Home iOS & Swift Books UIKit Apprentice

32
Search Bar Written by Matthijs Hollemans & Fahim Farook

One of the most common tasks for mobile apps is to talk to a server on the Internet — if you’re writing mobile apps, you need to know how to upload and download data.

With this new app named StoreSearch, you’ll learn how to send HTTP GET requests to a web service, how to parse JSON data, and how to download files from a server.

You’re going to build an app that lets you search the iTunes store. Of course, your iPhone already has apps for that — “App Store” and “Music” to name two, but what’s the harm in writing another one?

Apple has made a web service available for searching the entire iTunes store and you’ll be using that to learn about networking.

The finished app will look like this:

The finished StoreSearch app
The finished StoreSearch app

You will add search capability to your old friend, the table view. There is an animated pop-up with extra information when you tap an item in the table. And when you flip the iPhone over to landscape, the layout of the app completely changes to show the search results in a different way.

With the last app, you dipped your toe in the dark mode pool. Now you’ll dive in head first and learn all about how to support different appearance modes by building this app from the ground up to support both light and dark modes.

There will also be an iPad version of the app with a custom UI for the iPad:

The app on the iPad
The app on the iPad

StoreSearch fills in the missing pieces and rounds off the knowledge you have gained from developing the previous apps. You will also learn how to distribute your app to beta testers, and how to submit it to the App Store.

In this chapter, you will do the following:

  • Create the project: Create a new project for your new app. Set up version control using Git.
  • Create the UI: Create the user interface for StoreSearch.
  • Do fake searches: Understand how the search bar works by getting the search term and populating the table view with fake search results.
  • Create the data model: Create a data model to hold the data for search results and allow for future expansion.
  • No data found: Handle “no data” situations when doing a search.

There’s a lot of work ahead, so let’s get started!

Create the project

Fire up Xcode and make a new project. Choose the App template and fill in the options as follows:

  • Product Name: StoreSearch
  • Team: Default value
  • Organization Identifier: com.yourname
  • Interface: Storyboard
  • Life Cycle: UIKit App Delegate
  • Language: Swift
  • Use Core Data, Include Tests: leave these unchecked

When you save the project Xcode gives you the option to create a Git repository. You’ve ignored this option thus far, but now you should enable it:

Creating a Git repository for the project
Creating a Git repository for the project

If you don’t see this option, click the Options button at the bottom-left of the dialog.

Git and version control

Git is a version control system — it allows you to make snapshots of your work so you can always go back later and see a history of the changes made to the project. Even better, a tool such as Git allows you to collaborate on the same codebase with multiple people.

The first screen

The first screen in StoreSearch will have a table view with a search bar — let’s create the view controller for that screen.

Test dark mode

Since we are building the app for both appearance modes from the ground up, we should test each screen for both appearance modes each time we do any testing.

The Xcode environment overrides
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Git version control

Notice that the project navigator now shows M and R icons next to some of the filenames in the list:

Xcode shows the files that are modified
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The history of commits for this project
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Xcode shows the changes you’ve made since the last commit
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Your commit is listed in the project history
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Create the UI

StoreSearch still doesn’t do much yet. In this section, you’ll build the UI to look like this — a search bar on top of a table view:

The app with a search bar and table view
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UITableViewController vs. UIViewController

So what exactly is the difference between a table view controller and a regular view controller?

Set up the storyboard

➤ Open the storyboard and use the View as: panel to switch to the iPhone SE (2nd generation). It doesn’t really matter which iPhone model you choose here, but the iPhone SE makes it easiest to follow along with this book.

Creating constraints to pin the Table View
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Search Bar must be below of Table View (left), not inside (right)
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The constraints for the Search Bar
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The search view controller with Search Bar and Table View
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Connect to outlets

You know what’s coming next — connecting the Search Bar and the Table View to outlets on the view controller.

@IBOutlet var searchBar: UISearchBar!
@IBOutlet var tableView: UITableView!

Table view content insets

If you run the app now, you’ll notice a small problem: the first rows of the Table View are hidden beneath the Search Bar.

The first row is only partially visible
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tableView.contentInset = UIEdgeInsets(top: 56, left: 0, bottom: 0, right: 0)

Do fake searches

Before you implement the iTunes store searching, it’s good to understand how the UISearchBar component works.

Add a search bar delegate

➤ Add the following to the bottom of SearchViewController.swift, after the final closing bracket:

// MARK: - Search Bar Delegate
extension SearchViewController: UISearchBarDelegate {
  func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
    print("The search text is: '\(searchBar.text!)'")
  }
}

Show fake results

➤ Add the following new (and empty) extension to SearchViewController.swift:

