iPhone iOS 4 iPad SDK Development Tutorials, Programming Tips, News

Blocks – An Interesting Objective-C Addition In iOS 4

John — Sat, 31 Jul 2010 07:43:14 +0000

Blocks are a feature of the C language that have been added to the iPhone and iPad sdk with iOS 4.

What they allow you to do are create usable “blocks” of code that you can pass along like any object. This probably sounds a lot like a function, and they are very similar, but there is a significant difference in that they “close” around variables that are in scope before a block is declared.

I know this sounds odd, and you might be wondering when you’ll need to use them, but they certainly have their uses as there are definitely times when you will want a small block of reusable code.

You can find a complete tutorial from Mike Clark here that explains things better here:
Using Blocks In iOS 4

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[Via Joost Schuur]

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How To Push Out Notifications Locally Based On Time

John — Fri, 30 Jul 2010 06:58:29 +0000

There are times when you want to notify the user that an important event has occurred or will occur.

Push notifications are a great way to notify the user that an event has occurred and became a staple feature immediately after they were added into the iOS sdk.

Now local notifications are available that allow you to push a notification to the device that your app is running on based on time, the notifications can even be recurring.

Brandon Treb has written a great step-by-step tutorial on exactly how to do just that, which you can find here:
iPhone Programming Tutorial Notifications

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Easy iPhone Simulator Screenshots With Status Bar Removed

John — Thu, 29 Jul 2010 08:16:05 +0000

If you’ve had to take screenshots of the iPhone simulator you know what I am talking about. Things just don’t look as good if you can’t see an iPhone in the image.

The problem is that when you want the simulator in the screenshot then you need to have some sort of solid background so that you can remove it afterwards, and you will need to select out the area of the screen with the simulator and then in your imaging program remove the statusbar. This gets old fast if you are taking a lot of screenshots.

I found out about this great program that you simply load up and it will take a snapshot of the simulator statusbar removed, and if you want you can very quickly and easily take multiple screenshots.

The utility can be download here:
iPhone Simulator Cropper

Definitely a very handy tool.

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[Via: John Muchow, Alex Curylo]

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Great Beginner iPhone And iPad Dev Screencasts

John — Wed, 28 Jul 2010 07:47:48 +0000

Learning iPhone and iPad development can definitely be difficult, especially if you are not a professional software developer.

I receive e-mails every few days from people who tell me they’ve bought a book or number of books on Amazon or at the local bookstore. Unfortunately most of the “Beginner” material is meant for experienced developers who are new to the iPhone or iPad platform.

If you’re a real beginner without any program experience you might need to take a step back and look for teachings from a different perspective.

A friend of mine told me about a book that they’d been using by Dr. Rory Lewis, in his book he mentions some screencasts that he has used to help teach students at the University of Colorado. They look great for the absolute beginner and if you’ve been struggling and just want to get your foot in the door I suggest checking them out. These don’t get into very advanced material, but are very accessible and high quality. You can find the screencasts here.

The book Dr. Lewis mentioned these screencasts in (although he does mention on his website you don’t need to buy it) is available here.

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Easy iPhone and iPad Library For Communicating With Web Services – Open Source

John — Tue, 27 Jul 2010 07:45:02 +0000

Communicating with web services in your iPhone and iPad apps can be somewhat of a pain, and that’s why several open source libraries have been created to allow you to do just that.

While some of those libraries are good, I love it when someone comes up with something even easier. I found out on Twitter the other day about a great new open source library called Seriously which appears to be a very promising library for easy communication with web services and JSON parsing (XML parsing coming soon).

Just take a look at this code to grab the background image url from a twitter account:

    NSString *url = @"http://api.twitter.com/1/users/show.json?screen_name=probablycorey";

    [Seriously get:url handler:^(id body, NSHTTPURLResposne *response, NSError *error) {
        if (error) {
            NSLog(@"Got error %@", error);
        }
        else {
            NSLog(@"Look, JSON gets parsed into an dictionary");
            NSLog(@"%@", [body objectForKey:@"profile_background_image_url"]);
        }
    }];

Looks pretty good to me, short and sweet.

You can download Seriously on Github here:
http://github.com/probablycorey/seriously

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iPhone Game Physics Tutorial: Radial Gravity

John — Mon, 26 Jul 2010 20:48:48 +0000

Physics can be a great way to enhance your game.

The problem is that implementing physics in your game can be extremely challenging, but I found a couple of great examples showing how to enhance an iPhone or iPad game using radial gravity with Box2D.

