The biggest hassle in testing is setting up the [...]]]> Xcode 4 has drastically improved iPhone unit testing and Mac unit testing from my previous post, iPhone Unit Testing Explained – Part I Creating the unit testing target is easy and you can start writing test code in under 5 minutes.

The biggest hassle in testing is setting up the project correctly, and Xcode 4 makes it simple. If you read Part I, I pushed for GHUnit because of the GUI interface, but now Xcode’s built in testing is enough to get you started. If you need a GUI, add GHUnit later, but start writing your tests today, since they’re compatible with GHUnit when you decide to integrate with it.

Testing is important to start from the beginning or you will never have the motivation to write the tests unless your boss demand

Getting Started

To start writing unit tests you have two options, either create a new project with unit tests or add unit tests to an existing project.

New Project with Unit Tests

Create a new project and make sure the checkbox is enabled for unit tests.

Add Unit Tests Target to Existing Projects

Add a unit test target to your project by clicking on your Project (top left) -> Add Target (bottom middle) -> iOS -> Other -> Unit Testing Bundle.

(Optional) Share the Target and Testing Scheme

If you add a unit test target, you’ll most likely want to share your testing scheme with your team over version control (git, svn, etc.) Otherwise you’re teammates will have to setup for themselves.

Goto Editor -> Manage Schemes -> Click Shared next to the Unit Test

Adding Resources

When you want to test code or import resources like images or data files you’ll need to tell the testing target about the resources. There are two ways, you can do it when you first add the resource to the project or you can do it by editing the Build Phases for the unit test target.

Adding New Resources to the Unit Test Target

Click on File -> Add Files to “TestProject” -> Click on the checkbox on unit test target and Copy items

Adding Existing Resources to the Unit Test Target

Click on your project “TestProject” -> Build Phases -> Expand one of three (Compile Sources, Link Binary With Libraries, or Copy Bundle Resources)

Resource Paths are Different!

Many assumptions that your bundle is the main bundle will cause problems when testing. (Especially when adding tests to existing code) Look at the difference in bundles, the main bundle isn’t what you’d expect in a unit test.

NSString *mainBundlePath = [[NSBundle mainBundle] resourcePath];

NSString *directBundlePath = [[NSBundle bundleForClass:[self class]] resourcePath];

NSLog(@”Main Bundle Path: %@”, mainBundlePath);

NSLog(@”Direct Path: %@”, directBundlePath);

NSString *mainBundleResourcePath = [[NSBundle mainBundle] pathForResource:@”Frame.png” ofType:nil];

NSString *directBundleResourcePath = [[NSBundle bundleForClass:[self class]] pathForResource:@”Frame.png” ofType:nil];

NSLog(@”Main Bundle Path: %@”, mainBundleResourcePath);

NSLog(@”Direct Path: %@”, directBundleResourcePath);

Output:

Main Bundle Path: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.1.sdk/Developer/usr/bin

Direct Path: /Users/paulsolt/Library/Developer/Xcode/DerivedData/PhotoTable-dqueeqsjkjdthcbkrdzcvwifesvl/Build/Products/Debug-iphonesimulator/Unit Tests.octest

Main Bundle Path: (null)

Direct Path: /Users/paulsolt/Library/Developer/Xcode/DerivedData/PhotoTable-dqueeqsjkjdthcbkrdzcvwifesvl/Build/Products/Debug-iphonesimulator/Unit Tests.octest/Frame.png

Problem: My Unit test has a nil image, data file, etc. Why?

The unit test doesn’t use the same bundle for resources that you’re accustomed to when running an app. Therefore, the resource we’re trying to load cannot be found.  You’ll need to make changes to the code to support testing external resources (images, data files, etc). For example the following code

- (UIImage *)resizeFrameForImage:(NSString *)theImageName {

UIImage *image = [UIImage imageNamed:theImageName];

// ... do magical resize and return

return image;

}

Solution 1: Change the function parameters

Functions like these are semi-black boxes that aren’t ideal for testing. You want access to all your inputs/outputs, especially if we’re working with any kind of file resource. To fix it, just pass in the resource from the unit test, rather than having the function load it from a NSString object.

