iPhone iOS 4 iPad SDK Development Tutorials, Programming Tips, News » objective-c

Beginners iPhone Action Game Tutorial: Source Code

John — Fri, 23 Jul 2010 01:16:50 +0000

A few weeks ago I posted a short video similar to this one:

I’ve been asked since then when I would come out with the tutorial. I was finally able to get around to completing the source file, and I’ve added line by line (well pretty close) comments in plain english to make it easier to follow.

The above video utilizes the exact source code from this tutorial running in the iPhone simulator.

Following the suggestions of a friend of mine who is just starting to learn this I’ve used as few methods as possible, and made extensive use of autorelease objects to make the flow easier to follow for beginners.

The tutorial features:

Loading/Placing Images
Animation
Touch Events
Text
Sound Effects
Background Music
Buttons
Resetting The Game

Coming up next week I will be posting a more comprehensive tutorial, but I am posting the source code now. If you look through this code and the comments you should be able to grasp what is going on, and I hope that the upcoming tutorial will fill in the gaps. Be sure to come back next week when the full tutorial is posted!

I recreated this from scratch using Sparrow Framework and Objective-C because in my findings it was easiest to follow for a beginner looking to create an action game.

Things could change a little as I haven’t really looked through it myself.. just quickly coded it and wrote line by line comments. If you open it up, and are wondering which files to look at to understand things go to the Game.h and Game.m files.. the app delegate files were created automatically with the Sparrow project and I didn’t comment those.

Update! I have modified the project to remove an error that occurred on some systems due to a recursive search being done in the project for already included files. Please re-download if you encountered this problem.

You can download the source with music/sound effects here:
BalloonGameTutorial

Graphics are included so the example will run but are slightly different because I am using graphics similar to those in the video in my own game.

As far as licensing goes feel free to use this in your own apps, and if you do send me a message or post a comment about it, and I’ll mention it on this site. You may not use any portion of this project in your own tutorials, books, etc. (and definitely don’t submit it to a site buying tutorials.. you know who you are!) without permission.

Please be sure to check back next week when the entire tutorial is posted which will give you a much better idea of how to extend/use this source code and utilize the Sparrow Framework.

If you have any questions as to why I did something or have any suggestions for the tutorial then please post them below — it will help to make the final tutorial better.

Also, if you could share this post that would be great too and help motivate me to make more!

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Phonegap And iWebKit Demo (Video and Source)

John — Tue, 09 Mar 2010 02:00:32 +0000

Randy McMillan sent me information on an example that he has posted this time illustrating the usage of Phonegap and iWebKit.

I have created a short video demoing the example in action:
This video was embedded using the YouTuber plugin by Roy Tanck. Adobe Flash Player is required to view the video.

No knowledge of Objective-C is necessary to create an app using these technologies, and as you can see the look and feel is just like a native application. In the demo the app is running in the simulator as a native app, not in Safari. While action games will suffer a noticeable performance lag, apps that are non-graphically intensive have pretty good performance.

You can download this example here:

The example can be downloaded here: iWebkit/Phonegap

iWebKit is a UI framework commonly used in web apps, and Phonegap is a framework used for running web applications as native iPhone/Blackberry/Android applications.

[Source: Randy McMillan]

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Custom Behavior On Return For A UITextView

John — Sat, 20 Feb 2010 07:45:28 +0000

The default behavior for a UITextField on pressing the return key is to execute the textFieldShouldReturn: method of the UITextFieldDelegate.

What if we wanted to create similar behavior with a a UITextView which does not have an equivalent method and by default just creates a new line?

Nick Dalton has come up with a snippet of code that uses the:

textView:shouldChangeTextInRange:replacementText:

method of the UITextViewDelegate to do just that.

You can check the article out here: Handling The Return Key In A UITextView

It’s a very handy bit of code to have as there are many situations where you may want to implement custom behavior when the return key is pressed in a UITextView.

Thanks Nick.

Please post any comments below, thanks.

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Getting Subclasses in Objective-C

John — Sat, 23 Jan 2010 07:17:38 +0000

One of the things that makes the Objective-C language “different” from most other object oriented programming languages is that there is no simple command that allows you to print the subclasses of a class. I noticed this early on when using the language, and had to work around this. I don’t know why Objective-C doesn’t have a simple command for doing this (to be honest I never thought about it until this moment), but recently I saw an article on exactly this, and found a few ways to print out those subclasses.

