CODEWITHSUNDEEP
iosuitableview
Slinky
Slinky

Reputation: 5832

What's the Best Practice for Implementing Multi-section TableView

All,

I have about 3000 words with definitions that I am loading into a TableView. Right now, it's just a sorted list of words, sans the sections because I haven't added them yet.

Table View without Sections

I need to add sections to my TableView data (A,B,C ...) and there seems to be several ways to do this so before I jump into this I am looking for some confirmation or correction if I am going down the wrong rabbit hole.

Currently the data that the TableView reads is stored as objects in an NSMutableArray per this code:

//AppDelegate.m
- (void)applicationDidFinishLaunching:(UIApplication *)application
{

 //...

NSMutableArray *wordArray = [[NSMutableArray alloc] init];

//Loop through result set from DB and populate objects
while([rs next]){


       [wordArray addObject:[Word wordWith:[rs stringForColumn:@"word"]
                                 Definition:[rs stringForColumn:@"definition"] 
                               SectionIndex:[rs stringForColumn:@"sectionIndex"]]];



   }
   MainViewController *mainViewController = 
   [[MainViewController alloc] initWithNibName:@"MainView" bundle:nil];

   mainViewController.listContent = wordArray;

   //...

 }

Each object has a section index value ([A-Z0-9]) so I already know which section each word goes in, I know what the sections need to be and I can easily derive a count of objects for each section. All the words have been sorted via SQL before the NSMutableArray was populated so that's already handled.

Can I create multiple sections with the one NSMutableArray or do I need to do something different?

Thanks

Upvotes: 0

Views: 401

Answers (2)

Ricky Helgesson
Ricky Helgesson

Reputation: 3586

I have found that you sometimes want to add sorting to your lists and then, another approach might be interesting. Put all your models (Word's in your example) in a dictionary with some unique value of the model as the key.

Implement a sorting method, that you run every time the underlying dictionary changes. The sorting method will use e.g. keysSortedByValueUsingComparator on the dictionary and supply a different blocks for different sort orders. Let the sorting method create section arrays and add keys in the arrays that corresponds to the keys in the dictionary.

You do not store anything twice and you get different sort orders by just providing different sort blocks (that can look at any properties of your model class).

Upvotes: 0

Ignacio Inglese
Ignacio Inglese

Reputation: 2605

You could store your words into arrays inside a NSDictionary holding keys for each letter.

Number of sections would return 

[[dictionary allKeys] count];

Title for section

NSArray * keys = [dictionary allKeys];
[keys objectAtIndex:sectionIdx]

Number of rows in section would return

NSArray * keys = [dictionary allKeys];
[(NSArray *)[dictionary objectForKey:[keys objectAtIndex:sectionIdx]] count];

Each word would be

NSArray * keys = [dictionary allKeys];
[(NSArray *)[dictionary objectForKey:[keys objectAtIndex:sectionIdx]] objectAtIndex:indexPath.row];

Upvotes: 1

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