Archive for the ‘Development’ Category

How to Take the Shine off Your App’s Icon

December 18th, 2009

Screen shot 2009-12-18 at 4.56.39 PM iPhone apps have a curved shine applied to their icons by default. It makes any icon look like it has been buffed to a high gloss. But what if you don’t want your icon to look shiny? What if you want full control over the look of your icon? Don’t fret: there are a couple of easy ways to disable the shine and take back control, and they’re both rather easy.

UIPrerenderedIcon

Screen shot 2009-12-18 at 4.45.15 PM The first method is to add a setting to your project in Xcode. Just follow these 4 simple steps to do so:

1. Open your iPhone app’s info.plist file.

2. Command-click and select Add Row.

3. Select “Icon already includes gloss and bevel effects” from the drop down that appears.

4. Check the checkbox that appears next to the new row.

Alternately, you could set this setting in your info.plist by editing it in a text editor. You just need to add the following 2 XML tags inside the <dict> tag:

<dict>
	<key>UIPrerenderedIcon</key>
	<true/>
	...

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Posted in Development

Tags: advent UIPrerenderedIcon

How to Prevent the iPhone from Sleeping

December 17th, 2009

put-the-iphone-to-sleep

Left idle, the iPhone goes into sleep mode after about a minute. This narcoleptic behaviour saves on battery life, but there are situations where you would not want the device to go to sleep. For instance, in the middle of a multiplayer game that is turn-based, such as chess. You could wait for longer than a minute for your opponent to make make their move and you wouldn’t want to miss it when they did.

To keep the iPhone awake and alert, simply run the following line of code:

[UIApplication sharedApplication].idleTimerDisabled = YES;

Do use this tip sparingly though. The iPhone’s power is unmatched, to be sure, but unfortunately it is not unlimited.

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Posted in Development

Tags: advent code objective-c UIApplication

How to Make the iPhone Vibrate

December 15th, 2009

The iPhone is capable of dazzling the user eyes by pushing impressive graphics around its screen and tickling their ears with a lot of audio to go with it, but you may want to give users of your iPhone app some additional sensory experience on top of that. You can do this by making the device vibrate.

We actually use the Audio framework to vibrate device. Here is how to do it in 3 simple steps:

1. Add the AudioToolbox framework to your target.

2. In the file you intend to trigger a vibration, import the AudioToolbox header file:

#import <AudioToolbox/AudioToolbox.h>

3. Finally, call the following line to make the device vibrate:

AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);

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Posted in Development

Tags: advent AudioToolbox code objective-c vibrate

How to Retrieve Your App Delegate Singleton Instance

December 14th, 2009

You should be familiar with the application delegate class if you have ever developed any kind of iPhone app. It is the class that contains your app’s applicationDidFinishLaunching which most if not all apps use as an entry point for execution. You might use it to keep track of application-level state variables or objects, for example.

As such, from time to time you will have a need to retrieve your app’s application delegate instance. You can retrieve it from anywhere within your app by running the following single line of code:

MyAppDelegateClass *app = [[UIApplication sharedApplication] delegate];

Just be sure to replace “MyAppDelegateClass” with your own iPhone app’s application delegate class name.

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Posted in Development

Tags: advent code delegate objective-c UIApplication

How to Get Your App’s Display Name and Version

December 13th, 2009

Have you ever needed to retrieve your iPhone app’s name or version at runtime? Sure, you can use constants in a lot of cases, but it can often save you time in the long run to make use of the information that is available via a class called NSBundle.

