Session 6

splitting up is easy to do (with a split view controller)

Session Materials

• Session 6 Slides

Resources

• AutoLayouts
  • Mysteries of Auto Layout, Part 1 – WWDC 2015 – Videos – Apple Developer [Implementing UI Designs in Interface Builder
  • WWDC 2015 – Videos – Apple Developer](https://developer.apple.com/videos/play/wwdc2015/407/)
  • AstroLayout: Building Adaptive UI with Auto Layout – Objective-C
  • What’s New in Auto Layout – WWDC 2016 – Videos – Apple Developer
  • Mysteries of Auto Layout, Part 2 – WWDC 2015 – Videos – Apple Developer
• UISplitViewController
  • UISplitViewController
  • WWDC 2015 Video Session 216
  • iOS Day by Day
• iOS Concurrency
  • iOS Concurrency: Getting Started with NSOperation and Dispatch Queues
  • GCD Part 1: Ray Wenderlich
  • GCD Part 2: Ray Wenderlich
  • Swift – Concurrency, NSOperation, NSOperationQueue
• Advanced NSOperations WWDC 2015
• Crazy Swift Custom Operator
  • Custom Threading Operator in Swift
• Designated Initializers
  • iOS8 Day-by-Day :: Day 9 :: Designated Initialisers
• Adaptive Layout
  • Size classes in Interface Builder in Xcode 8
  • iOS8 Day-by-Day :: Day 7 :: Adaptive Layout and UITraitCollection
• Appearance Proxy in UIKit
  • Appearance Methods – UIAppearance Protocol Reference
  • UIAppearance – NSHipster
  • UIAppearance Tutorial: Getting Started – Ray Wenderlich
• NSUserDefaults
  • NSUserDefaults
  • Reading and writing basics: NSUserDefaults – a free Hacking with Swift tutorial
• Apple Developer Documentation
  • UIWebView
  • NSUserDefaults

Assignment

In this assignment, “Go Ask a Duck”, you will create an instant answers search engine using the DuckDuckGo Instant Answer API. The application will make use of a UISplitViewController for the application’s main interface and use NSFoundation and native Swift networking classes. This assignment will require the use of both Storyboards and programmatic interface design.

Project Setup

• Use the Master-Detail Application template provided by Xcode as the starting point for your application. You should adapt it accordingly to meet the requirements of the assignment.

Figure 1. Storyboard layout for Master-Detail Application.

• Make the application Universal by using an adaptive Storyboard.

• Use UIAppearance proxy to customize the appearance of your application in the following ways:
  • Change the color of the UINavigationBar. You can select the color.
  • Change the tint color of the UINavigationBar. You can select the color.

Figure 2. The application interface should look similar to this.

The View Controllers

MasterViewController

• The MasterViewController should have a UITableView that is filled with the results from the Duck Duck Go query.
• Include a UISearchBar in the table view’s header. You can add this in Storyboard or programatically. The search bar should provide the text for the Instant Answer API search query. This data should serve as the MasterViewController’s tableview’s dataSource.
• Use the following URL to retrieve the results in JSON format.

http://api.duckduckgo.com/?q=<QUERY TERM>&format=json&pretty=1

For example:

http://api.duckduckgo.com/?q=tesla&format=json&pretty=1

• You should used the RelatedTopics key to retrieve an array of dictionaries of the results.

• The table view should use a custom cell that displays the FirstURL and the Text field for the snippet. You will notice that the Text has an odd issue with the formatting where it appends the search term to the front of the snippet. You may optionally (it is not required), use the text in the Result field and strip out the HTML portion using some Swift string processing:

// The result from DDG
let result = "<a href=\"https://duckduckgo.com/Apple\">Apple</a>A deciduous tree in the rose family best known for its sweet, pomaceous fruit, the apple."

// Use componentsSeparatedByString to split the string.
let text = result.componentsSeparatedByString("</a>")
let cleanSnippet = text[1]

• The table cells should use autoresizing to adjust to fit the length of the text snippet.

DetailViewController

• The DetailViewController should display the link in a UIWebView (see Figure 3) when tapping on a cell from the MasterViewController. test

Figure 3. A list of results from the Duck Duck Go Instant Answers API should show in the detail view controller. Explore the properties of `UIWebView` that allows the content to be best displayed in the view. There is one property that you can set to make sure that the page scales correctly.

• Add a toolbar that holds a Favorite This Article button. Tapping on this button should save the relevant link information to NSUserDefaults. You will need to save enough metadata about the search results to be able to load the url from the bookmarks list later on. You should save the search term as well.
• Add a UIBarButton to the navigation bar that has a segue to a BookmarkViewController. This segue should of type Present As Popoverand can be set in the Storyboard.

BookmarkViewController

• The BookmarkViewController should display a table view of links that have been selected as favorites by the user. The data source should be stored in NSUserDefaults from users interactions when previously viewing the page.

