Why, oh Why, did Apple take away ARC just to give us Optionals!?

September 12, 2014 Leave a comment

I’m having trouble understanding optionals so here is a shot at explaining them. :)

var thisIsAnInt: Int

Simple, this is an Int variable declaration.

var couldBeAnInt: Int?

This on the other hand is an optional variable declaration.

This optional declaration doesn’t mean: “this is an int, which is optional”.

It reads more like: This is an OPTIONAL variable.  It’s a type of variable in and of itself.  Its NOT NECESSARILY an Int.  It just may or may NOT contain an Int”.

Woah!

Ok so what is it for and when do you use it.  Well that part seems simple enough:

If that variable can or could or may be nil at some point, it’s an optional.

If the variable will always have a value, it will never be nil, its NOT an optional.

Don’t be misled by this simplicity.  Some variables can start out as nil and receive a value at some point.  What then?

Well it turns out there is a sort of table, if you will:

  1. Can NEVER be nil (or if it IS, its a bug) = non-optional variable….you know, the regular kind
  2. Starts out nil but NEVER ends up nil after init (or if it is, its a bug) = implicitly unwrapped optional
  3. Nil value has meaning and is expected (if it is, its NOT a bug) = optional

Yeah, thanks for confusing me :S

Here is another way around it:

var perhapsInt: Int? //this is perhaps an Int
perhapsInt = 1 //here we assign it an int
if perhapsInt != nil { //now we check to see if its nil before using it
     let intString = String(perhapsInt!) //IF it isn't, then we can access it by using !
     println(intString)
}

you can also check for that in a different way:

var perhapsInt:Int?
perhapsInt = 1 
if let actualInt = perhapsInt {
     println(actualInt)
}

Here is the kicker:

var perhapsInt: Int?
let definiteInt = perhapsInt ?? 2
println(definiteInt) // prints 2
perhapsInt = 3
let anotherInt = perhapsInt ?? 4
println (anotherInt) // prints 3

And it gets trickier what with ?? and variable != nil.  So let’s throw everything out the window and start anew.  Let’s define a function we might actually be interested in:

Assume we have an array of locations:

let errorCodes = ["100","200","300","400", "500"]
func findErrorCode (code : String, errorCodes: [String])-> String {
for tempCode in errorCodes {
     if ( tempCode == code) {
     return code
     }
}
return ""
}

This is a function we wrote to find a particular code inside an array of possible error codes.  We call it by passing it in a code and the array of possible codes.  If we pass it a code that is NOT in the array, let’s say “700”, then the “internal if” will not evaluate to true and we must return nil.  We must return nil because otherwise, because the function is meant to return a String (the name of the matched code) && that “if block” didn’t hold true, you get a compiler error because we are not being exhaustive.  This means, if we pass the function a value that IS in the array, great, we will get a ‘return code’.  However, if we pass it a value that is NOT in the array, the function would not be returning anything.  So we NEED to return something for it to work.

We could return an emply value but consider the following.  Let’s say we wish to display that code returned in the console, via println (or plot it on a map of servers for example).  The point being that we need to do something with the returned code:

if findCode("700", errorCodes) {
	plotOnMap()
}

So how do we account for such a possibility?  We need to define the return value of the function findCode as an optional.  To do this we add this to the variable “?”.  Here is what the function would look like:

func findCode (code : String, errorCodes: [String])-> String? {
for tempCode in errorCodes {
     if ( tempCode == code) {
          return code
     }
}
return nil
}

Now we can actually return a String value, maybe, or we could be returning an Optional value.

Great, now let’s asume the plot function looks like this:

func plotOnMap (code: Int) -> () {
     println("This line of code magically plots the code on a server map :)")
}

Ok so now we can say

let receiver = findCode("200",errorCodes)
if receiver {
	plotOnMap(receiver);
}

The issue is that the value returned by findCode, is Optional.  So the value of receiver will be optional.

This is what is called “implicitly defined optional“.  We have implicitly defined receiver to be an optional because the return of the function is an optional itself.