The Code

You can retrieve your iPhone app’s display name using the following one line of code:

NSString *appName = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayName"];

To retrieve your iPhone app’s version number, use the following similar line of code:

NSString *appVersion = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"];

Use Case

Screen shot 2009-12-13 at 12.41.07 PM In Addicus, when you click the “Get Set” button on the main menu, it links to our website and passes in the referring application name and app version as querystring parameters, allowing us to track visits to our website from different versions of all of our iPhone games. To do this, we combine the above code with code that opens a URL. Here is the resulting code:

NSString *appName = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayName"];
NSString *appVersion = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"];
NSString *url = [NSString stringWithFormat:@"http://getsetgames.com/?r=%@&v=%@",appName,appVersion];
 
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]];

Since we’re retrieving this info via the NSBundle class, we never need to change this code when we update the version of the app. The version change propagates down to the URL we open automatically. And this code can be reused in any app without changing it.

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Posted in Development

Tags: advent code NSBundle objective-c

How to Dial a Phone Number

December 12th, 2009

photo-4 With so many awesome games and apps on the iPhone, it is easy to forget that it can actually be used to make phone calls. No, really, it’s true! And as is the case with so many other pieces of functionality, this is easy to accomplish with the iPhone SDK.

Like other phones, the iPhone supports the tel application protocol in URLs. This means that all we need to use is the trusty openURL method of the UIApplication class. We have previously discussed this method when pre-composing emails and, believe it or not, opening a URL.

The Code

Here is how to dial a phone number from your iPhone app in one line of code:

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"tel:555-555-5555"]];

Dialing From a Web Page

You can also put links in your web pages that dial a phone number on the iPhone by using the tel protocol like so:

<a href="tel:555-555-5555">Dial 555-555-5555</a>

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Posted in Development

Tags: advent code objective-c UIApplication

How to Hide (and Show) the Status Bar

December 11th, 2009

On the iPhone’s 320×480 screen, pixel real estate is at a premium, especially for games. Often, the status bar represents 20 pixels of height that you as a developer just can’t afford to give away. Fortunately there are 2 simple ways to remove the status bar.

UIStatusBarHidden

uistatusbarhidden2 The first way is by adding a setting to your app’s info.plist file called UIStatusBarHidden. This is ideal for apps that should never display the status bar. Just follow these steps to change the setting:

1. Open your iPhone app’s info.plist file.

2. Command-click and select Add Row.

3. Select “Status bar is initially hidden” from the drop down that appears.

4. Check the checkbox that appears next to the new row.

You could also add this setting to your app’s info.plist file by opening it in a text editor and adding the following 2 XML tags inside the <dict> tag:

<dict>
	<key>UIStatusBarHidden</key>
	<true/>
	...

How to Do it With Code

If you need the status bar to appear and disappear at runtime, then you will need to use code to do so. You can hide the status bar with one line of code:

[[UIApplication sharedApplication] setStatusBarHidden:YES animated:NO];

And to show it again, simply call the above line and pass “NO” into setStatusBarHidden instead of “YES”. You can also fade the status bar in and out by passing “YES” into the “animated” part of the message.

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Posted in Development

Tags: advent code objective-c UIApplication UIStatusBarHidden

String Comparison Using NSString

December 10th, 2009

Photo-2a

One of the most common things a programmer needs to learn how to do when faced with a new API is how to compare one string to another to see if the two are the same or how they differ.

Because of this, many APIs have created some handy string comparison features, and the NSString class in objective-c is no exception. What follows are some invaluable tools for string comparison in objective-c.

The Is-Equal Method

The NSString class responds to a message and returns whether or not the NSString you pass in is equal or not:

NSString * str = @"oranges";
BOOL res = [str isEqualToString:@"apples"];

The Compare Method

The NSString class also has a method called compare, which gives you a bit more info in the return results. It can actually tell you the difference between the two strings; whether or not the string you passed in is:

the same,
in ascending sort order to the string you call the message on or
in descending sort order to the string you call the message on

NSString * str = @"oranges";
NSComparisonResult res = [str compare:@"apples"];
 
switch (res) {
	case NSOrderedAscending:
		// going up
		break;
	case NSOrderedSame:
		// even steven
		break;
	case NSOrderedDescending:
		// down i go
		break;
	default:
		break;
}

Insensitivity to Case

Finally, the NSString class also features a method for comparing strings without case sensitivity. This is useful for comparing strings with unpredictable case, such as user input. Like the compare method, it returns an NSComparisonResult enumerated value which allows you to see the equality or sort-order of the two strings.