Figure 4. The BookmarkViewController should list all the user’s favorite links. The table should be editable to allow the user to delete link. Tapping on a table view cell should dismiss the view controller and load the URL in the web view.

• The table view should be editable, allowing users to delete articles from the list.

• The view controller should be displayed as a popover, which should be defined by the segue type in the DetailViewController. Set the preferredContentSize so that it is 500pt x 500pt. See Figure 5.

Figure 5. Set the attributes of the view controller using Interface Builder. You can change the size of a view controller in Storyboard by changing the Size inspector to freeform. You still need to change the size of the view controller, as this only effects what you see on the screen.

• Tapping on a article in the list should dismiss the popover view controller and load the URL into the web view. To pass back the URL to the web view, you should create a custom protocol, named DetailBookmarkDelegate that communicates with the web view. The protocol needs to define only a single methods:

protocol DetailBookmarkDelegate: class {
  func bookmarkPassedURL(url: String) -> Void
}

• Ensure that the DetailViewController conforms to this protocol.

extension DetailViewController: DetailBookmarkDelegate {
  func bookmarkPassedURL(url: String) {
    // Load the passed in URL to the webview
  }
}

• Ensure that the BookmarkViewController has a delegate property that conforms to the protocol. This provides the connection between the objects that will communicate. Note that declaring you delegate property as weak prevents a retain cycle where two objects (BookmarkViewController and DetailMasterView) have a strong reference to the object and it will never be released from memory (ie a leak).

  weak var delegate: DetailBookmarkDelegate?

Networking

• Create a singleton class named SharedNetworking that will handle your API requests. In this class, use URLSession to retrieve the RSS feed.
• Use the JSONSerialization class to process the data. Your method should use a closure based completion handler. You may (and should) adapt your networking code from previous assignments.

• Your singleton class should use the networkActivityIndicatorVisibleproperty of UIApplication to activate the system activity indicator in the status bar when a networking operation is happening.
• Anytime there is a networking operation (either from your own or from the UIWebView) you should indicate this to the user.
  • Create a custom UIView that functions as a loading screen that appears whenever UIWebView is loading content. Use UIActivityIndicator in the interface.
  • You should use the UIWebView delegate methods to monitor the loading progress (See Figure 1).

Figure 6. Add heads-up-display to indicate to the user that content is downloading.

• There may be times when the data from DuckDuckGo is not available. It could be an issue with the server or a problem of bad connectivity from a device. There are many additional reasons why this could fail, but the only think that matters is your users will not be happy. You should inform the users if the request fails so that they understand what is happening with the application.

• Present an UIAlertViewController to the user when the DuckDuckGo API request fails. The exact wording of the alert is up to you.
• There are several different points of potential failure in the networking code where this should be tested for. You do not have to differentiate the type of failure to the user, just a simple message to inform them the request did not work.

Functionality

• On the application’s very first launch, use the query “apple” so that your users have something to look at.
• Save the last query in UserDefaults and preload it the query in the MasterViewController when the application is launched to ensure that there is something loaded whenever the user uses the application.
• Save the last viewed article in UserDefaults and preload it in the UIWebView when the app is launched.
• When a user taps on an article, it should load in the web view.
• The user can save their favorite articles by tapping on the button in the toolbar.
• Tapping on the Bookmark button should present a popover style view controller with a table of favorite articles (loaded from UserDefaults. The user should be allowed to delete articles from the list.
• Tapping on article should dismiss the popover and load the article into the webview.
• The application’s UISplitViewController functionality should work correctly.
  • In portrait on a iPad, only the DetailViewController should show and display a button in the navigation bar to show the MasterViewController.
  • In landscape orientation, both view controllers should be visible.
• Add an image of a star (or similar favorite image) on the DetailViewController to let the users know they are reading a favorite article. Use Adaptive Layout techniques to ensure that the star can be seen at all times.

Grading

The application should compile with no errors or warnings and perform all described behaviors. If the app does not compile you will receive a 0. Feel free to explore additional enhancements to improve the appearance or functionality of the application.

The 11th point will be awarded for applications that implement a “Night” mode for their application. Combining many of the techniques from this assignment, you should be able to invert the color palette to make the application easier to use in a dark setting.

Figure 7. An example of day and night mode in Tweetbot 4.

• Add a button to the navigation bar in each view controller for “Night” mode. Tapping on this button should toggle the state between normal and night mode.

• If the application is in “Night” mode, the tables background color should be dark and the text a light color.

Grading

The application should compile with no errors or warnings and perform all described behaviors. If the app does not compile you will receive a 0. Feel free to explore additional enhancements to improve the appearance or functionality of the application.

Due Date

Assignment 6 is due February 20, 2017 at 5:29pm.