- (UIImage *)resizeFrameForImage:(UIImage *)theImage {

// ... do magical resize and return

return theImage;

}

Solution 2: Change the resource loading inside the function

If you need to load the resource in the function, you can alternatively change the way it is loaded. You need to stop using UIImage’s imageNamed: method and switch to imageWithContentsOfFile: This way you can pass in the resource with the correct path, however it’ll change logic elsewhere in your app.

- (UIImage *)resizeFrameForImage:(NSString *)theImagePath {

UIImage *image = [UIImage imageWithContentsOfFile:theImagePath];

// ... do magical resize and return

return image;

}

Solution 3: Load resources using the bundle for the current class

- (UIImage *)resizeFrameForImage:(NSString *)theImageName {

// Note: There are several ways you can write it, but make sure you include

//  the extension or you'll have trouble finding the resource

// 1. NSString *imagePath = [[NSBundle bundleForClass:[self class]] pathForResource:@"Image.png" ofType:nil];

// 2. NSString *imagePath = [[NSBundle bundleForClass:[self class]] pathForResource:@"Image" ofType:@"png"];

NSString *imagePath = [[NSBundle bundleForClass:[self class]] pathForResource:theImageName ofType:nil];

UIImage *image = [UIImage imageWithContentsOfFile:imagePath];

// ... do magical resize and return

return image;

}

My First Test

Code completion in Xcode will make writing tests easy. To test different things you’ll use the following macros:

• STAssertNotNil(Object, Description);
• STAssertEquals(Value1, Value2, Description);
• STAssertEqualObjects(Object1, Object2, Description);

Example: MyTest.m

@implementation TestImagePrintHelper

- (void)setUp

{

[super setUp];

// Set-up code here.

}

- (void)tearDown

{

// Tear-down code here.

[super tearDown];

}

- (void)testName {

NSString *testFirstName = @"Paul";

STAssertEqualObjects([person firstName], testFirstName, @"The name does not match");

}

@end

The STAssertEqualObjects macro will invoke the object’s isEqual method, make sure you write one. See the section below. If you used the STAssertEquals it will test for primitive/pointer equality, not object equality.

Testable Code

Writing testable code requires that you add some additional functions that might feel optional before you decided to start testing.

1. Create a isEqual method for your class.

Most of the time you’ll want to compare if the object is the correct object. This always requires that you write an isEqual method, otherwise you’ll be using the NSObject isEqual test and it’ll compare address pointers for the objects.

Example: Person.m

- (BOOL)isEqual:(id)other {

if (other == self) { // self equality, compare address pointers

return YES;

}

if (!other || ![other isKindOfClass:[self class]]) { 

// test not nil and is same type of class

return NO;

}

return [self isEqualToPerson: other]; // call our isEqual method for Person objects

}

- (BOOL)isEqualToPerson:(Person *) other {

BOOL value = NO;

if (self == other) { // test for self equality

value = YES;

 } elseif([[selffirstName] isEqualToString:[other firstName]] &&

[self age] == [other age]) {

// Add any other tests for instance variables (ivars) that need to be compared

value = YES;

}

return value;

}

2. Create a description method for your class.

This is what will output on the command line, rather than the objects memory address. It can be also called when you decide to print the value in a tests

Example: Person.m

- (NSString *)description {

return [NSStringstringWithFormat:@"Person Name: %@ Age: %d", [self firstName], [self age]];

}

Example: Test using the description method, and we’ll see the first name and age printed like it was formatted in our description method.

STAssertEqualObjects([personfirstName], testFirstName, @"The name does not match %@", person);

Further reading in Apple’s Unit Testing Guide is available. Now you have the basics for unit testing. The next part will provide an example project using resources and providing unit tests.