We also have another issue, plotOnMap() takes an Int, not a String.  So we have actually defined receiver as:

let receiver: String? = findCode("400",errorCodes) // inferred type String?

Notice we have defined it as String?, not String.  This means receiver can hold a String or a nil, because its being defined as an Optional type, not a String type.

So what can we do?  We can ask it for a value only if it HAS one:

let receiver = findCode("400",errorCodes) 
if receiver {
	plotOnMap(receiver!) // We use of the ! operator to unwrap the value to String
}

This would indeed fix the problem.  You have solved the possibility of an optional in a function you wrote yourself.  But there is always the other case, values returned by functions you DIDNT write!  Ugh!  Remember I mentioned that our plotOnMap() takes an Int, and not a String?  And we are in fact unwrapping an implicitly defined variable (called receiver) into a String (cause that’s what the function returns?  Well we need to convert it into an int, which is simple in Swift, just say string.toInt().  This means we have to do this:

if let receiver = findCode("400",errorCodes) {
	plotOnMap(receiver.toInt())
}

But if you jump to definition on toInt(), you will notice that it also returns an optional.  So we would need to do something more convoluted:

if let receiver = findCode("400",errorCodes) {
	if let receiverErrorCode = receiver.toInt() {
		plotOnMap(receiverErrorCode)
	}
}

which is quite confusing.  So there is a Swift syntax which let’s you condense this into:

if let receiverErrorCode = findCode("400",errorCodes)?.toInt() {
	plotOnMap(receiverErrorCode)
}

It would be prudent just to add an else to the if to be safe :)

iOS : Swift : Blocks = Closures

September 3, 2014 Leave a comment

Closure on closures

Closure on closures

I’ve never really liked blocks in ObjC.

When Swift came out it made things more complicated for me because I’ve never really liked C either.

Finally when I had to deal with closures in Swift, well that’s just gonna piss a lot of people off!

After a few days reviewing tons of material online, and I mean TONS!  I came to understand this:

The only C-like exposure I had prior to ObjC was a little PHP.  So that allows me to understand a function, which is the equivalent of a method in ObjC:

DECLARING

func sayHello( ) {

     println(“Hello World”)

}

CALLING

sayHello( )

RESULT

Hello World

Even if you didn’t have any exposure to C or PHP or some other “not-so-friendly” language as ObjC, you can surely understand that

  1. The function is called sayHello
  2. That it takes no input-parameters because the ( ) is empty
  3. That it has no return type because it returns nothing since its missing the keyword “return” inside of it :)
  4. And that all it does, instead of returning a value, is print out Hello World

Just to clarify, let’s look at a function with a return value:

DECLARING

func sayHello () -> String {

    var result = “Hello World”

    return result

}

CALLING

var whoAreYou = sayHello()

RESULT (value of whoAreYou)

Hello World

As you can see here, we actually return a value from this function, which we can assign to a variable.  I had to assign it to a variable so that it made sense to actually return a value from a function.  

So we added an output-value to an otherwise plain vanilla function.  Now lets go for the next kind of function, plain + output + input:

DECLARING

func sayHello (friendOne:String) -> String {

    println(“Hi \(friendOne)”)

    var result = “Hello, ” + friendOne

    return result

}

CALLING

var whoAreYou = sayHello(“Marcio”)

RESULT (value of whoAreYou)

Hello, Marcio

Great!  So you’ve got functions covered:

  • Plain void functions
  • Returning output-value functions
  • Input-Paramter, returning output-value functions

CLOSURES (or blocks from ObjC)

There really is no simple way to explain it in a few words.  But the first thing that stands out from a closure or block, is that IT IS a function, yes!  But it can be passed around like a variable.  So let’s take a look:

var someVariable: String

There, we just declared a variable of type string.  Let’s declare another variable:

var someOtherVariable: ( ) -> ( ) = { }

There, we have just declared another variable, of type…? :s

Simply combine the concepts:

variable = function

And we know that a function is:

function = functionName (input-parameter) -> (Output-value) {some code}

So now say:

variable = function = functionName (input-parameter) -> (Output-value) {some code}

Now drop the middle “function” :)

variable = functionName (input-parameter) -> (Output-value) {some code}

If you don’t want the function to have a name, because you are assigning it to a variable anyway, so you can just call it by calling the variable:

variable = (input-parameter) -> (Output-value) {some code}

Hey, that looks a lot like what we had above:

var someOtherVariable: ( ) -> ( ) = { }

Cool!  So what does it all mean Basil?

