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:  苹果官方Demo:

- (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：