John Regner @johnregner - Tumblr Blog

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The official name is “Navigate to Related Items” but to me, it’s the four block wonder, a menu button that sits at the top left of the Xcode

Set the cursor on a type, and you can view or navigate its superclass, subclasses, or siblings, as well as the protocols, extensions, and categories it connects to 🥳🚀

Choosing to cultivate a path as a technical leader.

I mean Object-Oriented Programming as the loosely-defined bucket in which I can put all the ills of software that I’m claiming are solved by Haskell

Really good rundown of iOS layout and drawing

Gitmoji is an emoji guide for your commit messages. Aims to be a standarization cheatsheet for using emojis on GitHub's commit messages.

This made me 😃

Person one: I almost never go to meet ups or participate in community stuff because it's so awesome working here. Me: Awesome, I could really use some mentorship to help me get to the next level. Person Two: You should do some open source work to get some mentor ship. ... no job offer 😐

I have been working on HackerRank challenges recently. Most of questions require me to read input at the beginning. Input is usually read from standard input...

A great primer on handling input from the command line.

iOS Continuous Integration Options

I want to distribute builds to my team, and others

Buddy build is your friend here. buddybuild is a great solution for getting you app built and in the hands of your team and testers. You literally just point it at your git repo, give it a certificate and you're done. Every time you make a new PR or merge to master you'll get a new build. You can have that build automatically emailed to your team or testers.

They also have integrations for crash reporting and user feedback. Even if this is not the right solution for you, it may be worth just setting up nightly builds, to distribute to your team. It is so easy to set up.

I want my build steps well documented, and flexible

Probably you'll want to start with fastlane. fastlane is basically a suite of composable tools for everything. Starting with building and testing all the way through submission to the app store and automating you app store screenshots.

Your future team will probably have a cursory knowledge of how this works which will help in the long run.

Notice I did not really talk about CI in the last one

So now that you have your fastlane scripts which can build, test , upload, your app in one go. Let's run it on CI. Since this is just a script you could really run it anywhere, Jenkins, CircleCI, or my favorite, bitrise.io.

Bitrise is just another amazing place on the internet to make a build. This is probably the route I would go if I were setting up a solution for a team. fastlane + bitrise.

They have a bunch of cool integrations for managing your Cocoapods, and Carthage dependencies, making you builds from Xcode, and all that stuff... but you won't need it because your fastlane is already configured to do all that for you. (And it lives under version control in your project.)

Why else is bitrise my fav

They have a free plan. All of their code is open source, the have great support, and it's pretty easy to get setup. (Also I tried to get TravisCI working but never could.)

Hope this helps

While I'm not a CI Expert I have spent a fair bit of time trying this stuff out and configuring it on a few of my projects. If you don't want to set this up yourself. Let me know I'd love to do some contracting work for you.

keybase-gpg-github - Step-by-step guide on how to create a GPG key on keybase.io, adding it to a local GPG setup and use it with Git and GitHub.

🤔 Why the dip for 6-9 years?

Checkout the GitTower Developer Survey

A community-driven weekly newsletter about Swift.org

I was mentioned in the Swift Weekly Brief Newsletter!

Questions I'm asking in interviews in favorite, interviewing ...

In a fit of "open source your interview process" ... list of questions I'm drawing from when interviewing. ... I thought I'd consolidate them here so they don't get lost ...

Functional Alert Actions

I have known about function currying since shortly after Swift's introduction. Also that all methods are really curried class functions. thoughtbot's JSON parsing library Argo makes extensive use of this feature too. I have never found a use for it in my own code ... until now. But first some background.

Trailing Closures

Lots of methods in Swift accept a trailing closure or function. Anywhere you see someAmazingFunction(name: String, handler: (Type -> OtherType)), the handler: can take a closure, or a function name that has the same type and number of inputs and outputs. Let's see an example.

