This is a repost of my original article which I posted on my own website. But since it is related to iOS development, I thought it might be interesting for the Cocoaheads Belgium folks as well.

Colors Everywhere

Well, after my previous post I continued doing some more work on my UI and trying to create my own Style for UITableViews and UITableViewCells. I ended up using the same colors over and over again in all different places in my application. In the end I had code in my UITTableViewController which set the Color for the Background and the navigation bar :

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Uncomment the following line to display an Edit button in the navigation bar
    // for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem;
    [[self navigationController] navigationBar].tintColor = [UIColor brownColor];
    UIImage *img = [UIImage imageNamed:@"BG_Pink"];
    [[self tableView] setBackgroundColor:[UIColor colorWithPatternImage:img]];
}

This was all working out quite nicely …

Using the same color scheme in other Views

Data Entry View with ColorScheme

Of course, my application consits of a few different UITableViews and I even added a data entry View and a detail view. As you can see, the data entry view is using the same background color for the UITableView and the UITableViewCells are using the same color as my other UITableView as well.

At some point, I wanted to change the color scheme I was using (it was more pinkish at the start), and use something more Orange or brown like. Sadly this required me to change the color in every spot where I was using it. When I tested it on my phone, it looked horrible, since I forgot to change a few colors.

Since I’m still developing some basic ideas for the app, and the color scheme might change a few times during the Development cycle, I started thinking. There surely must be an easier way to handle this, which wouldn’t require me to change the colors in 10 different places.

Of course, I could subclass UIColor and add my own colors to it, but I wanted to try a different approach

The Categories Approach

During the iOS bootcamp I took at Big Nerd Ranch Europe a while back, we touched on the subject of Categories. Categories allow you to extend a class without the need to Subclass it. Using Categories I could quickly add a few methods to UIColor whithout the need to create a new Subclass.

Creating a Category in UIColor

Creating a new category is actually quite easy. In my case, I wanted a category on UIColor so I could extend it. I created a new Header and Implementation file and called it UIColor+MyApp.h and UIColor+MyApp.c

The Header File

In the Header file UIColor+MyApp.h I added the following code :

//
//  UIColor+MyApp.h
//
//  Created by Stefaan Lesage on 11/11/10.
//  Copyright 2010 Devia. All rights reserved.
//

#import 

@interface UIColor (MyApp) 

+ (UIColor *)myTableViewBackgroundColor;
+ (UIColor *)myTableCellBackgroundColor;

@end

This simply declares a category MyApp on UIColor, and defines 2 new methods on it. myTableViewBackgroundColor which will return the Default color which should be used as the background for my UITableViews, and myTableCellBackgroundColor which defines the default color which should be used as the background for my UITableViewCells (and in some other places in my app).

The Implementation

In the Implementation file UIColor+MyApp.m I added the following code :

//
//  UIColor+MyApp.m
//  Phocation
//
//  Created by Stefaan Lesage on 11/11/10.
//  Copyright 2010 Devia. All rights reserved.
//

#import "UIColor+MyApp.h"

@implementation UIColor (MyApp)

+ (UIColor *)myTableViewBackgroundColor
{
    UIImage *img = [UIImage imageNamed:@"BG_Pink"];
    return [UIColor colorWithPatternImage:img];
}

+ (UIColor *)myTableCellBackgroundColor
{
    return [UIColor colorWithRed:255/255.0 green:240/255.0 blue:255/255.0 alpha:100];
}

@end

Well the implementation is pretty straightforward. For the myTableViewBackgroundColor, I simply return a UIColor based on the pattern in my previous post. The myTableCellBackgroundColor then returns the light pink / purple color which gets used as the background for my UITableViewCells.

