DaiExpandCollectionView

Expand current selected item and catch users' eyes.

Demo

Installation

###CocoaPods DaiExpandCollectionView is available through CocoaPods.

• Add pod 'DaiExpandCollectionView' to your Podfile
• Run pod install
• Run open App.xcworkspace

###Manually Drap 4 source files under floder DaiExpandCollectionView\DaiExpandCollectionView\ to your project.

DaiExpandCollectionView.h
DaiExpandCollectionView.m
DaiExpandCollectionViewFlowLayout.h
DaiExpandCollectionViewFlowLayout.m

and then import the main header file：#import "DaiExpandCollectionView.h"

Overview

Unlike default UICollectionView can only display items with same fixed size, DaiExpandCollectionView can not only display items in two different sizes simultaneously but also change selected items with smooth animation.

How to use

###Step 1 : Init

DaiExpandCollectionView *daiExpandCollectionView = [DaiExpandCollectionView initWithFrame:self.view.bounds];
[daiExpandCollectionView registerClass:[ImageCollectionViewCell class] forCellWithReuseIdentifier:@"ImageCollectionViewCell"];
daiExpandCollectionView.expandDelegate = self;
[self.view addSubview:daiExpandCollectionView];

Note: Init DaiExpandCollectionView using [DaiExpandCollectionView initWithFrame:] instead of [[UICollectionView alloc] initWithFrame:collectionViewLayout:] which used by default UICollectionView.

Next, register UICollectionViewCell and then set up expandDelegate.

###Step 2 : Required delegate methods

There are two required methods in DaiExpandCollectionViewDelegate:

- (NSInteger)numberOfItemsInCollectionView:(UICollectionView *)collectionView;

Return the number of items (views) in the collection view. For example:

- (NSInteger)numberOfItemsInCollectionView:(UICollectionView *)collectionView {
     return 20;
}

means there are 20 items (views) in the collection view.

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath;

Return a UICollectionViewCell to be displayed at the specified index in the collection view. For example:

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
	static NSString *identifier = @"ImageCollectionViewCell";
	ImageCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
	cell.imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"%d.jpg", indexPath.row + 1]];
	return cell;
}

###Step 3 : Optional delegate methods

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndex:(NSInteger)index;

Return the index of current selected item. For example:

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndex:(NSInteger)index {
	NSLog(@"selected : %d", index);
}

Support

• iOS 7.0+
• iOS 8.0+ Tested
• iPhone / iPad
• Vertical only