// MARK: - Table View Delegate
extension SearchViewController: UITableViewDelegate, UITableViewDataSource {
}
extension SearchViewController: UITableViewDelegate, UITableViewDataSource {
  func tableView(
    _ tableView: UITableView, 
    numberOfRowsInSection section: Int
  ) -> Int {
    return 0
  }
  
  func tableView(
    _ tableView: UITableView,
    cellForRowAt indexPath: IndexPath
  ) -> UITableViewCell {
    return UITableViewCell()
  }
}
The connections from Search View Controller to the other objects
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var searchResults = [String]()
func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
  searchResults = []
  for i in 0...2 {
    searchResults.append(
      String(
        format: "Fake Result %d for '%@'", i, searchBar.text!
      )
    )
  }
  tableView.reloadData()
}
func tableView(
  _ tableView: UITableView, 
  numberOfRowsInSection section: Int
) -> Int {
  return searchResults.count
}

func tableView(
  _ tableView: UITableView, 
  cellForRowAt indexPath: IndexPath
) -> UITableViewCell {
  let cellIdentifier = "SearchResultCell"
  
  var cell: UITableViewCell! = tableView.dequeueReusableCell(
    withIdentifier: cellIdentifier) 
  if cell == nil {
    cell = UITableViewCell(
      style: .default, reuseIdentifier: cellIdentifier)
  }
  cell.textLabel!.text = searchResults[indexPath.row]
  return cell
}
The app shows fake results when you search
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UI Improvements

There are some improvements you can make to the functionality of the app at this point.

Dismiss keyboard on search

It’s not very nice that the keyboard stays on screen after you press the Search button. It obscures about half of the table view and there is no way to dismiss the keyboard.

searchBar.resignFirstResponder()

Extend search bar to status area

The search bar has a slightly jarring line above it to separate it from the status area – at least in Light mode. It would look a lot better if the status bar area was unified with the search bar. There’s a delegate method for UINavigationBar and UISearchBar items which allows the item to indicate its top position.

func position(for bar: UIBarPositioning) -> UIBarPosition {
  return .topAttached
}
The search bar is “attached” to the top of the screen
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The API documentation

If you were to look in the API documentation for UISearchBarDelegate you wouldn’t find the position(for:) method that you used above.

Create the data model

So far you’ve added String objects to the searchResults array, but that’s a bit limited. The search results that you’ll get back from the iTunes store include the product name, the name of the artist, a link to an image, the purchase price, and much more.

The SearchResult class

➤ Add a new file to the project using the Swift File template. Name the new class SearchResult.

class SearchResult {
  var name = ""
  var artistName = ""
}
var searchResults = [SearchResult]()
for i in 0...2 {
  let searchResult = SearchResult()
  searchResult.name = String(format: "Fake Result %d for", i)
  searchResult.artistName = searchBar.text!
  searchResults.append(searchResult)
}
func tableView(
  _ tableView: UITableView, 
  cellForRowAt indexPath: IndexPath
) -> UITableViewCell {
  . . .  
  if cell == nil {
    cell = UITableViewCell(style: .subtitle,           // change
                           reuseIdentifier: cellIdentifier)
  }
  // Replace all the code below this point
  let searchResult = searchResults[indexPath.row]
  cell.textLabel!.text = searchResult.name  
  cell.detailTextLabel!.text = searchResult.artistName
  return cell
}
Fake results in a subtitle cell
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No results found

When you add search functionality to your apps, you have to handle the following situations:

Handle not getting any results

In defense of good taste, the app will return 0 results when a user searches for “justin bieber”, just so you know the app can handle this kind of situation.

. . .
if searchBar.text! != "justin bieber" {
  for i in 0...2 {
    . . .
  }
}
. . .
if cell == nil {
  . . .
}
// New code
if searchResults.count == 0 {
  cell.textLabel!.text = "(Nothing found)"  
  cell.detailTextLabel!.text = ""
} else {
  let searchResult = searchResults[indexPath.row]
  cell.textLabel!.text = searchResult.name
  cell.detailTextLabel!.text = searchResult.artistName
}
// End of new code
return cell
func tableView(
  _ tableView: UITableView,
  numberOfRowsInSection section: Int
) -> Int {
  if searchResults.count == 0 {
    return 1
  } else {
    return searchResults.count
  }
}
One can hope…
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Handle no results when app starts

Unfortunately, the text “Nothing found” also appears initially when the user has not searched for anything yet. That’s just silly.

var hasSearched = false
func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
  . . .
  hasSearched = true      // Add this line
  tableView.reloadData()
}
func tableView(
  _ tableView: UITableView,
  numberOfRowsInSection section: Int
) -> Int {
  if !hasSearched {
    return 0
  } else if searchResults.count == 0 {
    return 1
  } else {
    return searchResults.count
  }
}

Selection handling

One more thing, if you currently tap on a row it will become selected and stay selected.

func tableView(
  _ tableView: UITableView, 
  didSelectRowAt indexPath: IndexPath
) {
  tableView.deselectRow(at: indexPath, animated: true)
}
  
func tableView(
  _ tableView: UITableView, 
  willSelectRowAt indexPath: IndexPath
) -> IndexPath? {
  if searchResults.count == 0 {
    return nil
  } else {
    return indexPath
  }
}

Code review

If you ever want to look back through your commit history, you can do that from the Source Control navigator — as you learnt how at the beginning of this chapter — or from the Code Review screen, pictured below:

Viewing code revisions
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