If you use Core Data you can add an NSFetchedResultsControllerDelegate. Add UISearchBarDelegate and friends and you are well on your way to a 500 line fat controller that nobody wants to touch. For ViewControllerA to be a delegate of ViewControllerB it must conform to ViewControllerB’s protocol which we have to specify. This tells ViewControllerA which methods it must implement. This is because we haven’t passed any data to the DetailViewController yet. Create a view controller, and drag a UITableView into the view, as shown below.

cellforrowatindexpath swift 3

In order to do this, we will need to figure out which cell was tapped, and then pass the relevant data from that cell to the next view controller. Table views are the center of many iOS applications and have many features to customize their appearance and behavior. The sections below cover basic as well as more custom table views. @Edwurtle is right you surely forget to connect your table view to your view controller. In the storyboard you should ctrl + drag from your table view to the hello icon at the top of your view controller. Select data source and repeat and select delegate.

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FWIW, I rely on typing `tableView` and looking at the autocompletions to find delegate methods. You can even declare it as a constant, this allows the compiler to verify that it is assigned a value exactly once on each code path. Add and configure the prepare method to the CustomTableViewController file. As much as possible when dealing with optionals. However, I also don’t like creating an if let statement a thousand times.

cellforrowatindexpath swift 3

If we didn’t return empty cell and let application to crash in any case xib is missing at least we can get notified that something is wrong on our application. If you just want to return one of the two possible prototype cells then you don’t need to cast at all. Before pushing viewControllerB to navigation stack we need to tell ViewControllerB that ViewControllerA is its delegate, otherwise we will get an error. In ViewControllerB we call a message on the delegate when we pop the view controller. In this demo, we will simply display the index value in the label of the DetailViewController to prove that we know which cell was tapped. In a real application, the index could be used to pull out corresponding data from arrays or dictionaries.

App not Updated for Newer Version of Swift

In theory, cell should never be nil because my code only allows cell to be one of the identifiers above. However it still makes me nervous in terms of bad practice. Difference between scale up and scale out In Cloud Computing Please turn on JavaScript in your browser and refresh the page to view its content. To do this we will make ViewControllerA a delegate of ViewControllerB.

One of the values of the struct is VehicleType. If we need to add another phone cell, all we need to do is update our cell List. And because it returns a non-optional UITableViewCell.

cellforrowatindexpath swift 3

This allows ViewControllerB to send a message back to ViewControllerA enabling us to send data back. When I try each of the suggestions to either silence https://cryptominer.services/ the warning with @nonobjc or make it a private function the table no longer loads. Set the text of the Label within the viewDidLoad method.

In case of a custom table view cell the cell can be forced casted to the custom type. @huggie This only applies to static table views defined in interface builder. Calling super will give you the static cell that’s been set up in the xib file.

This will give us the opportunity to pass any data we need to the DetailViewController right before the segue happens. FYI. Assuming your table view is in storyboard you can hook up the data source and delegate inside storyboard instead of code. In viewDidLoad(), configure the datasource and delegate of the table view. Create outlets to the custom cell class for any view you want to configure in code. By doing so, we implicitly linked the index path to the cell class. The beauty is simply changing the location of the enum within our cell List will directly correlate with the index path shown in our tableView.

Create an Instance Variable to hold the index data that will be passed from the CustomTableViewController. I believe that renaming of Apple’s frameworks is not in the scope of swift-evolution; I think you’re supposed to file a radar. Short version is, we couldn’t find any obvious way to translate delegates, so we punted on it. Swift-evolution; I think you’re supposed to file a radar. I’m using an array of struct Vehicle for the data for the TableView.

A tip I picked up from the talk by Andy Matushak. We need to convert from our task object to the view data used by the cell. For example our task object could have an NSDate object but our view data needs a formatted and localised string to display.

Updating Cell List at Runtime

A solution I have found is to use a cellList to manage all of this. If you have not seen it I recommend spending an hour to watch the great talk Andy Matuschak gave at NSSpain on refactoring view controllers. It contains a wealth of advice on slimming a table view controller. For this React Native with Nx post I am going to tackle just one method, cellForRowAtIndexPath, with the aim to reduce cellForAtIndexPath to just four lines. We need to add a prepare method in our CustomTableViewController file. The prepare method is called right before any segue happens from that ViewController.

There are many table view methods, but the only required methods are to set the number of rows for the table view and to return the cell for each row. In iOS, it is common to use multiple cells of different classes within a tableView. This can become quite hairy since our cellForRowAtIndexPath can quickly become bloated. I have seen developers directly use the indexpath to determine which cell to dequeue. Hardcoding the indexpaths to cells not only makes the code harder to reader, but it also makes it harder to change.

We don’t want that data transformation code cluttering our view controller. In practice, a UITableViewCell is rarely appropriate for your table views. Instead, you’ll often need to create a custom cell with different subviews and custom highlight and selection effects. To create and use a custom cell, follow the steps below. Passing data forward to a view controller from another view controller. When a user taps a cell in your table view, we will often want to navigate to another view controller that contains information related to the cell that was tapped.

  • Please turn on JavaScript in your browser and refresh the page to view its content.
  • The error won’t go away until you complete Step 4 below.
  • Consider that right out of the box it is both a UITableViewDataSource and UITableViewDelegate.
  • For example our task object could have an NSDate object but our view data needs a formatted and localised string to display.
  • However, I also don’t like creating an if let statement a thousand times.
  • Create an outlet from the label in your prototype cell to your Custom Cell file.

Declare that the class implements the table view datasource and delegate protocols. Look for the class declaration at the top of your Swift or Objective-C file. Add UITableViewDataSource and UITableViewDelegate after UIViewController. Note that there will be an error that your class doesn’t implement the required UITableViewDataSource functions. The error won’t go away until you complete Step 4 below.

Create an outlet from the label in your prototype cell to your Custom Cell file. Then, in the Attribute Inspector, set the Identifier of the custom cell. Select the UITableViewCell in Storyboard and type in the name of the custom cell in the Identity Inspector. Control-drag from the view to the implementation file to create an outlet to the UITableView. I have this working in a different view controller.

There won’t be a need to change the cellForRow if it already handles that cell properly. Let say in any case xib file missing or something then this method will return an empty cell as the UITableViewCell. If that so user will see nothing and there is no way us as developer to get notified about it.

Create Dynamic and Static Table Views in Swift 3

Each section has a row, the count of sections is determined by the count of the array that populates it. The UITableViewController is a go-to class for iOS developers but seems especially prone to code bloat. Consider that right out of the box it is both a UITableViewDataSource and UITableViewDelegate.

The key principle here is that our table view cell is now working with simple, immutable value types. Our view controller only needs to set the view data and no longer needs to care about the view internals. Unfortunately it then gets lazy and reaches into our custom table view cell and directly messes with the view. We have all done it but this is straying from the path of lean and clean view controllers which leads to pain and we all know where that ends up.