• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Re: Newbie Question: Multidimensional NSMutableArray Creation
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Newbie Question: Multidimensional NSMutableArray Creation


  • Subject: Re: Newbie Question: Multidimensional NSMutableArray Creation
  • From: Stefan Arentz <email@hidden>
  • Date: Mon, 14 May 2001 12:04:04 +0200

On Mon, May 14, 2001 at 07:35:19PM +1000, William Jamieson wrote:
> Hello All,
>
> I am new to java and java-cocoa programming and I have been trying to figure
> out a workaround to create a multidimensional NSMutableArray.
>
> I have a NSTableView (with 4 columns and a variable number of rows) in a
> window with a custom class as its DataSource. What I really want to do is
> have an Parent NSMutableArray that is an array of Rows (also
> NSMutableArrays). Thus creating a (workaround) multidimensional Array
> (similar to a String[][] in java).
>
> When I need to access cell data (eg. Row 3, Column 2) from the Array System
> I can set a variable to the row 3 object (an NSMutableArray). I can then get
> the 2nd object in the Row which represents the 2nd Column Data for that row.
>
> If I need to replace a cell's data (eg. Row 3, Column 2) from the Array
> System I can set a variable (eg. 'myExtractedRow') to the row 3 object (an
> NSMutableArray). I can then replace the 2nd object in the Row which
> represents the 2nd Column Data for that row. Following this can replace the
> 3rd object in the parent array with the new 'myExtractedRow' Array'.
>
> Qusetions:
> 1 . How do I create an NSMutableArray of NSMutableArrays (if this is even
> possible)?

I have not used Cocoa/Java, so here's a twoliner in objc. You should be
able to translate that into java...

NSMutableArray *theRows = [[NSMutableArray array] retain];
[theRows addObject: [NSMutableArray array: 3]];

This is all pretty basic stuff.

> 2. How do I set up the parent NSMutableArray and and set up the methods to
> add and remove rows (also NSMutableArray's) from the parent array?

This is all documented in the NSArray and NSMutableArray documentation.

> 3. Is there a better/easier way to do this other than what I am proposing?

Well. It works, but is very expensive if you have many rows. Why don't you
create a simple object to store your data? That will be much faster; you can
access the right data for the request row/column much faster and you will not
have the overhead of arrays and many calls across the ObjC/Java bridge.

Stefan


  • Follow-Ups:
    • Re: Newbie Question: Multidimensional NSMutableArray Creation
      • From: Cyril Godefroy <email@hidden>
References: 
 >Newbie Question: Multidimensional NSMutableArray Creation (From: William Jamieson <email@hidden>)

  • Prev by Date: Newbie Question: Multidimensional NSMutableArray Creation
  • Next by Date: Re: Newbie Question: Multidimensional NSMutableArray Creation
  • Previous by thread: Newbie Question: Multidimensional NSMutableArray Creation
  • Next by thread: Re: Newbie Question: Multidimensional NSMutableArray Creation
  • Index(es):
    • Date
    • Thread