UIAlertAction(title: String?, style: UIAlertActionStyle, handler: ((UIAlertAction) -> Void)?)

Usually we see that handler written as a trailing closure and the closure capturing or closing over (this is why they are "closures") all needed local or instance variables leading to a bit of a mess.

private func didTapRemoveDay(dayIndex: DayIndex, tripUUID: TripUUID) { let alert = UIAlertController(title: "Delete this whole day?", message: nil, preferredStyle: .ActionSheet) alert.addAction(UIAlertAction(title: "Delete", style: .Destructive){ [weak self] action in guard let blockSelf = self else { return } let op = UpdateModelOperation { ctx in guard let trip = TripDraft.withUUID(blockSelf.tripUUID, context: ctx) else { return NSError(defaultWithUserMessageKey: "Failed to Delete Day.") } let tripDayMetadata = trip.tripDayMetadatas.filter { $0.dayIndex == blockSelf.dayIndex } tripDayMetadata.forEach(ctx.deleteObject) let scenesFromDay = trip.scenes.filter { $0.dayIndex == blockSelf.dayIndex } scenesFromDay.forEach(ctx.deleteObject) let mapItems = trip.mapItems.filter { $0.dayIndex == blockSelf.dayIndex } mapItems.forEach(ctx.deleteObject) return nil } op.name = "Delete Trip Day. DayIndex: \(blockSelf.dayIndex)," + "tripUUID: \(blockSelf.tripUUID)" UIOperationQueue.shared.addOperation(op) Analytics.track(.EditTripRemoveDayTapped) }) alert.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: nil)) self.presentViewController(alert, animated: true, completion: nil) }

Now this is sorta, maybe, kinda, OK because my example is not that long and does not do too much. It can get pretty hard to read if the closures do anything non trivial. It's hard or impossible to test. Plus there is the whole weak self dance, just not my favorite. How can we clean this up? The handler signature needs to be ((UIAlertAction) -> Void)? but in since all my deletions use the same alert, how will I know which one to delete? I can't just make a method like:

func deleteThing(action: UIAlertAction) { //Void is implicit here db.deleteFromStore(itemToDelete) // <- NOPE! itemToDelete Is Not Defined updateUI() }

How do we capture the variables we need while still matching the UIAlertAction -> Void signature.

Sweet, Sweet, Curry

In order for our deletion to happen, we need the object to delete and a thing matching the action handler syntax. We will just make a function that returns a function. Instead of closing over the variables we need we will pass them in. Once they are bound to the function we will return a function that matches the required syntax.

When I wrote this I did it in two steps to help my understanding (returning function is not natural for me yet).

Write the function we need:

func deleteThing(itemToDelete: ObjectType) { db.deleteFromStore(itemToDelete) updateUI() }

Now update it to match the curried signature we need:

func deleteThing(itemToDelete: ObjectType) -> (UIAlertAction) -> Void { db.deleteFromStore(itemToDelete) updateUI() }

Then fix it so it compiles. We need to return a function which takes an action and returns void. So drop a little return { action in in there.

func deleteThing(itemToDelete: ObjectType) -> (UIAlertAction) -> Void { return { alert in db.deleteFromStore(itemToDelete) updateUI() } }

Clean up our first example

We just have to replace our trailing closure with a function call that captures the state we need.