The important thing is that you will use closures in Swift.  I was working with Parse SDK the other day and I ran into this in Xcode:

Get closure on Closures

Get closure on Closures

This is the first stage of Autocomplete which you may already be familiar with.  It’s telling you this:

Void saveInBackgroundWithBlock(block: PFBooleanResultBlock!(Bool, NSError!) -> Void)

You already know what this means, its just a function/method that takes a block as a parameter.  

This function returns Void, according to the left Void in that line.  

Let’s say that the method is called saveInBackgroundWithBlock ( X ) and it takes 1 parameter, X, where X is a block.

The block is defined as a variable “block:” and its called PFBooleanResultBlock!

It has 2 output-values Bool & NSError.

Now you know how to fill it in.  But wait, there’s more…if you call in the next 15 minutes :-)

But seriously, Xcode now has something new.  Check it out!  To select that method in the image above, you hit Enter.  This spits out the method signature in the Editor window and expects you to fill in the rest…THE NERVE!  Luckily, you can hit Enter again while that blue selection is highlighting the block and that will give you this:

tah dah!

Get closure on Closures

Get closure on Closures

Now that’s better!  This is Xcode’s new second stage Autocomplete.  Its telling us that the block is defined by { } and it takes 2 input-parameters and returns a Void.  That new “in” keyword serves to separate the return (which is in this case, Void) from the actual code block which follows.

So you can call closures like so:

object.saveInBackgroundWithBlock {succeeded, error in

//some code

}

OR

object.saveInBackgroundWithBlock { (succeeded, error) -> Void in

//some code

}

 OR

object.saveInBackgroundWithBlock( { (succeeded:Bool, error:NSError!) in

//some code

})

OR

object.saveInBackground( { (succeeded:Bool, error:NSError! ) -> Void in } )

OR you can assign it:

var someVar: () -> () = {              

println(“Hello World”)

}

Enjoy!

 

EDIT: In brief:

How to write or declare closures:

{ (succeeded: Bool, error: NSError?) -> Void in /* code */ }
{ (succeeded: Bool, error: NSError?) in /* code */ }
{ (succeeded, error) in /* code */ }
{ succeeded, error in /* code */ }
{ /* code using $0 for succeeded and $1 for error */ }

How to pass a closure:

object.saveInBackgroundWithBlock({ /* closure */ })
object.saveInBackgroundWithBlock() { /* closure */ }   // Only if closure is last arg
object.saveInBackgroundWithBlock { /* closure */ }     // Only if closure is only arg

iOS7 Custom Transitions

August 26, 2014 Leave a comment
iOS7 Custom Transitions

iOS7 Custom Transitions

iOS7 Series –Custom Transitions

There is a hierarchy of actors you need to visualize here.  It goes a little something like:

  1. A TransitioningDelegate
  2. An AnimatedTransitioning
  3. A ContextTransitioning

The VC you start out with and that will call the transition will adopt the first protocol, the TransitioningDelegate Protocol.  The purpose of doing so is to obtain the authority to manage the entire transition process.

You will then create a Transitioning class which we can call the Transition Manager.  This class will adopt the AnimatedTransitioning protocol.  The purpose of this protocol is to animate the transition.

The Transition Manager class receives all the necessary information from the Transitioning Context (a protocol adopted by a class you wont really see) and it sends that info to the TransitioningDelegate in order for it to call the shots.

The process itself is quite simple.  We create a Transition Manager class, which adopts the AnimatedTransitioning protocol as stated above.  Then we instantiate this class and call its methods from our initial view controller, who has adopted the TransitioningDelegate protocol in order to call the shots.  Voila, our VC calls the transition for us.

