Few Useful Objective-C Snippets for an iOS App

LAUNCH MAIL AND SEND AN EMAIL

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"mailto://mymail@myserver.com"]];

PREVENT SLEEP MODE

[UIApplication sharedApplication].idleTimerDisabled = YES;

STOP RESPONDING TO TOUCHES

[[UIApplication sharedApplication] beginIgnoringInteractionEvents];

RESUME RESPONDING TO TOUCHES

[[UIApplication sharedApplication] endIgnoringInteractionEvents];

DISPLAY AN ALERT WINDOW

UIAlertView* alert = [[[UIAlertView alloc] initWithTitle:@"Warning" message:@"too many alerts" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] autorelease];
[alert show]

DISPLAY THE NAME OF YOUR APPLICATION

self.title = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleName"];

CHANGE THE STYLE OF A NAVIGATION BAR

[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackOpaque];

GET THE CURRENT DATE AND TIME

NSCalendar *gregorian = [NSCalendar currentCalendar];
NSDateComponents *dateComponents = [gregorian components:(NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit) fromDate:[NSDate date]];

MAKE A VIBRATION

AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);

DISPLAY THE NUMBER OF LAUNCHES

NSUserDefaults *countDefaults;
int launchCount;

countDefaults = [NSUserDefaults standardUserDefaults];
launchCount = [countDefaults integerForKey:@"launchCount" ] + 1;
[countDefaults setInteger:launchCount forKey:@"launchCount"];
[countDefaults synchronize];

NSLog(@"Launch number: %i", launchCount);

CONFIGURING A UISCROLLVIEW

[scrollView setScrollEnabled:YES];
[scrollView setContentSize:CGSizeMake(320, 1400)];

SET TITLE OF A VIEW IN A UIVIEWCONTROLLER

viewController.title = @"Title Here...";

SET THE FONT AND SIZE OF A UITEXTVIEW

[thankYouTextView setFont:[UIFont fontWithName:@"Helvetica" size:16]];

SET THE FONT SIZE OF A UILABEL

[textView setFont:[UIFont fontWithName:@"Helvetica" size:16]];

PRESENTING A UIVIEWCONTROLLER

ViewController *viewController = [[ViewController alloc] init];
viewController = @"Title Here...";
[self.navigationController viewController animated:YES];

HIDING THE BACK BUTTON IN A NAVIGATION CONTROLLER

self.navigationItem.hidesBackButton = YES;

SET BACKGROUND OF VIEW

self.view.backgroundColor = [UIColor colorWithHue:1.0 saturation:0.0 brightness:0.6 alpha:1.0];

GIVE APP ICON A BADGE NUMBER

[UIApplication sharedApplication].applicationIconBadgeNumber = 10;

ALIGN UILABEL TEXT

titleLabel.textAlignment = UITextAlignmentCenter;

SET BACKGROUND OF TAB BAR

UIImage *tabBarBackground = [UIImage imageNamed:@"TabBarOverlay.png"];
[rootController.tabBar setBackgroundImage:tabBarBackground];

Credits: http://fuelyourcoding.com/