@interface XCZCollectionHeader : UICollectionReusableView

#import "XCZCollectionsViewController.h"

#import "XCZCollectionViewCell.h"

#import "XCZCollectionHeader.h"

@interface XCZCollectionsViewController ()<UICollectionViewDataSource,UICollectionViewDelegate,UICollectionViewDelegateFlowLayout>

@end

@implementation XCZCollectionsViewController

- (void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view.

self.title = @"分类";

[self createCollectionView];

}

- (void)createCollectionView {

// 第一步：新建布局对象

UICollectionViewFlowLayout * layout = [[UICollectionViewFlowLayout alloc]init];

CGFloat padding = 10;

CGFloat itemW = (self.view.frame.size.width - 5 * padding)/4;

CGFloat itemH = itemW;

layout.itemSize = CGSizeMake(itemW, itemH);

// 头尾高度

layout.headerReferenceSize = CGSizeMake(0, 10);

// 最小间隔

// 对于垂直滚动，它是行间距

// 对于水平滚动，它是列间距

layout.minimumLineSpacing = 10;

// 内边距

layout.sectionInset = UIEdgeInsetsMake(10, 10, 10, 10);

// 集合视图，用于块状分布

// iOS6.0之后出现的视图

// 第二步，新建集合视图，关联布局对象

[self setAutomaticallyAdjustsScrollViewInsets:NO];

UICollectionView *collectionView = [[UICollectionView alloc]initWithFrame:CGRectMake(0, 64, self.view.frame.size.width, [[UIScreen mainScreen] bounds].size.height - 64) collectionViewLayout:layout];

// 第三步，注册cell, 注册追加视图(section的头和尾)

// 注册cell

[collectionView registerClass:[XCZCollectionViewCell class] forCellWithReuseIdentifier:@"MyCellID"]; // 复用标识，可随意写

// 注册supplementary view

// 第一个参数：注册的类

// 第二个参数：追加视图的类型 UICollectionElementKindSectionHeader  表示头，UICollectionElementKindSectionFooter表示尾 相当于tableView 中分区的headerView和footerView

// 第二个参数：复用标识

[collectionView registerClass:[XCZCollectionHeader class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"MySectionHeaderViewID"]; // 注册头

// 第四步，设置代理，并实现代理方法

collectionView.delegate = self;

collectionView.dataSource = self;

collectionView.backgroundColor = [UIColor whiteColor];

[self.view addSubview:collectionView];

}

#pragma mark - 实现代理方法

// 多少个分区

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {

return 4;

}

// 每个分区有多少cell(item)

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {

if (section == 0) {

return 7;

}else if (section == 1){

return 11;

}else if (section == 2){

return 12;

}else if (section == 3){

return 7;

}

return section;

}

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

// 每个cell是什么

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

XCZCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"MyCellID" forIndexPath:indexPath];

cell.imageView.image = [UIImage imageNamed:@"1"];

cell.textLabel.text = @"嘎嘎";

return cell;

}

// 头尾视图

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath {

// 根据是头视图还是尾视图作判断

XCZCollectionHeader *headerView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"MySectionHeaderViewID" forIndexPath:indexPath];

headerView.backgroundColor = [UIColor grayColor];

NSArray * arr = @[@"选集",@"主题",@"写景",@"节日"];

//    NSString *title = [[NSString alloc] initWithFormat:@"Recipe Group #%li",indexPath.section +1];

headerView.textLabel.text = arr[indexPath.section];

return headerView;

}

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{

NSLog(@"--%ld",(long)indexPath.row);

}

// 通过代理方法设置headerView的大小

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section {

return CGSizeMake(0, 26);

}