iphone: Remember always small thing second

• 1.     Compare Null value that come from net.
• 2.     Image load from web.
• 3.     Navigate view from bottom.
• 4.     To dismiss this view.
• 5.  Get UDID of Apple Device.
• 6.     TAB base Application to come tab page instance of last visited page.
• 7.     Make Back Button on New Page rather with Back Name.
• 8.     Able Cancel button of ActionSheet on tab bar.
• 9.     Get Array from NSString.
• 10. How to make Shadow on UiLable. 
• 11. How to make image Corner round. 

Compare Null value that come from net:

if([[[data objectForKey:@"pic"] description] isEqualToString:@""])

or

if([data objectForKey:@"pic"] != [NSNull null])

Image load from web:

 NSData *receivedData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:URL]];

 UIImage  *image  = [[UIImage alloc] initWithData:receivedData] ;

Navigate view from bottom:

[self presentModalViewController:ObjChatting animated:YES];

To dismiss this view:

if(self.navigationController == nil)

          [self dismissModalViewControllerAnimated:YES];

Get UDID of Apple Device:

NSString *udid = [[UIDevice currentDevice] uniqueIdentifier];

NOTE: we can get other detail from UIDevice class.

TAB base Application to come tab page instance of last visited page:

- (void)viewDidDisappear:(BOOL)animated

{          

    if(self.navigationController.visibleViewController==self)

    {

      [self.navigationController popToViewController: [self.navigationController.viewControllers objectAtIndex:0] animated:YES];

    }      

}

Make Back Button on New Page rather with Back Name:

 UIBarButtonItem  *newBackButton = [[UIBarButtonItem alloc] initWithTitle: @"Back" style: UIBarButtonItemStyleBordered target: nil action: nil];

 [[self navigationItem] setBackBarButtonItem: newBackButton];

[newBackButton release];

 NOTE: Use in viewDidLoad in first page from where you write push statement.

Able Cancel button of ActionSheet on tab bar:

[actionSheet showInView:self.tabBarController.view];

NOTE: use when cancel button come over tabbar. (In this situation, cancel button will not work)

Get Array from NSString:

NSArray *arr = [str componentsSeparatedByString:@"\n"];

where str is @"One \n two \n three"

NOTE: Avoid to use NSMutableString, i had problem. 


How to make Shadow on UiLable:
label.shadowColor = [UIColor colorWithWhite:0.0 alpha:0.5];
or
lblname.shadowColor = [UIColor whiteColor];
with
lblname.shadowOffset = CGSizeMake(0.0, 1.0);

How to make image Corner round. 
For Button:
btnbottom4.imageView.layer.cornerRadius=15.0;
btnbottom4.imageView.layer.borderWidth=0.0;
btnbottom4.imageView.layer.borderColor=[[UIColor clearColor] CGColor];
For ImageView:
imageView.layer.cornerRadius=15.0; imageView.layer.borderWidth=0.0; imageView.layer.borderColor=[[UIColor clearColor] CGColor];