private func didTapRemoveDay(dayIndex: DayIndex, tripUUID: TripUUID) { let alert = UIAlertController(title: "Delete this whole day?", message: nil, preferredStyle: .ActionSheet) let deleteAction = UIAlertAction(title: "Delete", style: .Destructive, handler: delete(dayIndex, fromTrip: tripUUID)) let cancel = UIAlertAction(title: "Cancel", style: .Cancel, handler: nil) alert.addAction(deleteAction) alert.addAction(cancel) self.presentViewController(alert, animated: true, completion: nil) } func delete(dayIndex: DayIndex, fromTrip tripUUID: TripUUID) -> ((UIAlertAction) -> Void) { return { action in let op = UpdateModelOperation { ctx in guard let trip = TripDraft.withUUID(tripUUID, context: ctx) else { return NSError(defaultWithUserMessageKey: "Failed to Delete Day.") } let tripDayMetadata = trip.tripDayMetadatas.filter { $0.dayIndex == dayIndex } tripDayMetadata.forEach(ctx.deleteObject) let scenesFromDay = trip.scenes.filter { $0.dayIndex == dayIndex } scenesFromDay.forEach(ctx.deleteObject) let mapItems = trip.mapItems.filter { $0.dayIndex == dayIndex } mapItems.forEach(ctx.deleteObject) return nil } op.name = "Delete Trip Day. DayIndex: \(dayIndex), tripUUID: \(tripUUID)" UIOperationQueue.shared.addOperation(op) Analytics.track(.EditTripRemoveDayTapped) } }

This feels a lot easier to read and is easier to test too. And now we can see that the main meat of this is just model update NSOperation stuff, and probably does not belong in our view controller.

#Swift #functional programming

Prevent First Responder Orphans

I recently had an interesting bug report / feature request. When editing an item in a table view with multiple editable items you can can easily scroll away from it and forget what the keyboard is editing.

A good solution to this issue is to end editing when the first responder goes off screen. You could keep a reference to the currently editing cell, then resign first responder when that cell goes off screen. I try to avoid this type of "state management" when possible.

We want the cell to endEditing when it goes off screen. We don't want to keep track of which cell is editing. We know the editing cell is currently the first responder, so how do we get a reference to the first responder? Through some magic, that's how.

Finding The First Responder

UIApplication has a function for sending "Target -> Action" messages. We are going to use that. Checking the docs for UIApplication.sendAction(_:to:from:forEvent) shows that if the target is nil this action is delivered to the firstResponder.

So we will send the first responder a message:

UIApplication.sharedApplication().sendAction("message:", to: nil, from: nil, forEvent: nil)

OK cool we can send message: to the first responder, but what should our function do. We need the first responder to receive this message and then do something? probably return self so that we can get a reference to it.

We also want this function to be callable from anywhere so we will make it a class function on UIResponder. It should also return us a responder so that we can end editing on that responder. Now that we can find and message the first responder. We need a reference to it, so we can determine its frame and detect whether it is still on screen.

extension UIResponder { private static weak var currentResponder: UIResponder? = nil class func findFirstResponder() -> UIResponder? { currentResponder = nil UIApplication.sharedApplication().sendAction("saveSelf:", to: nil, from: nil, forEvent: nil) return currentResponder } func saveSelf() { UIResponder.currentResponder = self } }

OK so digging through the code above: findFirstResponder() needs to return an optional because you don't always have a first responder. We need to use sendAction to the UIApplication so that our message gets passed on to the first responder. Our saveSelf() function is pretty much as easy as could be. To tie it all up, we need to set the previous responder to nil, before fetching a new first responder, (in case it's nil) then return the found first responder. Finally we will make our currrentResponder storage weak since, someone else is certainly holding a reference to it already, the super view, the view controller ... we don't need it to stick around, plus it's optional so we will handle it with care anyway.

When to dismiss

"When the text field goes off screen" How do we know when it goes off screen?

The UITextField is in a scroll view. So we can just compare the frame of the text field with the scroll view's content offset to see if it is still on screen. Since the table view is a subclass of scroll view we can set ourselves as the scrollViewDelegate and use those call backs to determine when to dismiss our first responder. (actually UITableViewDelegate conforms to UIScrollViewDelegate so we don't need to declare any new conformance if already conforming to UITableViewDelegate) scrollViewDidScroll looks promising but gets called on every frame and may have performance implications. What about scrollViewDidEndDragging:withDecelerate: is pretty promising but gets called when the users finger lifts after scrolling, how do we know where the screen will stop after it decelerates. The method we really want to use is

scrollViewWillEndDragging(scrollView:withVelocity:targetContentOffset:)

This method is amazing. It tells you where the scroll view will be when the animation finishes. This is the one we will use.

