How to Play a Short Sound in iPhone Code

Today I am going to turn my iPhone into a Ray Gun by having it play a short laser sound. You probably have seen the many gun, laser and farting apps available on the Apple App Store. Most of these apps simply play a short sound along with some fancy graphics.

Create a View Based iPhone Application

First, create a view based iPhone application in XCode and add a button to your view that will play the sound. If you need a refresher on how to use Interface Builder to hook up controls check out my article on adding a slider control.

Add the Audio Toolbox framework

Drag in the Audio Toolbox framework into your frameworks group in XCode. Here is a video on how to quickly add frameworks in XCode if you need it: Quick Tip: Adding Frameworks Painlessly in XCode. Remember that the framework will be all one word with the .framework extension, AudioToolbox.framework.

Add a short wav file to your project

I used the website Joe’s Original Wave Files for this demo and found a nice laser sound to use. You can also buy the rights to use sounds in apps that you want to sell from websites like iStockPhoto.

iPhone Memory Debugging with NSZombie and Instruments

When your iPhone app crashes with ‘BAD ACCESS’ you’re in trouble – a memory bug where you tried to call a method on a object that was already deleted. Instruments has support for NSZombie – a feature that makes it easy to find the source of the bug by showing you a full history of every alloc, retain, release, and autorelease of the object that caused the crash! Wow. Here’s how:

Basic steps are:

1. Run in Performance tool ‘Object Allocations’
2. Stop running and set options on ObjAllocations instrument: ‘Enable NSZombie’ Detection and ‘Record Reference Counts’
3. Re-run from instruments, when it crashes, click the arrow in the popup zombie dialog
4. Open up the stack trace view and see the full memory history of the problem object
5. Wow, how awesome is that?
6. If you love this post, do me a favor and check out our Free app Focus for Facebook
7. You might also like my memory management tutorial and other posts under ‘App Development’.

Enable Zombies in Instruments

Here’s a link to the demo program: ZombieDebug Demo Project. The code we’re looking at in the video is:

Software Development for the iPhone: How to Integrate In-App Purchases

In-App Purchases is a handy thingy that you can easily add to your iPhone application to let users buy your software and additional features right from your application. Interaction with App Store is implemented by the StoreKit framework, which is shipped with iPhone 3.0 SDK for developers. 

General Information

There are three types of In-App Purchases:

• Consumables
• Non-Consumables
• Subscriptions

A consumable purchase may be effected more than once. For example, if you've ever played the game Eliminate you know that you need to restore your «energy» from time to time, when its level goes too low. The catch is that a player can either wait for three hours until the energy is replenished naturally or buy it for real money.

A non-consumable purchase can be effected only once. This kind of purchase is useful for unlocking new themes, additional levels, and so on.

A subscription can be used, as you might have guessed, for subscribing to some service. For example, you can make an iPhone application for a Web service with a Premium account that is activated, say, for a month or for a year.

You can implement In-App Purchases using either of the following two models:

• Built-in model
• Server model

The built-in model lets the user unlock some features. Usually it means that those features must already be present in the application, so that StoreKit only handles the payment for the feature. Generally, StoreKit lets you check whether the purchase was successfully effected.

The server model is more flexible and involves three entities: an iPhone application, the Apple server and our (that is the developer's) server. All new features are stored on our server, so we don't have to update the application whenever we add some new features or new software products. The model works as follows:

1. The iPhone application requests a list of products from its server.
2. The iPhone application displays the new products to the user.
3. The user buys something — or doesn't. :)
4. The iPhone application requests the purchase from the Apple server via StoreKit.
5. StoreKit delivers the reply.
6. The iPhone application forwards the reply to our server.
7. The reply is re-checked — it must be always verified whether the reply was actually received from Apple's server.
8. If everything is fine, the iPhone application downloads the new product from our server.

This article is about the built-in model.

Implementation

To demonstrate how the built-in model works I'll be using a test case, AppPurchasesExample — a simple iPhone application that has three windows. The main window, which the user can see by default, contains information about two other windows, which can be unlocked only if the user agrees to pay for that.