Using the Category

Using the Category is now pretty Straight Forward. In my Detail View for example, I have a reference to a UITextField called nameTextField and to the tableView beneath it. So in my viewDidLoad I have the following code :

- (void)viewDidLoad
{
    [super viewDidLoad];

    /* Load our HeaderView if Necessary */
    [[self view] setBackgroundColor:[UIColor myTableViewBackgroundColor]];
    [[self tableView] setBackgroundColor:[UIColor myTableViewBackgroundColor]];
    [nameTextField setBackgroundColor:[UIColor myTableCellBackgroundColor]];
}

Quite simple, isn’t it ?

But what are the advantages ?

For me, it makes my code a little more readable (that is of course a more personal opinion), but what’s even better is that my code is a lot easier to maintain. If for some reason I want to change my color scheme to use another pattern or another color for the UITableViewCells, I only need to update the code in one sport. Simply modify the Implementation found in UIColor+MyApp.c, build and it’s done !

Once I found the advantages of this approach, I even added more methods to my UIColor+MyApp category. It now also contains methods which return the color I will be using for the UINavigationBar tine, colors I will be using for different texts in my application, …

Feedback

As with my previous post, there might be better ways to achieve the same thing. If you have a more appropriate approach or solution, feel free to let me know … I’m eager to learn

This is a repost of my original article which I posted on my own website. But since it is related to iOS development, I thought it might be interesting for the Cocoaheads Belgium folks as well.

The default grouped UITableView

The default Grouped UITableView looks nice but …

Well, you can use the UITableView in it’s Plain mode, but also in a Grouped mode. The Grouped mode uses some kind of pattern as the background for the UITableView. It looks quite nice and is made up of alternating light and darker blue-grayish lines.

I wanted someting a little more ‘Special’ …

Although the default look isn’t all that bad … I wanted to have something ‘special’ for my application. So I was wondering if there was some way to change the color used in that pattern. Since I didn’t know the answer myself, I sent out a tweet. I was hoping someone would pick it up and maybe let me know where I could find some more information on this topic.

The feedback I got

I did receive some feedback to my tweet: ‘Is there an easy way to create your own UIColor which looks like the ‘Group Table View Color’ but with another color scheme ? #iphonedev. One of the answers was from Amar Kulo who suggested to supply me with some Photoshop files I could modify.

A few moments later, Amar Kulo even provided me with a complete answer and wrote a blog post about it to help me out. It is actually pretty easy, so I thought i would share it with the world as well.

The Trick

It is actually quite easy to get your own custom background. You simply have to use a custom background image. Amar provides a few samples in his blogpost. The only thing you need to do is open up your favorite Image Editor (in my case Pixelmator), change the colors to you liking and create the necessary versions for your application.

The Code

Once you added the resources to your project, you can simply start using them as the background for your Grouped UITableView. In my case, it was simple a matter of setting the background color in the ViewDidLoad of my UITableViewController :

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Uncomment the following line to display an Edit button in the navigation
    // bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem;
	UIImage *img = [UIImage imageNamed:@"BG_Pink"];
	[[self tableView] setBackgroundColor:[UIColor colorWithPatternImage:img]];
}

Feedback

I ended up with this Bakcground and Color Scheme

Well … This might not be the best way to do it, so if you have any suggestions, feel free to let me know.

Personally, I had to experiment a bit with quite a few different colors before I got something which did looked OK to me, so feel free to experiment as well, and let me know what you come up with

Next time I’ll be delving a little deeper into some more things I did with my UITableView and UITableViewCell … but for now … feel free to post a comment and have a look at the result :

Well, last month Eric Bariaux gave a presentation on Automated Testing in an iOS World during our Cocoaheads Belgium Meeting. I did video tape the session, but didn’t really find the time to process it yet … until then end of last week.

So I finally Imported the HDV Tapes, did some color correction, added a few titles, exported the whole thing … and ended up with a 90 GB file. I had to compress this into a smaller format for uploading and ended up with an 700 something Mb file which I uploaded to Vimeo.

Automated testing in an iOS World – Cocoaheads Belgium from Stefaan Lesage on Vimeo.

