#swift2.0

Swift 2 (Swift 2.2), Xcode7

When you’re using Xcode to make your app, you’ll see errors and warnings pop up in the gutter of your code, letting you know where problems are, or could be in the future. But sometimes we run the app in Simulator and it crashes, even if the code looks fine. Broadly speaking, this is the difference between ‘Compiler Errors’ (errors that need to be fixed before the code can be run) and ‘Runtime Errors’ (errors that occur when we are running the app).

When this happens we open our debugger. At the top right of Xcode are the buttons shaped like rectangles with lines in them, which we use to show or hide the Navigator (left) and Utilities (right). The button with the line at the bottom shows the Debug area.

When our app crashes, it should come up with an error message in the right of the debug menu. These error messages, as you’ve probably got used to with Xcode, come in a wide range of usefulness, from telling you what the problem is, to spitting out gibberish and leaving you on your own.

We’re going to cover one of those confusing errors today. Specifically a thing called an ‘Orphan Outlet’. These are reasonably common, and cause your pretty top-tier crashes, before it even seems to be touching the code that you’ve written.

It might look something like: Terminating app due to uncaught exception ’NSUnknownKeyException’, reason: [insert specific for you information here]: this class is not key value coding-compliant for the key [name of Orphaned Outlet].

So, what is an ‘Orphaned Outlet’, and why do they happen so frequently?

Well when we make things in Main.storyboard (that’s our visual app interface), we get used to making Labels and Buttons and those sorts of things, pulling up the Assistant Editor (the bit that pulls your code up alongside) and ctrl-dragging one of these elements into our code, connecting them. All well and good.

However sometimes we think, ‘Actually, I don’t need that Label connected anymore’ or ‘I don’t really need that code’ and delete the lines of code that that process added.

This creates the ‘Orphaned Outlet’, because behind the scenes it’s still all connected, and the app gets cranky when trying to put things together that aren’t in the code anymore.

How do we check for them and get rid of them then?

We can use the ‘Connection Inspector’ (6th tab in your right-hand Utilities, or alt-cmd-6) to show all of our connections when we click on each element. It will be pretty obvious if the element has a connection - it will be ringed in darker grey. These tell you what it is known as in the code e.g. myLabel, and the section it relates to, e.g. View Controller. This means you should be able to fairly easily search through your code and see if it’s used if you’re not sure.

If you find an OO, then you can delete it. This means going to that grey ring and clicking the little grey X next to the section label.

Or you can right-click (/two-finger click) on the element in your app display (e.g. main.storyboard) and do all of that from there, without the Connection Inspector. Either’s good.

If you know you’ve been doing a lot of connecting, deleting and messing around with elements, and you’re getting a confusing sounding crash, then it might be worth having a check for some ‘Orphaned Outlets’.

Swift 2.0 (Swift 2.2), Xcode7

I’m following a tutorial to make an iPhone app. But the labels don’t wrap text even when set to 0 lines and word wrap. Why isn’t it working the same as in the video?

- Me, 1 week ago.

Related to: WAS? Buttons and Labels in Wrong Place When Run

This question I actually had at the same time as the last one, and the resolution is much the same - Xcode7 seems to need more constraints than it used to.

So, how to make a label wrap onto multiple lines in Xcode7. Different from previously I gather, with the extra constraints, or else maybe the internet thought that this bit was obvious when they were saying how to fix the problem. But that’s why I’m here, to state the obvious, when frankly, I don’t think it is.

Step 1: Set your Lines to 0

Click on your label. In the ‘Attributes Inspector’ (alt-cmd-4 or in your right hand ‘Utilities’ menu, the 4th tab along at the top, like a shield shape ), in your ‘Label’ section (the top one), there will be a bit called ‘Lines’ and it will be set to a number. Set this number to 0. This will mean the app will try to wrap the text in your label when it overfills to whatever number of lines seems appropriate. If you’re not dealing with changing text you could set the number of lines manually to whatever looks right to you.

Step 2: Set Line Breaks to Word Wrap

In the same menu, keep reading down and you’ll find a section called ‘Line Breaks’. Set this to ‘Word Wrap’ and it will wrap based on the end/beginning of words. ‘Character Wrap’ would do it on individual characters, like you might see in a book sometimes with a dash and the word continuing in the next line.

