIndexPath:.

This is because nodes are responsible for determining their own height based on the provided constraints. This means you no longer have to write code to determine this detail at the view controller level.

A node defines its height by way of the layoutSpec returned in the -layoutSpecThatFits: method. All nodes given a constrained size are able to calculate their desired size.

By default, a ASTableNode provides its cells with a size range constraint where the minimum width is the tableNode's width and a minimum height is 0. The maximum width is also the tableNode's width but the maximum height is FLT_MAX.

This is all to say, a `tableNode`'s cells will always fill the full width of the `tableNode`, but their height is flexible making self-sizing cells something that happens automatically.

If you call -setNeedsLayout on an ASCellNode, it will automatically perform another layout pass and if its overall desired size has changed, the table will be informed and will update itself.

This is different from UIKit where normally you would have to call reload row / item. This saves tons of code, check out the ASDKgram sample app to see side by side implementations of an UITableView and ASTableNode implemented social media feed.

Sample Apps using ASTableNode

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