Audio Quality

I know the audio quality isn’t superb … We did have a lot of noise from the activity in the room next to ours, and I couldn’t really filter that out without messing up the rest of the audio. Next time I’ll try to bring an Audio Interface and a Microphone so we can record the audio separately.

High Quality Version

The file I uploaded had a resolution of about 640 x 360 pixels, which is perfect for displaying on an older iPhone / iPod Touch, but somehow low quality for viewing on the iPad. If people are interested in a higher quality version, I could generate an iPad specific version for you, but I won’t be able to upload that to Vimeo due to the file size.

Next Meeting

Well, since we should have had this months meeting yesterday … we will be skipping it and try to organize the next one on the 20 th December (if that’s find with everyone). We are still looking for a location or a topic, but we could also make it a ‘coding’ session if we can’t find someone to give a presentation.

Final Note

If anyone thinks he can help us out with one of the ideas mentioned in this topic, please do contact us. If you still have more ideas … well contact us as well., or even better … start organizing

Regards,

Stefaan

The very first book I read on Cocoa Programming was Cocoa(R) Programming for Mac(R) OS X (3rd Edition), and I wrote a review about that a while ago. Meanwhile I’ve been reading quite a few books on iPhone Programmings, and I even had the chance to met up with Aaron Hillegass at the NSConference. Meanwhile the folks at the Big Nerd Ranch released the iPhone Programming this new book which focuses on iPhone development. Since I learned a lot from the very first book, I decided to buy the iPhone Programming: The Big Nerd Ranch Guide (Big Nerd Ranch Guides)
and read through it.

The book itself

Since reading my first Cocoa related book, I did learn a few things and started to learn some iPhone development. Most of the things I know is from stuff I read in books, on websites and by experimenting myself. The iPhone Programming: The Big Nerd Ranch Guide (Big Nerd Ranch Guides) book itself is organized in a format which helps you learn the concepts and how things fit together. The book really helps you gather new knowledge and provides you with some techniques and sample source code which you can reuse in your own projects.

What I particularly loved in the book is that it follows some type of classroom format. For example, early in the book you will learn things about Delegation, Core Location, Views and start with a small project. Later on in the book, you will learn about the UINavigationController and use the same project to add the new things to it. This approach worked a lot better for me. Most other books teach you something with a small example, but this book uses a few sample applications throughout the whole book. The further you get in the book, the bigger the application gets and the more things you will use in it. I really LOVED that approach !

Conclusion

I have to say, I’ve been reading quite a few iPhone development related books. Most of them teach you a specific topic in a Chapter and then another topic in the next Chapter. The power of the iPhone Programming: The Big Nerd Ranch Guide (Big Nerd Ranch Guides) is that it actually takes what you’ve learned in the first chapters of the book onto the next ones, allowing you to build on what you’ve learned so far.

The examples in the book are really worth it. Once you worked yourself through the book, you won’t have a set of 25 applications each showing one thing covered in the book. Instead you’ll have a set of 10 applications which combine everything you’ve learned and have enough sample code to get you going.

Additionally, the book contains quite a few challenges. Most of the time, there is more than one way to solve the challenges, so you won’t find any solutions in the book. This made me really think about the problem at hand, and not look to the solutions to see if I understand them. In case you have a problem with one of the challenges, or anything else in the book, the folks at the Big Nerd Ranch have set up a forum in which you can ask questions.

One thing to note though, is that the book was published before iOS 4 was released, so it doesn’t contain anything specific to iOS 4. Similarly the book does contain a chapter on Preparing for the iPad, but that chapter is limited. I really hope they will make a new book which focuses more on iOS 4 and iPad development as well. The forum has a few solutions to problems with iOS4 breaking some of the examples in the book, so go ahead and check those out as well.

All in all, a fantastic book for beginners and those of you who already did some iPhone programming as well.

Amazon Links

Just so you guys know … The links to the Amazon books in this article are Affiliate Links, meaning if you would buy the book by clicking on this link, a small percentage of the purchase prices will flow back to the Belgian Cocoaheads community.

