Skip to main content

How to share a variable between multiple Views/XIBs

Image
By User



I've read several similar threads, but can't seem to figure this out - sorry. I've got a project with multiple Views, including a ViewController, several "sub" views, and a NavigationController. I'd like to have an array that is accessible from any of the Views, so that I can populate a TableView or a TextField, etc. I'd like the array to be modifiable from any View that can access it.





Right now I have this in the xxAppDelegate.h file:







NSMutableArray *listOfHeadings;

@property (strong,nonatomic) NSMutableArray *listOfHeadings;







And in the xxAppDelegate.m file I populate the array:







listOfHeadings = [[NSMutableArray alloc] init];

[listOfHeadings addObject:@"Heading 0"];

[listOfHeadings addObject:@"Heading 1"];







But I can't seem to access the array from other .m files. How do I do this correctly?


Labels:

Comments

  1. Tips For AllJanuary 20, 2012 at 7:18 AM

    With the current design you have, you can get ahold of the AppDelegate pointer using:

    AppDelegate *dPtr = (AppDelegate *)[[UIApplication sharedApplication] delegate];


    Then you can access your array using the property:

    [dPtr.your_array objectAtIndex:i];


    But I would highly recommend using a Singleton design pattern to manage your global objects.

    ReplyDelete
  2. Tips For AllJanuary 20, 2012 at 7:18 AM

    While it is true that you could access your app delegate/root controller's property for the array, that would violate principles of encapsulation. Rather than define a single property that all your subview/controller classes will access, pass the array to each class that needs it (you'll still only have one array in memory, and each class will access the same array) at an appropriate time (eg, instantiation).

    Another option would be to create an application wide singleton class to provide the array to interested callers.

    ReplyDelete
  3. Tips For AllJanuary 20, 2012 at 7:18 AM

    Since you put your array in xxAppDelegate, you can access your array from any other class like this:

    #import "xxAppDelegate.h"
    //...
    NSMutableArray *array
    = [(xxAppDelegate *)[[UIApplication sharedApplication] delegate] listOfHeadings];

    ReplyDelete

Post a Comment

Popular posts from this blog

Why is this Javascript much *slower* than its jQuery equivalent?

By User
I have a HTML list of about 500 items and a "filter" box above it. I started by using jQuery to filter the list when I typed a letter (timing code added later): $('#filter').keyup( function() { var jqStart = (new Date).getTime(); var search = $(this).val().toLowerCase(); var $list = $('ul.ablist > li'); $list.each( function() { if ( $(this).text().toLowerCase().indexOf(search) === -1 ) $(this).hide(); else $(this).show(); } ); console.log('Time: ' + ((new Date).getTime() - jqStart)); } ); However, there was a couple of seconds delay after typing each letter (particularly the first letter). So I thought it may be slightly quicker if I used plain Javascript (I read recently that jQuery's each function is particularly slow). Here's my JS equivalent: document.getElementById('filter').addEventListener( 'keyup', function () { var jsStart = (new Date).getTime()...
3 comments
Read more

Is it possible to have IF statement in an Echo statement in PHP

By User
Thanks in advance. I did look at the other questions/answers that were similar and didn't find exactly what I was looking for. I'm trying to do this, am I on the right path? echo " <div id='tabs-".$match."'> <textarea id='".$match."' name='".$match."'>". if ($COLUMN_NAME === $match) { echo $FIELD_WITH_COLUMN_NAME; } else { } ."</textarea> <script type='text/javascript'> CKEDITOR.replace( '".$match."' ); </script> </div>"; I am getting the following error message in the browser: Parse error: syntax error, unexpected T_IF Please let me know if this is the right way to go about nesting an IF statement inside an echo. Thank you.
5 comments
Read more