Step 3: Add (More) Constraints

Without enough constraints, the app isn’t going to know when it needs to wrap text, and might continue in one line off the screen. So if it’s still not working, add extra constraints - like to the right edge of your screen, so the app knows not to go beyond it when rendering (making and putting on screen) the text.

In your Main.Storyboard (the bit where you see what your screen might look like), hold ctrl and click on the thing you want to add constraints to and then drag that point to where you want to constrain it to. So if you want a button to be so-high from the bottom edge of the screen, you ctrl-drag from the button, to the bottom edge of the screen.

Step 4: Run it and Check

Press the play button in the top left to run the simulation, or cmd-R. If it’s still not working, check you’ve done enough constraints (cover at least 3 sides), but there are other things you can try. So for example you can try setting the number of lines to a set high number that you think you’re unlikely to go over, and see if that works. You can also go into ‘Size Inspector’ (next tab along or alt-cmd-5) and set your ‘Preferred Width’ (top option) to an Explicit size - just type in the box. You can also check to see if WAS?: Changing the Size of the View Controller helps.

If you’re still having trouble, it’s probably worth asking someone directly. And remember, there are always going to be multiple ways to do this - that’s code for you, so if you find another way of doing it, then good job! And if anyone tells you there’s only one way to do pretty much anything to do with coding, they’re probably lacking imagination.

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Swift 2.0 (Swift 2.2), Xcode7

I’m following a tutorial to make an iPhone app. I’ve set the constraints as shown in the video, but the buttons and labels are still in the wrong place - too far to the left. Why isn’t it working the same as in the video?

- Me, 1 week ago

This one took a while, an the internet wasn’t too helpful. So what do we do when documentation, and the internet fails us? Well the next thing is to keep messing around with things we may not understand and see what happens. 

In this case, it seems to be a case of constraints. Now Swift-Code (Swift and/or Xcode) moves along at a reasonably ready pace - what works in a video from a year ago, might not work now, because they’re both still in that fast-paced early development when they shift things around. One of those things appears to be constraints. It seems like you needed less of them for the app to be able to guess what you meant, but now it wants a few more.

So, let’s add some more constraints.

In your Main.Storyboard (the bit where you see what your screen might look like), hold ctrl and click on the thing you want to add constraints to and then drag that point to where you want to constrain it to. So if you want a button to be so-high from the bottom edge of the screen, you ctrl-drag from the button, to the bottom edge of the screen.

I found most things needed to be constrained on at least 3 sides.

I screwed up, how do you delete a constraint in Xcode7?

Weirdly no x pops up when you click on it, or an option when you right/2-finger click on it. No, to delete a constraint, you click on the constraint in the ‘Size Inspector’ (next tab along or alt-cmd-5) and press backspace as if you were deleting some text. to remove all of them, you can go into Editor>Resolve Auto Layout Issues>Clear Constraints. Remember to make sure you’ve clicked on the right element (button label etc.) before you begin though.

If avoiding constraints, because you’re following a demo and haven’t seen them used yet, but are having the same sort of issue, see if WAS?: Changing the Size of the View Controller helps.

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Swift 2.0, (Swift 2.2), Xcode7

Labels in XCode View are positioned differently in Simulator. I’m following a tutorial and in XCode 7, on a Swift 2 project, when I place a label onto the View, why is the label centred in XCode, but in the Simulator it's shown off to the right? This is just playing at the moment, where I don't want to play with constraints just yet (to be used later).

- Me, about a month ago.

Finally getting around to writing this little annoyance up. Was working through a demo (a Team Treehouse one), and found this little discrepancy between old Xcode and Xcode7. 

Try using the 4.7 inch size view controller:

Step 1: Look in the middle left hand menu (the ‘Document Outline’), if not shown it’s under Editor>Hide Document Outline (a misnomer, clicking it will Show or Hide it).

Step 2: Click on the View Controller so it's highlighted.

Step 3: Click on the 4th tab of the right hand menu (Utilities: the Attributes Inspector). If not shown it’s under View>Utilities>Show Attributes Inspector.

Step 4: Under Simulated Metrics is a Size option to change from “Inferred” to “iPhone 4.7-inch”.

Step 5: You'll need to realign things again, but now these should look central in the View and in the Simulator.