This month the meeting will take place in Gent on the 23rd of August.  Steven Vandeweghe (Blue Crowbar Software) will be showing us how he uses Git as a Version Control System during his daily life as a developer.  We might also get some additional info on SVN by Eric Bariaux (TinSys) and Mercurial by Raphael Sebbe (Creaceed). As you can see, this promises to bring out some interesting discussions on Version Control Systems.

The location for this month’s meeting is in the offices of SHPArtners – Roving Bird, Kortrijksesteenweg 1099a, 9051 Gent.

The meeting will start at 20:00, and there will be plenty of time to meet up with other Cocoa Heads BE enthousiasts. So if you’re interested, feel free to go to the EventBrite website and sign up, since spaces are limited.

You can find more information on CocoaHeads Belgium a the CocoaHeads Belgium website, in the CocoaHeads Google Groups and I even created a Linked In group for CocoaHeads Belgium.

Registration for this Meeting can be done on the Eventbrite page. If you have suggestions for future sessions or are willing to give a session, that would be the perfect time to let us know.

Well, I would like to thank Tom Maes and the kind folks at Sun Microsystems Belgium once more for allowing us to use the room for our Cocoaheads Belgium meeting.

It took us a while again to get everyone subscribed for this event, and to find an appropriate location, and sadly this time we had to limit the number of seats available. I hope everyone got in though, and if you didn’t make sure you register for the next meeting ASAP (or at least when we have more info about it). This time we had a room filled with about 30 people, at least a dozen of iPads, and even two iPhone 4 devices !

This month Tom Maes prepared a session on all things WWDC. Tom gave us his opinion about WWDC and why he finds it so interesting. As with many conferences, the sessions are quite interesting, but at WWDC you also have the opportunity to have some Lab Time with Apple Technicians which proves to be very valuable. He also mentioned that the conference isn’t always held in the session rooms, but quite a few times you meet up with interesting people in the lobby or hallways and you probably learn a few things there too.

Status Update

Personally I am very pleased with the way the Cocoaheads Belgium community is growing and evolving. I remember the first meeting where we all seemed strangers … but meanwhile we’ve grown acquainted to each-other and the sharing of knowledge and information is starting to be a fact !

I’ve had quite a few suggestions and ideas from the community last month and we have discussed a few of those during the meeting as well. For those of you who didn’t make it to the meeting, I’ll give you a little summary on the 2 most important suggestions.

NSCoder Nights

The goal here is to get together with a small group of developers and actually Code together. The idea exists in other countries and there is even a website dedicated to NSCoder Nights.

The actual goal is to have a weekly / bi-weekly event where a small group of Cocoa developers get together and … well code of course ! The big difference between the NSCoder Night and regular meetings is that the idea is to work in smaller groups, and be less formal. There would be no need to subscribe at all, if you feel you’re ready for an NSCoder Night you just turn up with your Mac and a project you want to work on.

It would be a great opportunity to share our knowledge ! One person could have an issue with some Core Location stuff and another developer could help him with the task at hand. I have already seen that we have quite a few smart people in our community, some know everything about Core Location, others about Core Animation and even some OpenGL experts. We are probably all experts in a specific area, but imagine what we could do if we could bring all that knowledge together … wel that’s exactly the idea of the NSCoder Night!

We have no concrete plans yet, but I noticed that the people present at the meeting would be interested in it, so here is a little list of things we would probably need :

• Spot with enough electricity / chairs to host a small group of developers
• Preferably a calm, not too noisy location
• If possible some Wifi access to the interent
• Some drinks / food in the neighboorhood would be great as well

In many cases it is done in a Pub with Wifi, which makes it absolutely perfect if it isn’t all too noisy (we still need to hear the each-other think & talk).

