Category: CocoaCoder

Posted on

Accessing AppDelegate instance

AppDelegate object can access from any class in the same application like below. Methods or properties shared between controllers can be defined under application delegates.

SomeAppDelegate *appDelegate
  = (SomeAppDelegate *)[[UIApplication sharedApplication] delegate];
Posted on

How to access special directory on the iphone device

Use NSSearchPathForDirectoriesInDomains(). First argument “NSDocumentDirecotry” is the key to specify special directory, in this case Document directory under the application. The method returns absolute path expression.

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                               NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSLog(@"NSDocumentDirectory is %@", documentsDirectory);

Following is the list of the special directory key and result. Some keys are defined in the header file but actually they return nothing.

NSApplicationDirectory: /var/mobile/Applications/{APPID}/Applications
NSDemoApplicationDirectory: /var/mobile/Applications/{APPID}/Applications/Demos
NSDeveloperApplicationDirectory: /var/mobile/Applications/{APPID}/Developer/Applications
NSAdminApplicationDirectory: /var/mobile/Applications{APPID}/Applications/Utilities
NSLibraryDirectory: /var/mobile/Applications/{APPID}/Library
NSDeveloperDirectory: /var/mobile/Applications/{APPID}/Developer
NSUserDirectory: Not found
NSDocumentationDirectory: /var/mobile/Applications{APPID}/Library/Documentation
NSDocumentDirectory: /var/mobile/Applications{APPID}/Documents
NSCoreServiceDirectory: Not found
NSDesktopDirectory: /var/mobile/Applications/{APPID}/Desktop
NSCachesDirectory: /var/mobile/Applications/{APPID}/Library/Caches
NSApplicationSupportDirectory: /var/mobile/Applications/{APPID}/Library/Application Support
NSDownloadsDirectory: /var/mobile/Applications/{APPID}/Downloads
NSAllApplicationsDirectory: /var/mobile/Applications/{APPID}/Applications
NSAllLibrariesDirectory: /var/mobile/Applications{APPID}/Library
Posted on

Repeating background image in native iPhone app – Stack Overflow

Apparently a UIColor is not necessarily a single color, but can be a pattern as well. Confusingly, this is not supported in Interface Builder.

Instead you set the backgroundColor of the view (say, in -viewDidLoad) with the convenience method +colorWithPatternImage: and pass it a UI Image. For Instance:

- (void)viewDidLoad {
  [super viewDidLoad];
  self.view.backgroundColor =
    [UIColor colorWithPatternImage:
       [UIImage imageNamed:@"gingham.png"]];
}

Of course, don’t forget to add the image file to your application bundle.

via Repeating background image in native iPhone app – Stack Overflow.

Posted on

Applying animation while resizing or moving the view

Animation can be applied while its frame, bounds, center, transform, alpha… is being changed.  The key is set start and end values between beginAnimations and commitAnimations, so called animation block.


[UIView beginAnimations:nil context:nil];
[UIView setAnimationCurve: UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration: 1.0];

// set original position
[view setFrame:CGRectMake(0, 0, 100, 100)];

// move and grow
[view setFrame:CGRectMake(100, 100, 200, 200)];

[UIView commitAnimations];
Posted on

Create alert dialog

UIAlertView takes care of this


UIAlertView *alert = [[UIAlertView alloc]
                       initWithTitle:@"Alert View"
                       message:@"Here is an alert message"
                       delegate:nil
                       cancelButtonTitle:@"Cancel"
                       otherButtonTitles:@"OK", nil];
[alert show];

// Since alert object is allocated above, it must  be released here
[alert release];