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：