So, if anyone has a suggestion of a place where we could host the NSCoder Nights, please let us know. Remember this is supposed to be a smaller group, and there is no problem at all with having it take place in 2 or more places in Belgium at the same time. For example, I could imagine one in Antwerp, one in Gent, one in Brussels, …

NSBBQ

The other idea is a suggestion for a more social happening. From time to time we get together for our meetings, and we even take some time to grab a beer together and that’s how the idea started to grow. And if there is one thing we Belgians love on hot sunny days, … its a BBQ with good food and a few drinks! (if you answered : creating iPhone apps in 1 day, you should check the NSCoder Night topic again)

The idea is to plan a day where the whole community could meet up and socialize. Since there is no technical content attached to this event, you could even bring your girl/boyfriend, husband/wife and maybe even the kids.

We have absolutely no idea yet on how we should organize this. For now it’s a wild idea, but a quite interesting one. With the help of the community we could get it organized (find a location, catering, …) or we might even be able to do it ourselves (bring our own food, do the BBQ ourselves).

If you are interested in this idea, and have some suggestions / can offer a helping hand, please get in touch with us.

Feedback & Suggestions

If you have any feedback on the topics mentioned or have any other suggestions at all, feel free to get in touch with us. You can reach us through our Google Group for CocoaHeadsBE and CocoaHeadsBE group on LinkedIn, and of course our CocoaHeads Belgium webiste / Blog. Furthermore you can also follow the CocoaheadsBE twitter account to learn more about us.

Next Meeting

As of yet, the date is undecided. If we keep our schedule, the next meeting would be on the 26th of July, but that will probably be during most people’s summer holidays. Personally I’m out of the country during the last 2 weeks of July, but that doesn’t mean you guys can’t have a meeting without me.

Some people suggested we should skip July and jump straight forward to August. Who knows, we might be able to organize our NSBBQ during the summer holidays for those of you eager to see me before the end of august

Final Note

If anyone thinks he can help us out with one of the ideas mentioned in this topic, please do contact us. If you still have more ideas … well contact us as well. There is a real need for a CocoaHeads Belgium, and I’m sure that we can make it happen if we all work on it together.

Regards,

Stefaan

This month the meeting will take place in Brussels on the 28th of June. Tom Maes and the folks at Sun Microsystems Belgium have been kind enough to provide us with a location in which we can hold this month’s meeting.

The address for this month’s meeting is Sun Microsystems Belgium, Lozenberg 15, 1932 Zaventem.

Tom will be presenting a session on “WWDC 2010 – The non-NDA parts”.

The meeting will start at 20:00, and there will be plenty of time to meet up with other Cocoa Heads BE enthousiasts. So if you’re interested, feel free to go to the EventBrite website and sign up, since spaces are limited.

You can find more information on CocoaHeads Belgium a the CocoaHeads Belgium website, in the CocoaHeads Google Groups and I even created a Linked In group for CocoaHeads Belgium.

Registration for this Meeting can be done on the Eventbrite page. If you have suggestions for future sessions or are willing to give a session, that would be the perfect time to let us know.

Well, I would like to thank Raphael Sebbe and Sandrine Louiseau from Creaceed once more for allowing us to use the room for our Cocoaheads Belgium meeting.

The room was filled once again, and I think we had approximately 20 people joining us this time (and about 8 iPads I believe). Of course all the familiar faces were there again, and we also had some newcomers there too.

This month Raphael Sebbe prepared a session about XCode for us. Raphael is a developer from Creaceed who are the creators of some Mac and iPhone products like Prizmo, Hydra and Vocalia. And Raphael showed us how he is using XCode for a few things, learned us some new keyboard shortcuts and showed us a few Tips and Tricks. All in all, it was a great session both for beginners like me and more advanced XCode users.

Cocoaheads Belgium – Raphael Sebbe – XCode : Basics & Beyond – April 2010 from Stefaan Lesage on Vimeo.

You can find a PDF version of the actual presentation on the Creaceed website.

Status Update

Before the session started I gave a little Status Update on things we have already done since the last meeting. As we all know by now, we have our Google Group for CocoaHeadsBE and CocoaHeadsBE group on LinkedIn, and of course our CocoaHeads Belgium webiste / Blog. Furthermore you can also follow the CocoaheadsBE twitter account to learn more about us.

