Shabbir's Code Snippets

Objective-C code snippets that you might find useful for your own projects

[shabzcode-blog]

Follow a username on Twitter iOS 5+

This easy snippet allows you to specify a username you'd like your users to follow. For instance, in an About page you can add a "Follow Me" button that checks the users logged in twitter accounts and follows you with the first available account.

Simply use:

[self follow:@"shabzcohelp"];

-(void) follow:(NSString *) username { if ([TWTweetComposeViewController canSendTweet]) { // Create account store, followed by a twitter account identifier ACAccountStore *accountStore = [[ACAccountStore alloc] init]; ACAccountType *type = [accountStore accountTypeWithAccountTypeIdentifier:ACAccountTypeIdentifierTwitter]; [accountStore requestAccessToAccountsWithType:type withCompletionHandler:^(BOOL granted, NSError *error) { if(granted) { NSArray *accountsArray = [accountStore accountsWithAccountType:type]; // Sanity check if ([accountsArray count] > 0) { //Create dictionary to pass to followWithAccountInfo: method NSMutableDictionary *dict = [NSMutableDictionary dictionary]; [dict setObject:username forKey:@"usernameToFollow"]; //Follow the username with your first logged in account [dict setObject:[accountsArray objectAtIndex:0] forKey:@"account"]; [self performSelectorOnMainThread:@selector(followWithAccountInfo:) withObject:dict waitUntilDone:NO]; } else { //No Accounts Available } } }]; } } -(void) followWithAccountInfo:(NSDictionary *) dictionary { ACAccount *acct = [dictionary objectForKey:@"account"]; NSString *username = [dictionary objectForKey:@"usernameToFollow"]; // Build a twitter request for following the username specified TWRequest *postRequest = [[TWRequest alloc] initWithURL: [NSURL URLWithString:@"http://api.twitter.com/1.1/friendships/create.json"] parameters:[NSDictionary dictionaryWithObjectsAndKeys:username, @"screen_name", @"true", @"follow", nil] requestMethod:TWRequestMethodPOST]; // Post the request [postRequest setAccount:acct]; // Block handler to manage the response [postRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {NSLog(@"%d", urlResponse.statusCode); [postRequest release];}]; }

[shabzcode-blog]

iOS 6 SupportedOrientations with UINavigationController

You probably already know that -shouldAutorotateToInterfaceOrientation had been deprecated in iOS 6 and we were told to move to -shouldAutorotate and -supportedInterfaceOrientations, but me and apparently many others on SO and on the Apple forums were having trouble if the rootViewController in the AppDelegate was anything besides a UIViewController.

So here's my solution that could probably work if you subclassed UITabBarController also.

My subclassed UINavigationController that is Orientation Aware of it's top-most ViewController.

(I will provide the class files at the bottom of the post)

So First of all you'll override these 2 methods so that the top viewcontroller of the hierarchy will take control of the orientation.

-(NSUInteger)supportedInterfaceOrientations { return [self.topViewController supportedInterfaceOrientations]; } -(BOOL)shouldAutorotate { return YES; }

Now whichever ViewController's you don't want to rotate add these lines of code.

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return (interfaceOrientation == UIInterfaceOrientationPortrait); } -(BOOL)shouldAutorotate { return NO; } -(NSUInteger)supportedInterfaceOrientations { return UIInterfaceOrientationMaskPortrait; }

And for any ViewController that you do want to be able to rotate and code like this

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown); } -(NSUInteger)supportedInterfaceOrientations { return UIInterfaceOrientationMaskAllButUpsideDown; } -(BOOL)shouldAutorotate { return YES; }

Here are the class files for the Orientation-aware UINavigationcontroller

[shabzcode-blog]

Easy way to check if current device is iPhone 5 or new iPod Touch

if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) { CGSize result = [[UIScreen mainScreen] bounds].size; if(result.height == 480) { // iPhone Classic } if(result.height == 568) { // iPhone 5 or new iPod Touch } }

[shabzcode-blog]

Format a Phone Number

Here's a code snippet that let's you pass in a phone number and get a formatted version outputted.

For instance 1234567890 ---> [phone]