So create a subclass of NSObject and call it what you wish, I called it PinRotatingTransitionManager.  Of course make it adopt the AnimatedTransitioning protocol like so:

<UIViewControllerAnimatedTransitioning>

There are 2 methods you must implement in order to adopt this protocol.  The first one is:

//Define the transition duration

-(NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{

return 1.0;

}

As you can see this simply states how long the transition will last.  It returns a value of type NSTimeInterval and takes in the transition context.

The second method is for describing the animation and it’s a bit long so let’s go one step at a time:

//1. Get current state

UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];

UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];

CGRect sourceRect = [transitionContext initialFrameForViewController:fromVC];

First we get some values for the current state; who is our fromVC, who is our toVC and what is the relevant frame of our current, fromVC.  Remember we are transitioning between two vcs.  The one we are in is called the fromVC or initialVC or if you prefer to keep the original iOS lingo, our sourceVC.  The second one is called our toVC or finalVC or destinationVC.

We need to get a reference to both of them (basically to say THIS vc will do this and THAT vc will do that!).  And of course we need to know the frame we are starting from.

//2.Settings for the fromVC ……………………….

CGAffineTransform rotation;

rotation = CGAffineTransformMakeRotation(M_PI);

fromVC.view.frame = sourceRect;

fromVC.view.layer.anchorPoint = CGPointMake(0.5, 0.0);

fromVC.view.layer.position = CGPointMake(160.0, 0);

We create a rotation transform which will rotate anything by M_PI.  Then we set our fromVC frame to the sourceRect, we define an anchor point for it and a position for it.

//3.Insert the toVC view………………………

UIView *container = [transitionContext containerView];

[container insertSubview:toVC.view belowSubview:fromVC.view];

CGPoint final_toVC_Center = toVC.view.center;

Now we need to do something quite important…get a container view to put everything into in order to run the transition.  To that container view we must add the toVC, because the fromVC is already added for us.

//4.Insert the toVC view………………………

toVC.view.center = CGPointMake(-sourceRect.size.width, sourceRect.size.height);

toVC.view.transform = CGAffineTransformMakeRotation(M_PI/2);

Now we set the toVC’s center point and apply the transform created.

And finally we perform the animation:

//5. Animate..

[UIView animateWithDuration:1.0

delay:0.0

usingSpringWithDamping:.8

initialSpringVelocity:6.0

options:UIViewAnimationOptionCurveEaseIn

animations:^{

//Setup final params of the views

fromVC.view.transform = rotation;

toVC.view.center = final_toVC_Center;

toVC.view.transform = CGAffineTransformMakeRotation(0);

} completion:^(BOOL finished) {

//When done call completeTransition

[transitionContext completeTransition:YES];

}];

This is quite simple.  We define some parameters for the animation and call a block which applies the rotation and center etc.  Once complete we call completeTransition which is mandatory.

Now run your app and you should have a very nice transition where the fromVC slides left and the toVC rotates down into place.

 

Neat huh!

Business of iOS Apps

August 8, 2014 1 comment

iOS apps business by Santiapps.com Marcio Valenzuela

iOS apps business

I keep reading articles or watching videos of iOS businesses who made it and they share their wisdom of the Common 10 Mistakes iOS developers make. Guess what? Most of those mistakes, although they are worded as developer concepts, they are really business concepts.

Common Mistakes: Don’t need a marketing guy. Don’t need a business guy. Don’t need a business perspective. Usually worded as, I thought I would get rich quick, or Im looking for a one hit wonder, or Im a great programmer and I thought that was enough.

Well guess what, if you are going to sell something and make more than 99c for it, its gonna need a Business Plan. But don’t fret, it doesn’t mean you need an MBA to help you come up with a business plan. If you are a level headed guy-or-gal, you should be ok. You just need to know what to put down on paper. You WILL need a plan if you are going to be selling something more than lemonade :)

Its a plan, take out the word ‘business’ if you don’t want to. But just think about this, Steve Jobs wasn’t the business plan type. He wanted to run his company the way he wanted to. So they kicked him out of his own company because of that. True, they begged him to come back, but Jobs had learned a thing or two about making plans. That combination took Apple to the top.