I would like to encourage everyone to help us fill it with content you guys are looking for. A great example here is the Book Reviews like the ones posted by Spencer Pieters. The more content we have, the more visitors the website will generate, and the easier it will be for Cocoaheads Belgium to achieve some things.

If you have a Cocoa Problem, feel free to post it in our Google Group … if you have an interesting tutorial to share you can always post it on the CocoaHeads Belgium website. Even if you post it on your own website, we would appreciate a little post on the CocoaHeads Belgium website which links through to your website for the full content.

Next Meeting

We decided that the next meeting will be on monday, the 31st of May. Currently we are still looking for a room we could use to hold the meeting, and also for someone to hold an actual session on something.

So, if you do know of a location we could use, or are willing to present something related to Mac / iPhone or iPad development, please get in touch with us.

Final Note

If anyone thinks he can help us out with one of the ideas mentioned in this topic, please do contact us. If you still have more ideas … well contact us as well. There is a real need for a CocoaHeads Belgium, and I’m sure that we can make it happen if we all work on it together.

Regards,

Stefaan

This month the meeting will take place in Mons on the 26th of April. Raphael and Sandrine from Creaceed have been kind enough to provide us with a location in which we can hold this month’s meeting. The location for this month’s meeting is La Maison de l’Entreprise (LME), Parc Scientifique Initialis, 2 Rue Descartes, 7000 Mons. Raphael will be presenting a session on “XCode, Basics and Beyond”, which should be quite interesting for even the novice and more advanced developers in the community.

The meeting will start at 20:00, and there will be plenty of time to meet up with other Cocoa Heads BE enthousiasts. So if you’re interested, feel free to go to the EventBrite website and sign up, since spaces are limited.

You can find more information on CocoaHeads Belgium a the CocoaHeads Belgium website, in the CocoaHeads Google Groups and I even created a Linked In group for CocoaHeads Belgium.

Registration for this Meeting can be done on the Eventbrite page. If you have suggestions for future sessions or are willing to give a session, that would be the perfect time to let us know.

I’m a big fan of Apress books as I find they offer very good value for money. I visit the Apress site on regular basis to check out upcoming titles on iPhone and Mac development. There was one book that was announced quite some months ago, but the release date kept slipping and slipping.

That book is the one I’d like to review today and it’s called “Learn Cocoa on the Mac”.

First of all, I’d like to point out that this book does *not* cover iPhone development. This is about Cocoa and Mac applications. Of course, with Cocoa Touch being a subset of Cocoa, you will recognize design patterns that you use on the iPhone and of course topics like Core Data can be used in both Cocoa and Cocoa Touch.

The chapters in this book are:

1. Must love Cocoa
2. Hello, World
3. Lights, Camera… Actions!
4. GUI Components
5. Using Table Views
6. Cocoa Bindings
7. Core Data Basics
8. Core Data Relationships
9. Search and Retrieve Core Data with Criteria
10. Windows and Menus and Sheets
11. Document-Based applications
12. Exceptions, signals, errors and debugging
13. Drawing in Cocoa
14. Advanced Drawing Topics
15. Working with files
16. Concurrency
17. Future paths

I’m not going to go through all the chapters in detail as the titles are clear enough.

You can see that the base of subjects is *very* wide and that is what makes this book a really great one. I find the explanations of the subjects and the samples really great. I felt really comfortable and got more confident going through this book, occasionally going through chapters very fast because of my knowledge of Cocoa Touch.

The nature of this book is really great. We all know that there are dedicated books on subjects such as Core Data and graphics. However, “Learn Cocoa on the Mac” does a great job of giving great introductions and clear explanations of what is going on. It goes deep enough into its subjects to make you understand what’s going on.

I love this book. I had great expectations of it and it didn’t disappoint. This goes easily in my personal top 3 of Cocoa books.

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