(Part III: Coming Soon)

Feature article by MD

Update: 8/31/11 Idea to App Store Slides (PDF)

http://www.youtube.com/watch?v=xkwE8BRQsAo

Artwork Evolution, my first iOS App is now available on the App Store for iPhone, iPod Touch, and iPad. It allows you to create complex abstract art with the touch of a finger. You can breed images together to create new images.

Tutorial [...]]]>

Artwork Evolution, my first iOS App is now available on the App Store for iPhone, iPod Touch, and iPad. It allows you to create complex abstract art with the touch of a finger. You can breed images together to create new images.

Artwork Evolution on iPhone 4

Tutorial Video

http://www.youtube.com/watch?v=_VZnFsnO4YY

]]> http://paulsolt.com/2011/01/artwork-evolution-on-app-store/feed/ 1 http://paulsolt.com/2010/09/ios-converting-uiimage-to-rgba8-bitmaps-and-back/ http://paulsolt.com/2010/09/ios-converting-uiimage-to-rgba8-bitmaps-and-back/#comments Wed, 22 Sep 2010 20:25:33 +0000 Paul Solt http://paulsolt.com/?p=641 Edited 8/24/11: Fixed a bug with alpha transparency not being preserved. Thanks for the tip Scott! Updated the gist and github project to test transparent images.

Edited 12/13/10: Updated the code on github/gist to fix static analyzer warnings. Changed a function name to conform to the Apple standard.

When I [...]]]> Edited 8/24/11: Fixed a bug with alpha transparency not being preserved. Thanks for the tip Scott! Updated the gist and github project to test transparent images.

Edited 12/13/10: Updated the code on github/gist to fix static analyzer warnings. Changed a function name to conform to the Apple standard.

When I started working with iPhone I was working with Objective-C and C++. I created a library in C++ and needed access to a bitmap array so that I could perform image processing. In order to do so I had to create some helper functions to convert between UIImage objects and the RGBA8 bitmap arrays.

Here are the updated routines that should work on iPhone 4.1 and iPad 3.2. The iPhone 4 has a high resolution screen requires setting a scaling factor for high resolution images. I’ve added support to set the scaling factor based on the devices mainScreen scaling factor

UPDATE: 9/23/10
My code to work with the Retina display was incorrect, it ran fine on iPad with 3.2, but it didn’t do anything “high-res” on iPhone 4. I was using the following:

__IPHONE_OS_VERSION_MAX_ALLOWED >= 30200

but it isn’t safe, when I run it for a universal App 4.1/3.2 it will always return 40100, and the expression didn’t make sense. (Side Note) I took this check from Apple’s website when iPad 3.2 was actually ahead of iPhone 3.1.X, but that doesn’t help with iPhone 4.1 being ahead of iPad 3.2.

The issue with iPad is that the imageWithCGImage:scale:orientation: selector doesn’t exist on iOS 3.2, most likely it will on iOS 4.2, so the following code should be safe. Some methods in iOS 4.1 don’t exist in iOS 3.2, so you need to check to see if a newer method exists before trying to execute it. There are two methods you can use depending on the class/instance (+/-) modifier on the function definition.

+ (BOOL)respondsToSelector:(SEL)aSelector   // (+) Class method check
+ (BOOL)instancesRespondToSelector:(SEL)aSelector   // (-) Instance method check

imageWithCGImage:scale:orientation is a class method, so we need to use respondsToSelector: The correct code to scale the CGImage is below:

if([UIImage respondsToSelector:@selector(imageWithCGImage:scale:orientation:)]) {
	float scale = [[UIScreen mainScreen] scale];
	image = [UIImage imageWithCGImage:imageRef scale:scale orientation:UIImageOrientationUp];
} else {
	image = [UIImage imageWithCGImage:imageRef];
}

It might help if there was some images to explain what’s happening if you don’t use this imageWithCGImage:scale:orientation: on the iPhone 4 with the correct scale factor. It should be 2.0 on Retina displays (iPhone 4 or the new iPod Touch) and 1.0 on the 3G, 3GS, and iPad. float scale = [[UIScreen mainScreen] scale]; will provide the correct scale factor for the device. The first image has jaggies in it, while the second does not. The third image, an iPhone 3G/3GS, also does not have jaggies.