The article I saw was on Cocoa With Love, and entitled Getting Subclasses of Objective-C Class that explains Matt Gallagher’s approach to getting the subclasses. Overall this isn’t the most complex task in the world, but as he explains there are considerations to be made as to why you would choose his first approach over the obvious “hackers” approach which he also explains.

It’s a great read if you ever need subclasses, but as said in this Stackoverflow discussion on getting subclasses you may want to change things up if you are in need of this functionality.

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Incredible iPhone Game Programming Tutorials With Video

John — Sat, 02 Jan 2010 08:56:54 +0000

Just like to turn you guys on to what are the best video iPhone game programming tutorials on the web so far in case you haven’t seen them.

– Update Jan. 2nd 2010 – Tutorial 11 has been added, and I have upgrade this list to reflect that.

These tutorials are from 71 squared. They run through the steps to creating a game on the iPhone in tremendous detail, and include source code. Included are in-depth videos.

Here they are:

Now these gents are also writing a book on iPhone game programming. So absolutely if you like their tutorials I suggest you check it out. I don’t think it’s available for pre-order yet but you can read some info about it here.

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Amazing Xcode Tips Leave Developer In A State Of Shock

John — Tue, 20 Oct 2009 07:16:50 +0000

OMG… that’s Xcode?!

Xcode, the IDE provided by Apple for iPhone and Mac development is widely purported by beginning iPhone developers in online forums to be terrible. For awhile I believed the forum trolls, and I accepted that Xcode was a subpar IDE. In months of usage I didn’t think much of it only making a few preference changes enabling little more than code completion. Recently however, I came across a great set of tips that opened my eyes to the possibility that Xcode wasn’t as bad as these newbies (interestingly enough.. mainly Java developers) said.

A Great Set of Tips And Tricks

So a few days ago I came across a collection of Xcode tips. Now most of these tips I knew about, but a few of them I didn’t even after months of using Xcode. I hadn’t really explored all the shortcuts, or even clicked all those little buttons in the coding environment.

Link: 10 Xcode Tips And Tricks

Xcode Objective-C Macros Cheat Sheet

Since I didn’t know all those tips, I decided to look further, and while I was aware that macros had existed, I had never come across this excellent cheat sheet of the 34 most commonly used Objective-C Macros.

Link: Cheat Sheet Of Xcode Macros

How To Make Custom Macros In Xcode

Now, I’ve seen some developers upset, and even say they’d rather use TextMate. For those guys I found this post on creating custom TextMate like Macros in Xcode

Link: Custom TextMate-Like Macros In Xcode

Xcode All-In-One Window Mode

This was a great feature that I already knew about, but if you’re not using this and you hate Xcode, well, chances are not knowing this could be why:

Link: Enabling All-In-One Window Mode

Using all-in-one mode could change your life, and I’m not kidding.

Xcode Shortcut List In One Printable Page

Eventually I found this massively cool Xcode shortcut list, and yes, seriously.. there are that many.

Link: Xcode Shortcut List

Ultimately, Xcode is a very competitive IDE. Sure, when you first start it up it won’t compare with that IDE you’ve customized to your exact likings over the years, but before you added those plugins, and changed all those settings wasn’t your old IDE bad too? Once you’ve got it all set up, and understand all the features that have been shown the article above you’ll be shocked at how productive you can be with Xcode.

Be sure to check back, I’m still perfecting things, but I feel an ultimate Xcode setup guide coming on.

Photo Credit: Freedigitalphotos.net

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What iPhone Development Content Would You Like To See?

John — Thu, 15 Oct 2009 06:20:03 +0000

I’ve been at a bit of a loss for the last few days as to what sort of content to add to this site. There’s so many visitors coming now from the different search engines, and using the sites search engine that there are so many different things that people are looking for that I just don’t know what to talk about. So I’ve created this survey.

Now you can take this survey here at SurveyMonkey:
ManiacDev.Com Content Survey

It took a bit of looking to find a straight up place to create a survey on for free, but you won’t need to enter your e-mail address or anything like that. The questions are simple, they are:

1. Are there any specific iPhone development tutorials you would like to see?

Now, you can answer with any tutorials you’d like to see if you have something specific in your mind like game development, the store kit, whatever.