- (NSString *)formatPhoneNumber:(NSString *)phoneNumber { NSArray *usFormats = [NSArray arrayWithObjects: @"+1 (###) ###-####", @"1 (###) ###-####", @"011 $", @"###-####", @"(###) ###-####", nil]; if(usFormats == nil) return phoneNumber; NSString *output = [self strip:phoneNumber]; for(NSString *phoneFormat in usFormats) { int i = 0; NSMutableString *temp = [[[NSMutableString alloc] init] autorelease]; for(int p = 0; temp != nil && i < [output length] && p < [phoneFormat length]; p++) { char c = [phoneFormat characterAtIndex:p]; BOOL required = [self canBeInputByPhonePad:c]; char next = [output characterAtIndex:i]; switch(c) { case '$': p--; [temp appendFormat:@"%c", next]; i++; break; case '#': if(next < '0' || next > '9') { temp = nil; break; } [temp appendFormat:@"%c", next]; i++; break; default: if(required) { if(next != c) { temp = nil; break; } [temp appendFormat:@"%c", next]; i++; } else { [temp appendFormat:@"%c", c]; if(next == c) i++; } break; } } if(i == [output length]) { return temp; } } return output; } - (NSString *)strip:(NSString *)phoneNumber { NSMutableString *res = [[[NSMutableString alloc] init] autorelease]; for(int i = 0; i < [phoneNumber length]; i++) { char next = [phoneNumber characterAtIndex:i]; if([self canBeInputByPhonePad:next]) [res appendFormat:@"%c", next]; } return res; } - (BOOL)canBeInputByPhonePad:(char)c { if(c == '+' || c == '*' || c == '#') return YES; if(c >= '0' && c <= '9') return YES; return NO; }

[shabzcode-blog]

How long since a particular date?

This code snippet let's you see how long it's been since a startDate compared to the currentDate.

For instance if the startDate was Today at 5:00pm and the currentDate is Today at 7:00pm. This would return 2 hours ago. This only covers days, minutes, hours and seconds, but you can add month, year and so on.

-(NSString *) calculateTimeSince :(NSDate *)startDate { NSString *dateString = @""; NSDate *currentDate = [NSDate date]; NSDateComponents *components = [[NSCalendar currentCalendar] components:NSDayCalendarUnit| NSMinuteCalendarUnit|NSHourCalendarUnit fromDate:startDate toDate:currentDate options:0]; if ([components day] != 0) { dateString = [NSString stringWithFormat:@"%d day%@ ago", [components day], ([components day] > 1 ? @"s" : @"")]; } else if ([components hour] !=0) { dateString = [NSString stringWithFormat:@"%d hour%@ ago", [components hour], ([components hour] > 1 ? @"s" : @"")]; } else if ([components minute] !=0) { dateString = [NSString stringWithFormat:@"%d minute%@ ago", [components minute], ([components minute] > 1 ? @"s" : @"")]; } else { dateString = @"Seconds ago"; } return dateString; }

[shabzcode-blog]

URL encoding that actually works...

There are numerous ways of URL encoding, but this is only approach that worked for me in almost all cases.

- (NSString*)urlEncode:(NSString *)string { NSStringEncoding stringEncoding = NSUTF8StringEncoding; NSString *newString = NSMakeCollectable([(NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (CFStringRef)string, NULL, CFSTR(":/?#[]@!$ &'()*+,;=\"<>%{}|\\^~`"), CFStringConvertNSStringEncodingToEncoding(stringEncoding)) autorelease]); if (newString) { return newString; } return @""; }

[shabzcode-blog]

Singleton Class Template

Here is a template of the singleton class that I use for almost all my projects. 

Globals.h:

#import <Foundation/Foundation.h> #import "AppDelegate.h" @class AppDelegate; @interface Globals : NSObject + (Globals *) instance; - (BOOL) isiPad; - (BOOL) isPortrait; - (AppDelegate *) delegate; @end

Globals.m:

#import "Globals.h" @implementation Globals - (id)init { self = [super init]; if (self) { } return self; } + (Globals *)instance { static Globals *instance = nil; @synchronized(self) { if (instance == nil) { instance = [[Globals alloc] init]; } } return instance; } /*Checks if device is iPad or iPhone*/ -(BOOL) isiPad { if (UI_USER_INTERFACE_IDIOM()==UIUserInterfaceIdiomPad) { return YES; } return NO; } -(AppDelegate *) delegate { return [UIApplication sharedApplication].delegate; } -(BOOL) isPortrait { UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation; return (orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown); } - (void)dealloc { [super dealloc]; } @end

This class can be used by any file by using one line of code like so:

[Globals instance].isiPad;

You can download the template class here: Globals

[shabzcode-blog]

Parse string value between two html tags

This is a simple way of parsing out a value from in between an html tag without having to add any XML parsers.

For instance: <tag>Some Important Information</tag>

This will return: Some Important Information

-(NSString *) getValueBetweenElement:(NSString *) element inHTML:(NSString *) html { NSString *result = nil; // Determine element location NSRange elementRange = [html rangeOfString:[NSString stringWithFormat:@"<%@>", element] options:NSCaseInsensitiveSearch]; if (elementRange.location != NSNotFound) { // Determine end tag location based on beggining tag location NSRange endElementRange; endElementRange.location = elementRange.length + elementRange.location; endElementRange.length = [html length] - endElementRange.location; endElementRange = [html rangeOfString:[NSString stringWithFormat:@"</%@>", element] options:NSCaseInsensitiveSearch range:endElementRange]; if (endElementRange.location != NSNotFound) { // Tags found: retrieve string between them elementRange.location += elementRange.length; elementRange.length = endElementRange.location - elementRange.location; result = [html substringWithRange:elementRange]; } } return result; }