Swift 4, Xcode 9.2

1.Assign value to navigation controller, UIImage. Adjust size by dividing frame and Image size.

func addNavBarImage() {

        let navController = navigationController!

        let image = UIImage(named: "logo-signIn6.png") //Your logo url here
        let imageView = UIImageView(image: image)

        let bannerWidth = navController.navigationBar.frame.size.width
        let bannerHeight = navController.navigationBar.frame.size.height

        let bannerX = bannerWidth / 2 - (image?.size.width)! / 2
        let bannerY = bannerHeight / 2 - (image?.size.height)! / 2

        imageView.frame = CGRect(x: bannerX, y: bannerY, width: bannerWidth, height: bannerHeight)
        imageView.contentMode = .scaleAspectFit

        navigationItem.titleView = imageView
    }

1. Add the function addNavBarImage()right under viewDidLoad()

Note on the image asset. Before uploading, I adjusted the logo with extra margins rather than cropped at the edges.

Final result:

I’ve published this answer in Stackoverflow.

Useful reminders in Git I found here.

TLDR;

When in the process of learning Git, make a habit of following these steps:

1. git status all the time!
2. Try only to change files you really want to change.
3. git add -A is your friend.
4. Feel free to git commit -m "meaningful messages" .
5. Always git pull before doing any pushing,
   but after you have committed any changes.
6. Finally, git push the committed changes.

Your receiving the following Xcode error:

Swift Sdtlib tool error: Task failed with exit code 1

I use macOS High Sierra, Xcode 9.2: This worked for me.

1. Go to /Users/JohnAppleseed/Library/Developer/Xcode/DerivedData/
2. Moved all the files to Trash, empty the trash
3. Opened Xcode, Clean and Build.

Restarting xcode or macbook, dragging and dropping certificate in the keychain did not work for me.

1. In the storyboard, check all your Outlets in each view controller.

2. Make sure you remove the connections with yellow warnings. These are invalid outlets.

3. Check your storyboard ID in the Identity Inspector if the names are correct.

4. Check for any breakpoint in the left side of the code.

Hope this helps someone!

See my answer in Stackoverflow.

Failed to instantiate the default view controller for UIMainStoryboardFile 'Main' - 
 perhaps the designated entry point is not set?

Not appearing in the Simulator along with a black screen. I did the following in order for my app to appear in the Simulator.

1. Go to Main.storyboard.
2. Check the Is Initial View Controller under the Attributes inspector tab.

1. Go to Main.storyboard.
2. Check the Is Initial View Controller under the Attributes inspector tab.

In Github, I noticed a non-committer author.

Even though I made commits in Xcode. There was no contributions in the ‘Your Contributions` Calendar.

Solution:

Change Committer Name and Email Globally
The email address used for the commits must be associated with your GitHub account.

In the Terminal:

$ git config --global user.name "Full Name"
$ git config --global user.email "fullname@gmail.com"

See also GitHub Help: Setting your commit email address in Git

Swift 4: This should display an image in a circle for iOS.

1. Drag (ctrl + click) an IBOutlet of an image toward your code.

cornerRadius The radius to use when drawing rounded corners for the layer’s background. Animatable. https://developer.apple.com/documentation/quartzcore/calayer/1410818-cornerradius

clipsToBounds property A Boolean value that determines whether subviews are confined to the bounds of the view. https://developer.apple.com/documentation/uikit/uiview/1622415-clipstobounds

2.Inside viewDidLoad(), Use the instance property layer.cornerRadius and clipsToBounds.

profileImage.layer.cornerRadius = 50
profileImage.clipsToBounds = true

Lets start creating

January marks the beginning of “the iOS developer’s path”- my long-term path to programming mastery. It might take thousands of hours of practice, but I am enjoying it to the bitter end. I’m not normally one who discuss or share “news” designed to create outrage or sarcasm, especially not on my blog, so be rest assured there won’t be any rant post.

Most of my postings are to match Apple’s documentation and community-accepted best practices. Some are derived from books, courses and networks. This blog is mainly targeted toward iOS development, but definitely applies to Mac as well.

Here’s a ton left to do:

• Ship at least 5 iOS apps of medium size or above.
• Work and on at least 2 Health app using Objective-C, Cocoa. Show how I used these technology to solve problems in healthcare.
• Write at least 3 software design documents for non-trivial applications.
• Show how my code meets the quality objectives, as measured by code reviews, static analysis tools and/or QA reports.
• Achieve a score of at least 4 out of 5 on customer satisfaction, as measured by at least 10 replies to 360 feedback requests.
• Contribute noteworthy contributions in Github and Stackoverflow.
• Attend more conferences and boot camps this year.
• Get myself a 15" MacBook Pro with Retina display.
• Install Linux as a second OS.
• Keep on making good design (even if it’s not so good at first)
• Finish reading the pile of books on my shelf about OOP languages and Graham’s The Intellegient Investor.
• FOCUS

Ideally, my strategy of using self-liberation (will power), innate curiosity and reinforcement management (rewards or incentives) would meet with success toward the year’s end.

“To me, ideas are worth nothing unless executed. They are just a multiplier. Execution is worth millions.” — Derek Sivers