iPhone 4 with default scale of 1.0 causes the image to be enlarged and with jaggies.

iPhone 4 with scaling of 2.0 makes the image half the size and removes the jaggies

iPhone 3G/3GS with scaling set to 1.0

I hope it helps other people with image processing on the iPhone/iPad. It’s based on some previous tutorials using OpenGL, which I fixed (memory leaks) and modified to work with unsigned char arrays (bitmap).

Grab the two files here or the sample Universal iOS App project:

• ImageHelper.h
• ImageHelper.m
• Xcode Project on Github

Example Usage:

NSString *path = (NSString*)[[NSBundle mainBundle] pathForResource:@"Icon4" ofType:@"png"];
UIImage *image = [UIImage imageWithContentsOfFile:path];
int width = image.size.width;
int height = image.size.height;
 
    // Create a bitmap
unsigned char *bitmap = [ImageHelper convertUIImageToBitmapRGBA8:image];
 
    // Create a UIImage using the bitmap
UIImage *imageCopy = [ImageHelper convertBitmapRGBA8ToUIImage:bitmap withWidth:width withHeight:height];
 
    // Display the image copy on the GUI
UIImageView *imageView = [[UIImageView alloc] initWithImage:imageCopy];
 
    // Cleanup
free(bitmap);

Below is the full source code for converting between bitmap and UIImage:

ImageHelper.h

ImageHelper.m

The iPad is set to revolutionize how we interact with multimedia content and computers. There are a number of reasons that make the hardware and software standout. First and foremost, it [...]]]> A lot of people have been talking about the iPad. Here are my opinions on the future of iPad, computing, and entertainment.

The iPad is set to revolutionize how we interact with multimedia content and computers. There are a number of reasons that make the hardware and software standout. First and foremost, it is affordable cutting-edge technology. The $499 price point means that it is not out of reach for average consumers who are interested in an updated “all-in-one” computing device. All 9.7 inches of the screen are multi-touch, which will allow software developers to create very interactive applications. Star Trek, Avatar, and other science fiction movie computer interfaces can finally be realized on a large multi-touch screen. The device is connected, which allows the consumer to use it anywhere. Lastly, the device will provide the ultimate responsive user experience.

Home Entertainment Revolution

Apple now has the ability to revolutionize the home entertainment market. They are provided a multi-media portal, which will change the way we use our TV’s, computers, and music players. Imagine controlling a TV from the couch without attaching any wires. A user might want to watch “Batman Begins” on their 42” HDTV. A few touches will open iTunes and start the movie. I mentioned the TV, how does that fit into the picture? The movie streams wirelessly in HD from the couch to the 42” TV. Gone are all the cables, remotes, and hassles. Don’t bother with power cable, since the device will play content for 10 hours straight. The entertainment cabinet can be cleaned out. Throw out the VCR, CD player, DVD player, Blue-Ray player, cable TV, satellite TV, and digital antennas because they are not needed. Apple will be the one stop remote control into all media content and it will be seamless to use and control.

Affordable Technology

A few years back, in 2007, Amazon set out to take over the digital books arena. They did a pretty good job at providing access to books, but that is about all they did. The Kindle DX costs $489 and is just a digital book reader. It has limited processing power and storage space. The main attraction is the e-ink technology that is supposed to be easier to read. Overall, the device is nice, but is very limited in the target audience and lacks multi-media capabilities like an iPhone.
Apple worked hard to set the price point of the iPad as close as possible to the Kindle, because they are directly competing with Kindle’s e-book market. For $10 more one can get a fully color display that can play videos, music, games, display e-books, and run applications. Apple did a wonderful job in selecting a set of features that could be combined for a relatively low price point. The device is slightly more expensive than other eBook readers and net books, but not overly expensive.