So let’s just call it a plan, because you will jot down ideas to help you organize what you need to do. Let’s add the word operating, because it will be a hands-on kind of plan. And if you wanna get fancy, throw in the word Strategic, because it will take some key ideas to put this plan into action.

Your ‘Strategic-Operating-Plan’

You need to analyze what you have and don’t have. Did you see the movie Public Enemy with Hackman and Smith? Well, if they’re big, you’re small, they’re slow and you’re mobile. To know what you can be, you gotta know what you are right now and what you’re missing.

(SWOT)

1) Know your Strengths

2) Accept your Weaknesses

3) Spot market Opportunities

4) Identify any Threats

Once you know what you have and don’t have, you probably realize you have programming skills but no selling skills. This is typical and it sucks! Guys who invented things (engine, nuclear fission, electricity) get credit, but they don’t get the ladies! Why? Cause they don’t get the moolah! You always see pictures of Einstein and Edison dying poor. But the Presidents and CEOs of companies who make cars, weapons and electricity are sitting pretty making millions every year plus bonuses and benefits.

Its a known fact, business types will always make the money while smarties slave away in a lab somewhere. You therefore need a plan to sell whatever it is you know how to make.

(Marketing Plan)

Product: The app you created is of what type? What exactly did you make and what can it do. It might seem silly, but write it down. More importantly, have others around you look at it, use it and write down what THEY think the product is and does. Did you make something you thought was cool or did you discover a need that nobody was covering quite that well? How many products can you make in a year? What kind of products will they be, will a client pull or will you push in the App Store? Your costs will vary whether its push or pull, but they won’t be zero I can promise you that!

Price: According to the type of app you made, how should you price it? Market vs Cost. You definitely need to cover your costs. But there are different types of costs. These are things you need to identify in your Strengths and Weaknesses. Your upfront costs or initial costs might be high but you can throw them all in a pile as part of the price.

If you took out a loan for 1 year of living expenses while you code (computer, internet, Apple Membership, electric bill, water bill, food, cellular etc) and ended up with a $25,000 loan, you can’t price your app at $25,500 :). You gotta know a little bit about finance such that you spread those costs out over a long period of time. If you made 1 app that sold for $1 (net) and expect 500 downloads a month, thats about $6,000 a year. That would pay off a no-interest loan in 4.1 years. But your loan payments may only be $100 a month. Think about how many apps you think you can put out a year because with 2 apps having 500 monthly downloads, your income doubles.

Place: Where will people buy it? AppStore, website, Facebook ads, Email, word of mouth. Your costs will vary depending on where you have to sell it. True, AppStore helps you lower the cost of marketing your app but it may not be the ONLY place you have to promote your app. A client-pulled app is safer in the sense that it will let you know your income upfront and significantly reduce your costs. Depending on how you defined your app, what needs it covers and how it is priced, you will decide the right place. Tech forums are not the right place for medical apps. A highly priced app would be better off at a local expensive supermarket with a nice banner than via massive emails to your friends.

Promotion: How will you promote it? InApp? iAds? As mentioned before, will this app be push or pull? That tells you where your app will be purchased and thus where you need to push it or have it be pulled. There are many ways to promote your app but in the end you need to monitor your promotions to know which ones are working our for you and which ones aren’t. That’s how you decide where to invest more money in order to promote it.

(Inherent offsync)

This is a heavy pill to swallow. Let’s define a few the kinds of concepts we have talked about and you know are required for app selling.

1) Programmers

2) Graphic Designers

3) Business

4) Sales

Like it or not, these are 4 very different types of people.

Programmers are introverted, mathematical geeks and abstract thinkers.

Graphic Designers are free spirited, un-organized rebels.

Business people are demanding, goal oriented doers.

Sales people are social, pushy creatures that hate work. Selling is not work, its their way of life.

