[iphone] Great UIKit/Objective-C code snippets

1 Answers

  1. Display an alert window:

    UIAlertView* alert = [[[UIAlertView alloc] initWithTitle:@"Warning" message:@"too many alerts" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] autorelease];
    [alert show] 
  2. Get the path to the Documents folder:

    NSArray*  paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString* documentsDirectory = [paths objectAtIndex:0];
  3. Push another view controller onto the Navigation Bar:

    [self.navigationController pushViewController:anotherVC animated:YES];
  4. Fade away a UIView by animating the alpha down to 0:

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:1];  // fade away over 1 seconds
    [aView setAlpha:0]; 
    [UIView commitAnimations];                      
  5. Get the name of the app

    self.title = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleName"];
  6. Change the status bar to black

    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackOpaque];
  7. Change the style of the navigation bar (from in a view controller):

    self.navigationController.navigationBar.barStyle = UIBarStyleBlack;
  8. Save a NSString into NSUserDefaults:

    NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
    [defaults setObject:loginName forKey:kUserLoginName];
  9. Get an NSString from NSUserDefaults:

    NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];

    NSString* loginName = [defaults stringForKey:kUserLoginName];

  10. Check to make sure an objects support a method before calling it:

    if ([item respondsToSelector:@selector(activateBOP:)]) {
        [item activateBOP:closeBOP];
  11. Log the name of the class and function:

    NSLog(@"%s", __PRETTY_FUNCTION__);
  12. Add rounded corners and/or a border around any UIView item (self)

    self.layer.borderColor  = [UIColor whiteColor].
    self.layer.cornerRadius = 8;     // rounded corners
    self.layer.masksToBounds = YES;  // prevent drawing outside border
  13. Open Google Maps app with directions between two lat/long points

    NSString *urlString = [NSString stringWithFormat:@"http://maps.google.com/maps?saddr=%f,%f&daddr=%f,%f&dirflg=d", start.latitude, start.longitude, finish.latitude, finish.longitude];
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:urlString]]; 

New to Objective-C iPhone/iPod touch/iPad development, but I'm starting to discover lots of power in one-liners of code such as this:

[UIApplication sharedApplication].applicationIconBadgeNumber = 10;

Which will display that distinctive red notification badge on your app iphone with the number 10.

Please share you favorite one or two-liners in Objective-C for the iPhone/iPod touch/iPad here. PUBLIC APIs ONLY.

Make the device vibrate:


Open the Messages app with a specific phone number:

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"sms:123456789"]];

Stop responding to touch events:

[[UIApplication sharedApplication] beginIgnoringInteractionEvents];

Start responding again:

[[UIApplication sharedApplication] endIgnoringInteractionEvents];

And finally, the single line of code browser:

[[webView mainFrame] loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString: [urlText stringValue]]]];