Step 1. Creating App ID

Go to the iPhone Developer Program Portal and click on App IDs:



Click on New App ID (in the screen's top right corner), then enter the information on your application. I've filled in the form as follows:



Apple recommends using the Reverse DNS naming convention to make a Bundle Identifier, which ensures that your identifier is unique — that might save you a lot of trouble when publishing your application. It is extremely important that you do not use the asterisk (*) in the Bundle Identifier! If you fail to follow the advice and enter com.wordpress.indiedevelop.* or something like that, In-App Purchases won't work at all!

Then you need to enable In-App Purchases for your App ID. In the App IDs list, click on your Bundle Identifier's Configure button. When a Configure App ID form appears, check the Enable In App Purchase box.

Step 2. Creating the Development profile

1. Click on Provisioning in the left column, then go to Development.
2. Click on New Profile and fill in information as needed. You can put anything into the Profile Name field (as for me, I just typed in «InAppPurchasesExample Dev»).
3. The newly created profile that appears in a list has a pending status. To make the profile available for download, either refresh the page or switch to another tab and then back.
4. You can download the profile and then install it in xCode; to do the latter, either double-click on the profile or drag and drop it on the xCode icon.

If installation is successful, Organizer opens in xCode and you see something like this:

Step 3. Creating an application in iTunes Connect

To test your In-App Purchase application, you must create it in iTunes Connect. Do it as follows:

1. Go to iTunes Connect and click on Manage Your Applications, then select Add New Application.
2. When the question «Does your product contain encryption?» appears, answer in the negative.
3. Filling in the form — giving your application name, description, version No., category, and so on — should be easy. The only difficulty may be with SKU Number, which must be unique; as for me, I entered «IAPEX» (abbreviation for In-App Purchases Example).
4. On the Upload form, select «Upload application binary later.» (The other parameters and forms are irrelevant for my example.)

Step 4. Creating In-App Purchases in iTunes Connect

1. In iTunes Connect, click on Manage Your In App Purchases, select Create New, and choose your application.
2. Select Bundle ID and fill in the information on Purchase (type, name, price, etc.). Though you can use almost anything for a Product ID, I still recommend using Reverse DNS. It is advisable to make you Product ID from you application's Bundle ID and the feature name. In my case, it looks as follows:

For my application, I created two In-App products, whose Product IDs are com.wordpress.indiedevelop.InAppPurchasesExample.f1 and com.wordpress.indiedevelop.InAppPurchasesExample.f2, both non-consumables.

Step 5. Creating a test user

To test In-App Purchases, you need to create at least one test user:

1. In iTunes Connect, select Manage Users, then select In App Purchase Test User.
2. Click on Add New User.
3. Enter the user information.

The test user's e-mail needn't be real. In my case, I created one test user:



Important note. In-App Purchase will only work if you have concluded your contract with Apple. To do that, you must enter Contact Info, Bank Info, and Tax Info.

Step 6. Programming

For my test application, I created a project framework and a User Interface:



For interacting with App Store, I recommend using the MKStoreKit framework (developed in 2009 by Mugunth Kumar), which makes handling StoreKit much easier. In addition to MKStoreKit, you need to add StoreKit.framework to your project.

In my case, I used a slightly modified MKStoreKit v. 1. To make my job easier, I added a delegate to the MKStoreManager class:

@protocol MKStoreKitDelegate @optional- (void)productAPurchased;
- (void)productBPurchased;
- (void)failed;
@end

The delegate is to receive the message «productAPurchased» when Feature 1 is purchased; «productBPurchased», when Feature 1 is purchased; and «failed», when either the customer cancels the order or the purchase fails.