These are mutually exclusive human traits. Ask any psychologist. This is basically why you can’t be a one-man show. You must at least be a two-man show where one programs and the other does business. That’s how most successful businesses are spawned, grown or nurtured. That means you would have to outsource graphic design and sales. Business management and operations really need to be in sync and thus should not be separated from each other and outsourced.

Graphic design is a bit easier to outsource than business-ing and programming. Sales can be ‘pushed’ or outsourced to many platforms nowadays either web, print or digital. You must still know what those platforms are, what their potential is, monitor them and grade them to see which ones work and which ones don’t. But you MUST measure everything and question why something is working (not working) the way it is (isn’t).

I don’t want you to read off with the wrong idea. Yes you CAN make it! Its just not gonna be easy, like everything in life, if you want it to be good, you have to work at it. Don’t be shy or scared of delegating and teaming up. Make sure you cover all angles, development (programming & design), business (operations & management) and sales!

Everyone must be a salesperson if they want to succeed!

Fetching data from an iOS app – The new NSURLSession API

August 1, 2014 Leave a comment
NSURLSession vs NSURLConnection by Santiapps.com Marcio Valenzuela

NSURLSession vs NSURLConnection by Santiapps.com Marcio Valenzuela

Ok, this is gonna be short, I promise! :-)

Do you remember those apps you’ve got stored away or the ones you are working on that fetch data from the web with a NSURLConnection? Time to update them, here’s how.

Basically you have a method that calls a web fetch and is somehow signaled to use that received data to refresh a UI. If you used NSURLConnection sendAsynchronousRequest:, you have the issue that it blocks the main thread. It does carry out requests asynchronously from each other, but each request does indeed block the main thread since it is carried out in the main queue. Alternatively, you can use a long brittle bunch of API’s named NSURLConnection initWithRequest: with a set of delegate callbacks. Instead, take a look at this.

If you have:

-(void)fetchDataFromWeb{
//1. LOAD DATA FROM WEB
NSURL *stringURL = [NSURL URLWithString:@"http://www.yourserver.com/appfolder/somewebserviceURL.php"];
NSURLRequest *myRequest = [NSURLRequest requestWithURL:stringURL];
[NSURLConnection sendAsynchronousRequest:myRequest queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {

//Once data is got, load local object & fire reloadData
jsonArray = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];

//UPDATE CURRENT VIEW FIRST
[self setData];

}];
}

Replace with:

-(void)fetchDataFromWeb{
//1. LOAD DATA FROM WEB
NSURLSession *session = [NSURLSession sharedSession];
[[session dataTaskWithURL:[NSURL URLWithString:@"http://www.yourserver.com/appfolder/somewebserviceURL.php"]
completionHandler:^(NSData *data, NSURLResponse *response,
NSError *error) {
// handle response
//Once data is got, load local object & fire reloadData
jsonArray = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];

//UPDATE CURRENT VIEW FIRST
[self setData];

}] resume];
}

The most important thing to note here, is perhaps an little noticed piece of code in NSURLConnection, queue:[NSOperationQueue mainQueue].

You see, other than that, the both pieces of code do pretty much the same thing. They fetch data. NSURLConnection fetches data but it will block your main thread. This means that if you call the fetch, your app will stop or hand until the NSURLResponse is received.

You could go this route:

1. Adopt the delegate:
& create a data container NSMutableData *_responseData;

2. Call your web fetch:
// Create the request.
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.yourserver.com/appfolder/somewebserviceURL.php"]];

// Create url connection and fire request
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];

3. Get your data from the callbacks:
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
// A response has been received, this is where we initialize the instance var you created
// so that we can append data to it in the didReceiveData method
// Furthermore, this method is called each time there is a redirect so reinitializing it
// also serves to clear it
_responseData = [[NSMutableData alloc] init];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
// Append the new data to the instance variable you declared
[_responseData appendData:data];
}

- (NSCachedURLResponse *)connection:(NSURLConnection *)connection
willCacheResponse:(NSCachedURLResponse*)cachedResponse {
// Return nil to indicate not necessary to store a cached response for this connection
return nil;
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
// The request is complete and data has been received
// You can parse the stuff in your instance variable now
jsonArray = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];
//UPDATE CURRENT VIEW FIRST
[self setData];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
// The request has failed for some reason!
}

That’s a BIG block of code! And it can get tedious & brittle to maintain.