Large Multi-Touch Screen

For the longest time computers were something that required skill to use. However, this learning steep learning curve is almost no longer the case with the iPhone, iPod Touch, and iPad. The iPhone revolution brought capacitive multi-touch screens to the public. In English this means that a user just touches, not “presses,” the screen to perform actions. iPad is riding on that revolution wake and it is taking it step further by increasing the size of the screen. This technology is not foreign; it is mainstream and it is here to stay because it works. If a user knows how to use an iPhone or a laptop track pad then the transition is smooth. The touch screen is key, because it allows people to interact with a device just like they might interact with a microwave or a washing machine. A user physically touches, taps, and slides controls around that directly mirror the physical world. The iPad is a natural user interface and it is what most people what, but do not know how to ask for.

Software is Key

The main attraction with any working piece of hardware is software. People want to use a piece of hardware that is customizable. At any given point the device can assume different roles, because it was built to be extensible. In one instant it is an email program, movie player, music player, and then an entire college library. Apple has created a platform that provides many inputs and outputs that software developers can hook into to provide new and novel user experiences. The software development kit (SDK) has given developers direct access to technology that was locked down or too expensive to use. Developers can use a digital compass, accelerometer, multi-touch screen, microphone, and motion sensors to interact with a user in astonishing ways.

Connected

The iPhone provided the all-in-one experience because it can double as a music player, movie player, email program, Internet browser, and eBook reader. It was small, but it had the ability to execute each of those tasks. It has those abilities because of the Wi-Fi and 3G data connections. These connections make it possible to see content beyond the walls of a single hard drive. It provides a much richer experience to user. The iPad takes these same tasks and now makes it better by providing a bigger experience. Users can use these connections in a larger form factor and can be more productive. For most users a simple Wi-Fi connection will be all they need from the couch in the living room. Some users might be active and on the go, so they will need a 3G wireless connection. Apple has realized this connection issues and separated both technologies to reach different consumers needs. Users can get the Wi-Fi by itself, or combine Wi-Fi and 3G if they need to always have a connection the the internet.

User Experience

Users want fast responsive devices, not sluggish devices. A lot of users complain that they cannot run multiple applications (multi-tasking) on the iPhone, but what they do not realize is what they have to give up for multiple applications. Running anything in parallel on a mobile device means that it is dividing computing resources and power among applications that are invisible in the background. These resource hogs will slow a device down and drain a battery.

Traditional multi-tasking is not what users want. Apple supports multi-tasking, but only to first party applications. In restricting access, Apple has complete control of the user experience. Third-party multi-tasking is not supported for a few reasons.

• Window’s Task Manager is a power user feature that is unnecessarily complicated. On a Windows Mobile 6.x device, task manager is a terrible experience. For example, pressing the ‘X’ on an application is not guaranteed to close the application. The button may only minimize the application, in which case it is still using computing resources and draining the battery. The ability to manage open applications is a power user feature on a mobile device and should be hidden from a typical user.
• What is the difference between running an application in the background and running an application one at a time if the transition from one application to the next is fast and seamless? Does the experience have to differ solely from a technicality? iPhone applications can save state from the last thing they were doing when they are closed. For example, if a user is composing an email about a trip on an iPad. They need weather information and decide to check the weather with the following steps.
  1. Press the home button.
  2. Touch the weather application.
  3. Press the home button.
  4. Touch the email application.
  5. Resume composing the email with the updated weather knowledge.
• Running applications in the background allows companies to directly compete with Apples multimedia business. iTunes is one of the few applications like Mail and Messages that run in the background. A user can play music through iTunes while using different applications. If a user could use Pandora for music in the background, then they would have a smaller reason to stay on the iTunes platform. I do not see Apple changing this policy, since it is not in their best interest.

Conclusion

The iPad will simplify the experience to download new movies, games, music, books, and utility applications. There is no doubt in my mind that Apple will continue to innovate on this new iPad platform to further simplify and connect the multimedia experience in every persons home. The iPad is magic and just works.