MKStoreKit's main class is the MKStoreManager singleton class. Here's its declaration:

@interface MKStoreManager : NSObject<SKProductsRequestDelegate> {
    ...
}
// delegate
@property (nonatomic, retain) id<MKStoreKitDelegate> delegate;
// products available for purchase
@property (nonatomic, retain) NSMutableArray *purchasableObjects;
// factory method for Singleton
+ (MKStoreManager*)sharedManager;
// methods for feature buying
- (void) buyFeatureA;
- (void) buyFeatureB;
// methods for checking whether the feature has been purchased
+ (BOOL) featureAPurchased;
+ (BOOL) featureBPurchased;
...
@end

Here's how the class is used in my test case:

First, I specified Product IDs for each feature in the MKStoreManager.m file.

static NSString *featureAId = @"com.wordpress.indiedevelop.InAppPurchasesExample.f1";
static NSString *featureBId = @"com.wordpress.indiedevelop.InAppPurchasesExample.f2";

I also need to check whether application features have been purchased. As the main class inherits from UIViewController, it make sense to put the verification code into the viewDidLoad method:

- (void)viewDidLoad {
  [super viewDidLoad];

  [MKStoreManager sharedManager].delegate = self; // assigning the delegate for the MKStoreManager object

  if ([MKStoreManager featureAPurchased]) // if feature 1 is purchased
  {
    feature1Button.hidden = YES; // hiding the Buy Feature 1 button
    seeFeature1Button.hidden = NO; // showing the Switch To Feature 1 button
  }

  if ([MKStoreManager featureBPurchased]) // if feature 2 is purchased
  {
    feature2Button.hidden = YES; // hiding the Buy Feature 2 button
    seeFeature2Button.hidden = NO; // showing the Switch To Feature 1 button
  }
}

MKStoreKit uses NSUserDefaults for saving information on whether a product is purchased, so when the application is uninstalled, the information is lost. However, the user would not have to pay for the same feature twice as StoreKit would open access to the feature for free.

Now you need to implement the Purchase methods, which are bound to the TouchUpInside event by the following buttons:

-(IBAction)feature1ButtonPressed{
  [self showLockView]; // letting the user know about the download being done
  [[MKStoreManager sharedManager] buyFeatureA]; // sending the Buy Feature 1 message to the store
}
-(IBAction)feature2ButtonPressed{
  [self showLockView]; // letting the user know about the download being done
  [[MKStoreManager sharedManager] buyFeatureB]; // sending the Buy Feature 2 message to the store
}

Here's how I implemented the MKStoreKitDelegate delegate methods:

// feature 1 is purchased
- (void)productAPurchased{
  [self hideLockView]; // hiding the download
  feature1Button.hidden = YES; // hiding the Buy button
  seeFeature1Button.hidden = NO; // showing the Switch button
}
// feature 2 is purchased
- (void)productBPurchased{
  [self hideLockView]; // hiding the download
  feature2Button.hidden = YES; // hiding the Buy button
  seeFeature2Button.hidden = NO; // showing the Switch button
}
// the purchase either failed or was cancelled
- (void)failed{
  [self hideLockView]; // hiding the download
}

I implemented the new features as separate UIView classes controlled by UIViewController, and the switchover to those features, using UINavigationController:

// switch to feature 1
-(IBAction)seeFeature1{
  [self.navigationController pushViewController:feature1ViewController animated:YES];
}
// switch to feature 2
-(IBAction)seeFeature2{
  [self.navigationController pushViewController:feature2ViewController animated:YES];
}

When interacting with the store, you may also check its availability:

if ([SKPaymentQueue canMakePayments])
{
... // Show the store to the user
}
else
{
... // Tell the user that Purchases are unavailable
}

As you can see, everything is rather simple. All that is remaining is to compile the code and to run some tests. :)

Step 7. Testing

To test In-App Purchases you need to compile, install and run the application. Please remember the following about the testing:

1. Purchases must be tested on an actual device.
2. Before you can start the test, quit iTunes on your iPhone: Settings -> Store -> Sign Out.
3. When your test is running, you will see [Environment: sandbox] in the messages containing the offer to buy a feature, so that you know that's a test mode.
4. You must use test accounts only (see Step 5) for your testing.

Test case: InAppPurchasesExample

As a result, I've got an application that can unlock two additional windows. You can use this application as an example for implementing your own In-App Purchase projects.