NSURLSession automatically calls the web fetch in a background thread so as to not block your main thread. How cool is that? :-) Enjoy!

Creating a Menu in SpriteKit

July 26, 2014 Leave a comment
SpriteKit Menu by Santiapps.com Marcio Valenzuela

SpriteKit Menu

Cocos2d has a easy to use CCMenu object to which you add CCMenuItems.  In SpriteKit however, you are back to UIKit objects.  This doesn’t not mean its more complicated, its just different :-).  You will need to create a UIControl such as a button or you can use SpriteKit’s SKNode to create the visual object onscreen:

SKLabelNode*  someNode = [SKLabelNode labelNodeWithFontNamed:@"Chalkduster"];
[someNode setText:@"Play Game"];
[someNode setPosition:CGPointMake(CGRectGetMidX(self.frame)+5,CGRectGetMidY(self.frame)-40)];
[self addChild: someNode];

Now you simply connect the object action to some event like so:

for (UITouch *touch in touches) {
CGPoint location = [touch locationInNode:self];

if ([someNode containsPoint:location]) {
SKTransition* present = [SKTransition revealWithDirection:SKTransitionDirectionDown duration:1];
GameScene* gameScene = [[GameScene alloc] initWithSize:CGSizeMake(1024, 768)];
[self.scene.view presentScene: someNode transition:present];

}
}

Voila!  You are DONE!

Swift Tutorial II

June 7, 2014 Leave a comment

Ok so in the first tutorial we covered let, which is the keyword for defining constants.

let thisBeAConstant = 3.141

Now we are going to cover variables, which use the var keyword like so:

var thisVariable = time

Notice 2 things about Swift:

1) We don’t use ; at the end of a line.  That’s just weird :-)

2) We don’t have to specify the type.  The type is inferred by whatever value you pass in, so:

var someString = “this is a string”

var someInteger = 5

So Swift is kinda smart.  Now let’s meet some old friends “Hao jiu bu juan”

ARRAYS

var energies = ["solar""wind""fossil", "this is a mixed array", 39]

var energies:String[] = ["solar""wind""this is a string array"]

And of course we can perform some basic operations such as:

READ

var item1 = energies[0]   // “solar”

INSERT

energies.insert(“hydro”, atIndex: 2)

MODIFY

energies[3] = “geothermal”

APPEND

energies.append(“nuclear”)

or

energies += “nuclear”

COMBINE

energies += ["biomass""hamster"]

COUNT

var lengthofArray = energies.count

LOGIC

var arrayIsEmpty = energies.isEmpty

REMOVE

energies.removeAtIndex(3)
energies.removeLast()
energies.removeAll(keepCapacity: true)
MUTATE
If we used let energies, then our array is immutable, vs if we used var energies which means its mutable.
Easy as pie.
DICTIONARIES

var energies = [

    "Solar""Thermal",
    "Photovoltaic" : "Grid",
    "Nuclear" : "Dangerous"
]
Here our keys are Solar, Photovoltaic & Nuclear.  These keys can be strings or numeric values such as integers.
Once again we can:
READ
let cheapestSolarEnergy = energies["Solar"]
COUNT
var energiesCount = energies.count
MODIFY
energies["Solar"] = “PV”
REMOVE
energies["Nuclear"] = nil;
INSERT
energies["Geo"] = “Thermal”
and of course the value of a key can be an array or another dictionary:

var typesOfEnergy =

[
    platforms["Solar"]: ["Thermal""PV""GridTied"],
    platforms["Wind"]: ["Autonomous""GridTied"],
    platforms["Nuclear"] : ["Fusion""Fission","Meltdown"]
]
and we would read it:
var type1 = typesOfEnergy["Solar"][0]
See you next time! :-)
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