Constraints, when you get to them, will be more helpful in this regard.

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Swift 2.0 (Swift 2.2), XCode7

I just started making my first app on Xcode, opened up the simulation and got a big black screen. Why’s Xcode simulator not working?

Once I left it and the Xcode Simulator was showing a black screen and changed to white. It still didn’t show the app or go to the size of an iPhone though.

- Me, 1 week ago.

This wasn’t too hard to find the answer for, but let’s cut through 20 minutes of searching and big words and sum up the result.

First question to ask yourself:

“What device am I running this on?”

Around the top banner of Xcode7, on the left, is a play button, a stop button, and then a long button with your app name, ‘>’ and something like “iPhone 6 Plus” next to it (if you wanted to change what device your app is being simulated on, you can simply click and hold on that button).

So where’s the issue? It all comes down to pixels, the smallest possible bits of colour that make up a screen. Have you heard the phrase “Retina Display”? This is a term that Apple made up, that means the display has a high enough resolution (that’s the number of horizontal and vertical pixels on the display), and pixel density (the amount of pixels per “measurement” e.g. cm or in.) that means that a person is unable to see the individual pixels at a normal distance. Unless you do something like drop a blob of water on the screen and look through it to magnify them. But just a drop of water, if you’re testing this, please don’t immerse it. That’s next gen.

But what’s that got to do with the price of mealworms. Well, if your screen that you’re coding on is not a similar kind of display, then Xcode is going to make that simulator super big to get all the pixels in it. Potentially meaning you’re only seeing a small corner of the actual display.

You see a black screen (going to white screen) because when an app is loading in the simulator, it shows the standard Apple iOS (iPhone/Pad etc. Operating System ) booting up screen. Black, with an Apple logo in the centre with a loading bar underneath. It changes to white when the sim iDevice opens the app - if you’re making your first App, you’ve probably just put a label or button on it so far, with a white background.

“Just tell me how to fix it already.”

Fair enough. When the Simulator’s open and has focus (is the last thing you clicked on), at the top of your computer is the menu bar, go across to Window and open its menu, go to Scale, and click one of the options. So for example, for the iPhone 6 Plus I need to have a 33% scale on my MacBook.

And you should have an iDevice about the right proportions showing everything on your screen.

Maybe some day it’ll automatically resize it so Xcode newbies like us don’t get stuck, but not today I guess.

Of course if it’s still a black screen and you have definitely opened the Simulator before and don’t have any screaming red error warnings in your code then uh… maybe we’ll get to that later.

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Swift 2.0 (2.2), Xcode7

How can you see if a value is in an array and preferably get its actual value? 

- Me, yesterday

Well, Me from yesterday, I’m glad you asked and weren’t instead stumped for several hours, nearly breaking your hand when you hit the table in frustration.

One way is to use `.contains()`.

This can tell you if the value exists in the array by returning a boolean value (true or false).

Another way to see if a value is in an array, but also get the specific value out of an array like you want, is to use `.indexOf()`.

This will return `nil` if the value searched for is not in the array, or will return the index number of the value in question. If you just want to check it’s there or not, then `contains()` is the way to go, but if you definitely want the Value, then it’s just one small step to get the value once you’ve got the index number.

So, let’s say we have an array like so:

   var fruitArray: [String] = ["Apple", "Banana", "Kiwi"]

We could test to see if the value “Apple” appears in the string. `.contains()` uses dot notation, where you put the value you’re looking for in parenthesis after it.

   fruitArray.contains(“Apple")

And `.indexOf()` works the same, like so:

   fruitArray.indexOf(“Apple")

So if we just want to do something simple like get a true/false response for if the value is in the array, we can use `.contains()`:

   var fruitArray: [String] = ["Apple", "Banana", "Kiwi"]

   fruitArray.contains("Apple")    //returns true

Of course this doesn’t allow us to actually get the value itself though - if we try to print it for example, we’ll only get `true` or `false`.

   var fruitArray: [String] = ["Apple", "Banana", "Kiwi"]

   print (fruitArray.contains(“Apple”))