Here is the completed method.

override func scrollViewWillEndDragging(scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) { guard let firstResponder = UIResponder.findFirstResponder() as? UIView else { return } // 1 let offset = targetContentOffset.memory.y // Get the final Y offset // 2 let rectInScrollView = scrollView.convertRect(firstResponder.bounds, fromView: firstResponder) //3 let scrollViewFutureOrigin = CGPoint(x: scrollView.contentOffset.x, y: offset) let scrollViewFutureBounds = CGRect(origin: scrollViewFutureOrigin, size: scrollView.bounds.size) // 4 if !scrollViewFutureBounds.contains(rectInScrollView) { firstResponder.endEditing(true) } }

Line 1 gets the final resting offset off the scroll view. We need to reach through the memory because the value is in an UnsafeMutablePointer. Line 2 was a bit confusing to me even after the first time I had written it. Remember bounds is always in the view's own coordinate system, so origin is almost always (0,0), and the frame has the origin in the superview's coordinates system. However, what we really want is to have the frame of the first responder in the scroll Views coordinate system. We can get this with the convertRect method. This will let us know where our first responder sits inside of the scroll view, then we can figure out if it is still on screen.

Line 3 is where we finally put this new amazing offset to good use. We can determine what part of the scroll view's content will be visible when the scroll animation ends by building a CGRect using the scroll view's current parts and replacing the y offset with our new offset. Finally on Line 4 we check if the scroll view's visible region contains our first responder.

Closing

I put a small sample project on github.com/regnerjr/DismissKeyboardByScrolling. Thanks.

When writing code, I generally like to use a dark theme in my IDE or text editor. For Xcode, I really like the Tomorrow Night and Seti themes in particular (both of which can be easily installed us…

Awesome!

Music Recommendations

My recent Jams

Really been digging this playlist the last few weeks

FuNkST on Spotifiy

Table View Simple Multi Selection

UPDATE

Thanks to @bnkohrn on twitter I was alerted to the fact that you can simply configure this in the storyboard. Just edit the tableView's attributes to declare that the tableView allows multiple selection when editing. I have also update the github project linked below to demonstrate this far superior method. Thanks again Nick!

TableView Multiple Selection with Amazing Check Marks

You have a project and maybe you are adding some filtering or user selection to a big data set. You start with the most straightforward thing. You probably use a picker view. But soon your app gets a bit fancier and you want to put in multiple selection.

You've probably seen this done wit some fancy animated check-boxes, or custom views, or maybe the most simple way just the grey highlight on the cell itself.

We learned yesterday at my Sunday iOS study group that there is a built in interaction in iOS that will let you select multiple rows in a table view, with a great looking check-mark pretty easily.

First you need UITableView. Just drop it in your view controller, connect up the appropriate delegate methods, and fill it with some data.

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource { @IBOutlet weak var tableView: UITableView! var data = (1...100).map { String($0) } override func viewDidLoad() { super.viewDidLoad() tableView.setEditing(true, animated: false) } func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return data.count } func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell { let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) cell.textLabel?.text = data[indexPath.row] return cell } func tableView(tableView: UITableView, editingStyleForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCellEditingStyle { return UITableViewCellEditingStyle.init(rawValue: 3)! } }

There are a few things to note: I am using a storyboard. The storyboard has one prototype cell, with only the default properties, and a "Cell" reuse identifier. The tableView must be in editing mode, note the tableView.setEditing(true, animated: false). Also take note that all of this magic is enabled by the editingStyleForRowAtIndexPath delegate method. The documentation shows .None, .Delete, or .Insert, and we are using the undeclared 4th option.

The code is available on Github iOS Connect

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John Regner