Get a list of the languages that iPhone supports

Posted by on March 13, 2011 No comments 
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSArray *languages = [defaults objectForKey:@"AppleLanguages"];
NSLog(@"%@", languages);

NSMutableArray count always returns zero

Posted by on March 6, 2011 No comments

The code is as follows, rowsToUpdate is NSMutableArray *, [sites count] is greater than 0, and there is value for row index, but [rowsToUpdate count] always returns 0:

	for (int i=0; i<[sites count]; i++) {
		NSLog(@"row index: %i, %@", i, [NSString stringWithFormat:@"%i", i]);
		[rowsToUpdate addObject:[NSString stringWithFormat:@"%i", i]];
		NSLog(@"[rowsToUpdate count] = %i", [rowsToUpdate count]);
	}

There is no obvious problem with the code, and it doesn’t make sense to return 0.

After a couple of search, I found it on stackoverflow.com that I missed the initialization for “rowsToUpdate”. The fix is as follows (a couple lines of code added):

	if (rowsToUpdate == nil) {
		rowsToUpdate = [[NSMutableArray alloc] init];
	}
	else {
		[rowsToUpdate removeAllObjects];
	}

	for (int i=0; i<[sites count]; i++) {
		NSLog(@"row index: %i, %@", i, [NSString stringWithFormat:@"%i", i]);
		[rowsToUpdate addObject:[NSString stringWithFormat:@"%i", i]];
		NSLog(@"[rowsToUpdate count] = %i", [rowsToUpdate count]);
	}

Xcode Warning: “UIKeyboardBoundsUserInfoKey” is deprecated

Posted by on March 5, 2011 No comments

Simply use “UIKeyboardFrameBeginUserInfoKey” instead:

NSValue *aValue = [info objectForKey:UIKeyboardFrameBeginUserInfoKey];

NSURL Tips

Posted by on March 3, 2011 4 comments

# Loading a string from a website
(this will block until it loads)

    NSURL *url;
    NSData *data;
    NSString *blork;
    url = [NSURL URLWithString: @"https://langui.net/"];
    data = [url resourceDataUsingCache: NO];
    blork = [[NSString alloc] initWithData: data  encoding: NSASCIIStringEncoding];

# Loading an image from a website
(this will block until it loads)

    NSURL *url;
    NSData *data;
    NSImage *blork;
    url = [NSURL URLWithString: @"https://langui.net/wp-content/uploads/2011/03/banner.png"];
    data = [url resourceDataUsingCache: NO];
    blork = [[NSImage alloc] initWithData: data];

# Open an URL in iphone safari

    NSURL *url = [NSURL URLWithString: @"https://langui.net/"];
    [[UIApplication sharedApplication] openURL: url];

More tips available here: http://borkware.com/quickies/

Converting NSString* to NSData* and Vice Versa

Posted by on March 3, 2011 No comments 
NSString* str = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
NSData* data = [str dataUsingEncoding: NSASCIIStringEncoding];

How-To: URL Encode NSString in Objective-C

Posted by on March 3, 2011 No comments 
NSString *url = [@"langui.net" stringByAddingPercentEscapesUsingEncoding: NSASCIIStringEncoding];

Converting unsigned char array to NSString *

Posted by on March 2, 2011 No comments

The code snippet:

NSString* s = [[NSString alloc] initWithBytes:buffer length:sizeof(buffer) encoding:NSASCIIStringEncoding];

Calling C Functions from Objective-C

Posted by on March 1, 2011 2 comments

As Objective-C is a superset of C, it allows developers to mix pure c source files with Object-C source files.

But to call a C function from Objective-C, you should not import the .c file in your Objective-C .m file, that won’t work.

To call a C function from the Objective-C, you need to create a .h header file to include the C function declaration, and, of cause, include the .h file in the .c source file where the C function resides. Then import the .h file in the .m source file where you would like to call the C function, and simply call the function.