   //prints true

This is where `.indexOf()` comes in handy instead. With indexOf you return the index number of the array, rather than a boolean true/false. So you can do what you like with the array’s index number you receive. Like showing its value. We can do that in the same way we would in any other array - using `array[index_number]`:

   var fruitArray: [String] = ["Apple", "Banana", "Kiwi"]

   if let fruitIndex = fruitArray.indexOf("Banana") {

   print(fruitArray[fruitIndex])

   }

   //prints ‘Banana’

Or we can do something like this, where we can use `.contains()` to search two different arrays for the same value:

   var fruitArray: [String] = ["Apple", "Banana", "Kiwi"]

   var berryArray: [String] = ["Blueberry", "Strawberry", "Banana"]

   var sneakyFruit = "Banana"

   if fruitArray.contains(sneakyFruit) && berryArray.contains(sneakyFruit) {

       print(sneakyFruit)

   }

   //prints ‘Banana’

You can use `.contains()` in a function, like this easy one for checking if the entered value is in the array:

   func fruitExists (name: String) -> Bool {

       return fruitArray.contains(name)

   }

   fruitExists("Kiwi")        //‘true’

   fruitExists("Rhubarb")     //‘false’

Or use a function with like this one using both - `.contains` to check the value exists and `.indexOf()` to then edit it:

   func shopListEdit (name: String) {

       if fruitArray.contains(name) {

          let fruitIndex = fruitArray.indexOf(name)

          fruitArray[fruitIndex!] = ("\(name) and Custard")

       }

   }

   shopListEdit("Banana")

   fruitArray                               //["Apple", "Banana and Custard", "Kiwi"]

   shopListEdit(“Rhubarb”)      

   fruitArray                             //["Apple", "Banana and Custard", "Kiwi"]

There you go, Me from yesterday, persevere and remember that no question’s too stupid to deserve an answer.

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According to Wikipedia:

“Swift is a general-purpose, multi-paradigm, compiled programming language created for iOS, OS X, watchOS, tvOS and Linux development by Apple Inc. Swift is designed to work with Apple's Cocoa and Cocoa Touch frameworks and the large body of existing Objective-C code written for Apple products.”

The answer to our question seems to be: Something complicated.

If you understood that, then this blog ain’t for you. It isn’t really for anybody specific, but rather an indexable (meaning search engines can find it) blog, for the questions that dare not speak their name - the really stupid ones.

You can call me WAS. I am a professional Asker-Of-Stupid-Questions, and I’m learning to code. 

If you ask Apple, they’ll tell you “Swift is a powerful and intuitive programming language...Writing Swift code is interactive and fun, the syntax is concise yet expressive, and apps run lightning-fast“. 

So of course what I heard was ‘Hey, look here, this is relatively easy-to-do-code’ and me with my zero coding experience just kind of barrelled on in here.

Swift code is... not the hardest thing, but far from easy. Maybe it’s intuitive if you already know how to code, but not necessarily for us non-coders. Concise expressive syntax (basically grammar for computers)? Well it’s relatively short, so concise is a yes, but if I’m supposed to know what expressive means here, then I don’t. But is it fun?

Yes. Surprisingly. BUT (and it’s a big ‘But’) only if you can work out how to actually do things with it. 

Swift’s Documentation (that’s the manual) was written by coders, for coders. There aren’t many useful but easy-to-understand examples of code, in that or online in general. Error messages from Xcode (the free program you’d probably use to write Swift) are confusing or just plain lie to you about the problem. Answers to easy questions are hard to find because most people writing Swift now, came over from a language called Objective C or otherwise and have coded for a long time. Not to mention it’s really hard to Google an answer when you don’t know all the technical jargon to explain what you mean, or to get an answer from Stack Overflow when you’re too embarrassed to admit that you don’t know what the heck they’re talking about.

So. Back to why I’m here. This is a blog where I will write down the stupid questions I have, and the answers I found to them, using as little tech-speak as possible. Lots of examples and copy-pastable code. Of course, I can’t promise my answers are the best - just that they work. If I could, then I wouldn’t have been able to ask the stupid question in the first place. But if I can spare one person a minor breakdown because they had to spend 5 hours looking up something that is apparently too stupid for anyone else on the entire internet to have asked, then I’ve hopefully done some good.

В Swift 2 для Xcode 7 ввели новое ключевое слово  @testable, которое позволяет получить доступ к внутррениим API фремворков используя следующую строчку кода:

@testable import MyFramework