NSString * str = @"APPLES";
NSComparisonResult res = [str caseInsensitiveCompare:@"apples"];
 
switch (res) {
	case NSOrderedAscending:
		// onward and upward
		break;
	case NSOrderedSame:
		// same old
		break;
	case NSOrderedDescending:
		// downfall
		break;
	default:
		break;
}

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Posted in Development

Tags: advent code NSString objective-c

How to Set Your App’s Splash Screen

December 9th, 2009

All iPhone apps have a splash screen, or what Apple refers to as a “launch image”. It is the screen that is displayed immediately after you press your app’s icon on the home screen, while the app icons are sweeping away and your app is zooming into view.

Some apps opt not to display a splash screen and go for a black screen, which is the default behaviour when you create an app. Others display a wireframe of the app’s interface in order to look like it is loading faster. See Apple’s native apps such as Clock and Camera for good examples of this. The most common use of the splash screen (especially in games) is to present a company or game logo, as we do in Addicus:

How to Do It

Apple has made it so easy to set your splash screen that you don’t even need a single line of code to do it. Why, you don’t even need to change a setting. Here’s how to set your splash screen it in just 2 steps:

1. Add a file to your project’s Resource folder called Default.png.

2. There is no step 2. Take this time to reflect on how good life is.

And that’s it. Run your app and your splash screen will zoom into glorious view.

Heads Up

A couple of things to watch out for when working with splash screens:

Whatever image you give it will be scaled to fill the 320×480 resolution of the iPhone, so ideally you would use a 320×480-sized image.

If your iPhone app is running in landscape mode, you need to rotate the splash screen you use. For example, our splash screen is rotated 90 degrees to the right in the above image.

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Posted in Development

Tags: advent Default.png launch image splash screen

How to Get the Platform Name

December 8th, 2009

With each iPhone OS-powered device that Apple has added to its lineup, along with it has come new capabilities and new APIs. Because of this, it is often necessary for an app to figure out what platform it is running on before deciding to enable device-specific functionality, such as functionality that would use the compass on the iPhone 3GS, vibration on iPhones or GPS on iPhones.

Here is a function that serves just that purpose by returning the internal name of the platform:

#include <sys/types.h>
#include <sys/sysctl.h>
 
-(NSString*)getPlatformName {
	size_t size;  
	sysctlbyname("hw.machine", NULL, &size, NULL, 0);  
	char *machine = (char*)malloc(size);  
	sysctlbyname("hw.machine", machine, &size, NULL, 0);  
	NSString *platform = [NSString stringWithCString:machine encoding:NSASCIIStringEncoding];
	free(machine);
 
	return platform;
}

Possible Values

The possible values that the above function will return when developing for the iPhone OS are listed below along with the product they represent.

Return Value	Product
i386	iPhone Simulator
x86_64	iPhone Simulator
iPhone1,1	iPhone 1G
iPhone1,2	iPhone 3G
iPhone2,1	iPhone 3GS
iPhone3,1	iPhone ?
iPod1,1	iPod Touch 1G
iPod2,1	iPod Touch 2G

Example Usage

The following is an example of an if statement that takes advantage of the results of the above function.

NSString * platform = [self getPlatformName];
 
if ([platform isEqualToString:@"i386"]) {
	// do simulator-specific stuff, perhaps enable a more verbose level of logging?
}
else if ([platform isEqualToString:@"iPod2,1"]) {		
	// do iPod-specific stuff, perhaps disable UI that refers to GPS, vibration, etc.
}
else if ([platform isEqualToString:@"iPhone2,1"]) {
	// do iPhone 3GS-specific stuff, perhaps compass related?
}