iOS UICollectionView简单使用

首先认识一下UICollectionView

 NS_CLASS_AVAILABLE_IOS(6_0) @interface UICollectionView : UIScrollView

UICollectionView 和 UICollectionViewController 类是iOS6 新引进的API，用于展示集合视图，布局更加灵活，可实现多列布局，用法类似于UITableView 和 UITableViewController 类。

使用UICollectionView 必须实现UICollectionViewDataSource,UICollectionViewDelegate,UICollectionViewDelegateFlowLayout这三个协议。

下面给出一些常用方法，具体的使用可以参考Demo:点我下载  苹果官方Demo:点我下载

 - (void)viewDidLoad
 {
     [super viewDidLoad];
     self.title = @"UICollectionView学习";

     //通过Nib生成cell，然后注册 Nib的view需要继承 UICollectionViewCell
     [self.collectionView registerNib:[UINib nibWithNibName:@"SQCollectionCell" bundle:nil] forCellWithReuseIdentifier:kcellIdentifier];

     //注册headerView Nib的view需要继承UICollectionReusableView
     [self.collectionView registerNib:[UINib nibWithNibName:@"SQSupplementaryView" bundle:nil] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:kheaderIdentifier];
     //注册footerView Nib的view需要继承UICollectionReusableView
     [self.collectionView registerNib:[UINib nibWithNibName:@"SQSupplementaryView" bundle:nil] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:kfooterIdentifier];
     //
     self.collectionView.allowsMultipleSelection = YES;//默认为NO,是否可以多选

 }

 - (void)didReceiveMemoryWarning
 {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }
 #pragma mark -CollectionView datasource
 //section
 - (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
 {
     return 2;
 }
 //item个数
 - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
 {
     return 6;

 }

 // The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:
 - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
 {
     //重用cell
     UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kcellIdentifier forIndexPath:indexPath];
     //赋值
     UIImageView *imageView = (UIImageView *)[cell viewWithTag:1];
     UILabel *label = (UILabel *)[cell viewWithTag:2];
     NSString *imageName = [NSString stringWithFormat:@"%ld.JPG",(long)indexPath.row];
     imageView.image = [UIImage imageNamed:imageName];
     label.text = imageName;

     cell.backgroundColor = [UIColor redColor];
     return cell;

 }
 // The view that is returned must be retrieved from a call to -dequeueReusableSupplementaryViewOfKind:withReuseIdentifier:forIndexPath:
 - (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath{

     NSString *reuseIdentifier;
     if ([kind isEqualToString: UICollectionElementKindSectionFooter ]){
         reuseIdentifier = kfooterIdentifier;
     }else{
         reuseIdentifier = kheaderIdentifier;
     }

     UICollectionReusableView *view =  [collectionView dequeueReusableSupplementaryViewOfKind :kind   withReuseIdentifier:reuseIdentifier   forIndexPath:indexPath];

     UILabel *label = (UILabel *)[view viewWithTag:1];
     if ([kind isEqualToString:UICollectionElementKindSectionHeader]){
         label.text = [NSString stringWithFormat:@"这是header:%d",indexPath.section];
     }
     else if ([kind isEqualToString:UICollectionElementKindSectionFooter]){
         view.backgroundColor = [UIColor lightGrayColor];
         label.text = [NSString stringWithFormat:@"这是footer:%d",indexPath.section];
     }
     return view;
 }
 //定义每个UICollectionViewCell 的大小
 - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
 {
     return CGSizeMake(60, 80);
 }
 //定义每个Section 的 margin
 -(UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
 {
     return UIEdgeInsetsMake(15, 15, 5, 15);//分别为上、左、下、右
 }
 //返回头headerView的大小
 -(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section{
     CGSize size={320,45};
     return size;
 }
 //返回头footerView的大小
 - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section
 {
     CGSize size={320,45};
     return size;
 }
 //每个section中不同的行之间的行间距
 - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
 {
     return 10;
 }
 //每个item之间的间距
 //- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section
 //{
 //    return 100;
 //}
 //选择了某个cell
 - (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
 {
     UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
     [cell setBackgroundColor:[UIColor greenColor]];
 }
 //取消选择了某个cell
 - (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath
 {
     UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
     [cell setBackgroundColor:[UIColor redColor]];
 }

效果图如下：