Starbucks Mobile Card App – Manage Your Starbucks Card From Your iPhone

As I mentioned in a previous post, Starbucks recently introduced not one, but two iPhoneapps. I previously wrote about the store locator and product information app, called Starbucks. Now, I’m taking a look at the second app, called Mobile Card.

Starbucks Mobile Card is an app for Starbucks card holders, and allows you to manage the funds on your card. The app lets you check your card’s balance, add additional funds, review your purchase history, and even pay for purchases without using a physical card (at select locations).

When you first launch the app, you’re given the choice to sign in with your Starbucks account, or continue without an account. If you’re a Starbucks card holder, it makes sense to create an account online and register your card with your account.

Registered cards are entitled to additional savings, such as no charge on syrups and other flavorings, which can save you anywhere from 30 to 90 cents per drink, a free drink on your birthday, as well as free wifi access using your laptop at any Starbucks location.

You sign in with your Starbucks username and password, and can choose whether to remember your username or not. The nice thing about this, is you could use the Starbucks Mobile Card app on a friend’s iPhone to check your balance or reload your card, without it saving your information.

Once you sign in to your Starbucks account, the app opens to a main screen with several options to manage your card, it shows the current balance, as well as an actual image of your card. This way, if you have several cards registered, you can tell at a quick glance which one you’re managing. For me, I have a single Starbucks Product(RED) card attached to my account.

After reviewing my recent transactions, and checking my balance last night, and realizing I only had $2.55 left on my account, knowing that’s not even enough to purchase one coffee in the morning, I decided to try out the reload function.

You can choose from several common preselected amounts to refill your card with, or specify a different amount. You must use a valid major credit card (Visa, MasterCard, Discover, or American Express). Here, I’ve chosen to add $50 using my Visa card, which I’ve added as a payment type.

Starbucks Mobile Card encrypts and transmits your credit card information securely using 256-bit SSL encryption, which is pretty secure. In my mind, this app would be no less secure than using my Mac on my home wifi (which is protected with WPA-2) and transmitting my credit card through a web browser. However, use it on a public wifi network with caution.

Now, perhaps you’re concerned about having your credit card information saved in an app that anyone could access if they got ahold of your iPhone. Don’t worry, Starbucks thought of that. They’ve added a passcode protection that you can enable and use a 4-digit code (just like the standard iPhone unlock screen).

Also, Starbucks assures me that the data they store on the iPhone’s memory is encrypted and protected, and unreadable by any other app. I’m pretty sure Starbucks has the resources to hire developers that really know what they’re doing, so I feel just fine taking their word for it.

After I completed my purchase, I got a confirmation screen with a pleasant surprise – I received a $5 bonus added to my account! When I inquired about this, Starbucks told me that for a limited time, all customers who register their Starbucks card and reload using their iPhone and a Visa credit card will receive a $5 bonus the first time. Hey, that’s the amount of a latte just for using their app, you can’t argue with that!

Now my card shows a new balance, which is the previous amount, plus the $50 I just added, plus the $5 bonus I received for using the app. Sweet! Now I am ready for my morning coffee!

Mobile Card also offers what I can only imagine is a really neat way to pay, if you happen to live in an area that is part of this pilot program, which I do not. For now, only the areas of San Jose, California and Seattle, Washington are participating at this time, but Starbucks says that more areas will be added as time goes on.

At these select stores, you will be able to complete a purchase without even needing to use a physical card. This way you won’t have to carry yet another plastic card in your already-stuffed wallet or bottomless purse. When you’re ready to pay, just inform the cashier you’re paying with your iPhone, and use the Pay Now function in the app. The app displays a special barcode image that the cashier can scan, which then deducts the amount from your account.

If you are a Starbucks card holder, download this app now, register your card, and get your $5 bonus! And then, as long as you continue to use your card, you’ll be saving a little off each drink. How could you ignore that? Oh, and anyone can get a Starbucks card, as it’s not a credit card (they do have those but I don’t use one, I’d get myself in trouble!) it’s just basically like a preloaded gift card.