The examples are from Nick Vellios, and as you can see in the example above they show how to implement radial gravity on an object so that other objects are drawn towards it (much like how planets are drawn to the sun).

The examples include:

How To Add Radial Gravity To Box 2D
Radial Gravity w/ Box2D SOURCE

And a third example on inverse radial gravity (think of objects exploding in all directions)
Bombs With Box 2D and Cocos2D

Cocos2D is used as the rendering engine in the examples.

By the way, can anyone remember the name of the nifty puzzle game that used radial gravity and won numerous indie gaming awards about 12 years ago? (yeah i’m stretching)

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Update To Action Game Tutorial Source

John — Mon, 26 Jul 2010 16:01:52 +0000

I found out about a problem with a recursive directory search being included for already included header files in the beginners action game tutorial source code which was causing an error when built on some systems.

The source has now been fixed and can be found here.

Sorry for any problems.

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The Best Resources In iOS Development July 26th 2010 (For Week 07/17-07/23)

John — Mon, 26 Jul 2010 06:59:32 +0000

Thanks again for visiting the site, once again I’ve added more resources to the site, and have quite a bit more to add this week. Things slowed down a bit form the torrid pace of great resources being released, but still there were some excellent resources.

I came out with the source code for a simple action game, and that proved to be the most popular post of the week. The complete tutorial will be coming out this week and I hope that it will put many of you on the path for those interested to create their own iPhone or iPad game. I am completing my own game which will be my first game submission to the app store for which the gameplay is similar to the tutorial.

Here’s the posts from the week 7-17 to 7-23 listed in order of popularity and tweets, enjoy!

Beginners iPhone Action Game Tutorial: Source Code – Source code for a simple action game with line by line commenting. Designed for beginners to easily follow through the flow of the code.

Find iOS Custom URL Schemes From Thousands Of Apps And Add Yours – A great site for finding the url schemes of many apps and adding your own.

How To Use The Facebook Graph API In Your iPhone and iPad Apps – A couple of outstanding tutorials on integrating with the Facebook graph api within your apps.

Free Collection Of Outstanding UIToolbar Icons – An open source collection of icons that you ccan use within your UIToolbars.

How To Implement A Socket Server For Easy App Tweaking – A great tutorial on how to set up a socket server within your apps that will allow you to tweak variables in real time.

Beginners Tutorial: Basic Touch And Animation – A tutorial illustraining how to do basic UIView animations and integrate touch events.

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How To Use The Facebook Graph API In Your iPhone and iPad Apps

John — Sat, 24 Jul 2010 08:33:51 +0000

We all know Facebook is a massive database providing a wide variety of information about hundreds of millions of people, and the Facebook app has been tremendously popular on the app store.

Accessing the “Facebook Social Graph” can be done through the Facebook graph API, Facebook Connect was provided to give developers the ability to connect their apps with the Facebook database, but pales in comparison to the Facebook Graph API.

Ray Wenderlich has written a couple of excellent tutorials utilizing the Facebook Graph API, this is an ongoing tutorial series which features:

How to authenticate the Facebook user using Oath
Getting profile information
Uploading Photos
Posting to the user’s wall
And more..

The tutorials (so far) can be found here:

How To Use Facebook’s New Graph API from your iPhone App – featuring how to connect to the Facebook graph API, and authenticate the user.

How To Get a User Profile with Facebook’s New Graph API from your iPhone App – How to gather profile data from the Facebook graph api using ASIHttpRequest, and parse the data using the JSON framework.

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Find iOS Custom URL Schemes From Thousands Of Apps And Add Yours

John — Fri, 23 Jul 2010 19:28:25 +0000

I received an e-mail asking about how to find custom URL schemes for specific applications.

Just in case you are unfamiliar with a custom url scheme – this refers to binding your app to a specific url scheme such as twitter:// which when used will execute the related app on the user’s iOS device. What’s really cool is that you can attach custom parameters depending on the app for example:
twitter://post?message=visit%20maniacdev.com

You simply load the url, and the app opens.. it’s that easy.

There are literally hundreds and I was reminded about a site just the other day by Alex Curylo that has grown leaps and bounds since I last looked at it, and it lists many of these URL schemes.

That site is handleOpenUrl.com and you can search for specific applications or even for specific types of applications, for example here’s what comes up when I search for Twitter apps:
?

What’s really cool is that if you click on one of the selections it gives examples on how to use a specific app’s url scheme like this:

If you would like to know how to add a URL scheme into your own app iPhone developer tips has this great tutorial:
Launching Your Own App Via A Custom Url Scheme

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[Via: Alex Curylo]

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