kolinkrewinkel/KKGridView

###Deprecated In iOS 6, Apple has now created a first-party solution to what KKGridView tries to solve. See Session 219 from WWDC 2012 for more information.

###Overview High-performance iOS grid view (MIT license). Requirements: you need to build KKGridView with a compiler that supports Automatic Reference Counting. We know this stings at first, but we strongly believe that the future is better served by requiring this now. Moreover, the move to ARC improved KKGridView's performance greatly. Remember that your project need not use ARC to include KKGridView.

Contributing

If you see something you don't like, you are always welcome to submit it as an issue. But if you can find it in your heart, we'd be so grateful if you would fix it yourself and send us a pull request. We promise not to bite!

##Current Issues

Most features, bugs, and missing items for the project are in the Issues section. Currently, there are placement issues after inserting. We were initially going to fix these before public release, but instead decided to release now and allow outside contribution. Other than that, editing and selection are the only things that need work.

##Motivations

KKGridView was created in July 2011 for usage in a few of the apps I was working on. When I discovered that this would be both very difficult and time consuming, I sought out the help of Giulio Petek and Jonathan Sterling. Additionally, we brought on Kyle Hickinson, Matthias Tretter, and most recently, Peter Steinberger. We had all been frustrated by the existing grid view components; with this in mind, we set out to create the best grid view component available for iOS to-date.

##Goals

When we set out building this, we all had a few common things we knew we needed to focus on.

• Performance — 55+ FPS in the worst case.
• UITableView similarities — Strive to be as close to drop-in as possible.
• Feature completeness — As above, match the latest UITableView implementation in features; add anything else worthwhile.
• Solid codebase — We didn't want something that was inextensible and full of messy code.

##Project Integration

• Create a new workspace in Xcode in the same directory as your existing *.xcodeproj.
• Drag in your existing Xcode project.
• Locate your copy of KKGridView, drag KKGridView.xcodeproj into the workspace so that it stays at the top of the hierarchy, just like your original project.
• In the Build Phases section of your original project, link your project with libKKGridView.a.
• Now, simply import KKGridView just like an Apple framework:

#import <KKGridView/KKGridView.h>

• You can do this wherever necessary, though we think it's best to simply import in your prefix (.pch) file.

##Usage

KKGridViewController, like UITableViewController, can automatically instantiate a grid view for you. Simply subclass it and customize away.

As an alternative, one can perform custom instantiation, as shown below.

First, instantiate a grid view instance. Using the designated initializer and a _gridView ivar:

_gridView = [[KKGridView alloc] initWithFrame:self.view.bounds dataSource:self delegate:self];

Now, you can setup your default UIScrollView and UIView properties, since KKGridView inherits from said class.

_gridView.scrollsToTop = YES;
_gridView.backgroundColor = [UIColor darkGrayColor];
_gridView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

Metrics must also be set (automatic sizing may come in the future).

_gridView.cellSize = CGSizeMake(75.f, 75.f);
_gridView.cellPadding = CGSizeMake(4.f, 4.f);

Now, other properties available in the header file can be set.

_gridView.allowsMultipleSelection = NO;

UIView *headerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 50.f)];
headerView.backgroundColor = [UIColor redColor];
_gridView.gridHeaderView = headerView;
[headerView release] /* For the non-ARC users amongst us */

Finally, you can set the grid as your view.

self.view = _gridView;

Alternatively, you can add the grid to your view-hierarchy.

[self.view addSubview:_gridView];

###Data source methods:

- (NSUInteger)gridView:(KKGridView *)gridView numberOfItemsInSection:(NSUInteger)section
{
  return kCellCounts[section];
}

Optionally, you can specify how many section you would like in the grid. (Default is 1)

- (NSUInteger)numberOfSectionsInGridView:(KKGridView *)gridView
{
  return kNumSections;
}

The last required method is to return a cell, just like UITableView. We've made it easier on you, though. KKIndexPath works in just the same way as NSIndexPath, only -row is replaced with -index. KKGridViewCell, like UITableViewCell, is designed to be subclassed.*

- (KKGridViewCell *)gridView:(KKGridView *)gridView cellForItemAtIndexPath:(KKIndexPath *)indexPath
{
  KKGridViewCell *cell = [KKGridViewCell cellForGridView:gridView];
  cell.backgroundColor = [UIColor lightGrayColor];
  return cell;
}

There are no required delegate methods, though all that are implemented in UITableView will soon be available in KKGridView.