2. Do you feel video tutorials are helpful?

If you’ve ffollowed this site for awhile then you know that I used to create video tutorials on here (or at least try to). While most of the responses were positive I had alot of people send me messages saying my tutorials weren’t of the highest quality audio and video (well, I’m not in a studio here), I sound like I’m out of breath etc. and this discouraged me from creating videos. If you’d like to see videos again please say yes.

3. Should I continue the Soundboard creation video tutorial series?

I started, and got about 1/2 way though a soundboard creation series, but received alot of messages saying please just send the source code and forget the tutorials. If you’d like to see me continue this series please vote yes.

Anyways, thanks for reading, and if you do want to answer the survey you can find it here:
ManiacDev.Com Content Survey

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iPhone Development Floodgates Are Not Open

John — Wed, 14 Oct 2009 06:34:21 +0000

I received a question from a visitor whether I still felt it was worthwhile to learn Objective-C development with Flash supporting the iPhone, and seen alot of talk lately on iPhone programming websites talking about how there are so many different tools for creating iPhone apps that allow you to bypass the use of Objective-C in developing your own iPhone apps.

I read an article the other day called Floodgates Opened For iPhone Development. I would have to disagree, about this. As someone seen many "alternative development" solutions on other platforms, but ultimately they almost always fall completely flat some enjoy while some are able to achieve success in some specific niches such as Flash (video/2d games).

I think it’s great that Adobe is coming out with CS5 and that it will run on the iPhone, but as Louis Gerbag explains in this post the differences between the Flash apps in the app store and native apps. That being said I think there will definitely be a niche in the iPhone development market for Flash apps, I plan on taking a close look at it because at worst it should make for a very good prototyping/market testing tool.

The reason I’m not dropping Objective-C for one of these tools is simply because if you can understand Objective-C, and understand Apple’s iPhone SDK then you will be able to implement new features in your apps faster than someone who can’t, and speed of implementation is often the deciding factor in the success of any business.

So don’t worry about learning Objective-C being a waste of time, it’s really not as difficult, if you have Java/C++ experience you can check out my cheat sheet here, and start understanding some code very quickly. If you’re new to programming it is a great language to learn that will give you a solid understanding of the fundamentals.

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Get The Free Stanford iPhone Programming Course Before It Is Deleted!!!

John — Thu, 27 Aug 2009 17:43:58 +0000

Quick note for those new to iPhone programming who have not as of yet downloaded the free Stanford iPhone Programming Course.

The course construction, of this course is identical to many college courses given across North America. This course is designed for those with experience in object-oriented design, and C/C++ programming, and has been available free for some time.

If you haven’t already you can download the course through links found on the official page here:
Stanford iPhone Programming Class

This page was reset in the past, and will likely be reset very soon.

As stated above this course is designed for those who already have some programming instruction, if you are looking for a comprehensive online iPhone programming course that doesn’t have Object-Oriented design or C/C++ programming as a pre-requisite please check out this comprehensive course:
Comprehensive iPhone Programming course

Make sure that you save the Stanford iPhone programming class video and all materials in your iTunes library so that when it is removed you will still be able to access it.

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Avoid Retain Cycles In Objective-C

John — Tue, 28 Jul 2009 20:32:44 +0000

Found an excellent set of rules from Matt Gallagher on how to avoid retain cycles in Objective-C.

Uh-Oh A Class Is Still Retained Somewhere…

A problem that can occur in Objective-C is that when you start sharing objects between classes and increasing the retain count you can end up with a situation where one class inherits from another, and then when you want to release the object does not get released from memory because it is being retained by a class lower down the class hierarchy.

One Basic Rule

Now if this all sounds confusing, Matt explains everything well in his article, and has created a set of 5 rules. Ultimately it comes down to one basic rule:

"an object may only retain something indefinitely if it is hierarchically senior. If you don’t know which object is senior, you must work it out before you retain. If there is no clear senior object — you should redesign so that there is."

For a more detailed detailed explanation (with diagrams) be sure to check out: Rules To Avoid Retain Cycles

[Via: Cocoa With Love]

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