#import "ViewController.h"

#import "CollectionReusableView.h"

#define SCREEN_WIDTH   [UIScreen mainScreen].bounds.size.width

#define SCREEN_HEIGHT

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

@end

@implementation

- (void)viewDidLoad {

    [superviewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

//flowLayout 控制UICollectionView佈局

UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayoutalloc]init];

//section內建大小

    flowLayout.sectionInset = UIEdgeInsetsMake

//預設最小為10 如果比10小需要重新賦值

//    flowLayout.minimumInteritemSpacing = 5;

//行間距

    flowLayout.minimumLineSpacing = 5;

//item大小如果只有一種size 不適用代理方法返回大小

//    flowLayout.itemSize = CGSizeMake((SCREEN_WIDTH - 30)/ 3, 200);

//預估算,節省時間

//多種item大小 使用estimatedItemSize提高程式碼運算效率,提高流暢度

//flowLayout.estimatedItemSize = CGSizeMake(((SCREEN_WIDTH - 20) + (SCREEN_WIDTH - 30)/3)/2, 200);

//設定header大小

    flowLayout.headerReferenceSize = CGSizeMake(SCREEN_WIDTH, 50);

//    flowLayout.sectionHeadersPinToVisibleBounds = YES;

//    flowLayout.footerReferenceSize = CGSizeMake(SCREEN_WIDTH, 50);

    UICollectionView *collection = [[UICollectionView alloc]initWithFrame:self.view.frame collectionViewLayout:flowLayout];

//設定允許多選

    collection.allowsMultipleSelection = YES;

//籤代理

    collection.delegate = self;

    collection.dataSource = self;

    collection.backgroundColor = [UIColor whiteColor];

//註冊

    [collection registerClass:[UICollectionViewCellclass] forCellWithReuseIdentifier:@"UICollectionViewCell"];

    [self.view addSubview:collection];

//頭部區域底部區域同cell一樣遵循重用機制

    [collection registerClass:[CollectionReusableViewclass] forSupplementaryViewOfKind:UICollectionElementKindSectionHeaderwithReuseIdentifier:@"UICollectionReusableView"];

    [collection registerClass:[UICollectionReusableViewclass] forSupplementaryViewOfKind:UICollectionElementKindSectionFooterwithReuseIdentifier:@"UICollectionReusable"];

}

#pragma mark - collection delegate/dataSource

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

    return 3;

}

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

    if (section == 0) {

        return 1;

    }else if (section == 1){

        return 4;

    }else{

        return 5;

    }

}

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

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

    if (cell.isSelected) {

        cell.backgroundColor = [UIColor grayColor];

    }else{

        cell.backgroundColor = [UIColor orangeColor];

    }

    return cell;

}

#pragma mark - 

//collView學名是集合檢視  tableView是表檢視

//collView中的foot header 是曽補檢視

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

if (kind == UICollectionElementKindSectionHeader ) {

CollectionReusableView *reusableView = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@"UICollectionReusableView"forIndexPath:indexPath];

        reusableView.backgroundColor = [UIColor redColor];

        return reusableView;

    }else{

UICollectionReusableView *reusable = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@"UICollectionReusable"forIndexPath:indexPath];

        reusable.backgroundColor = [UIColor blackColor];

        return reusable;

    }

}

//判斷分割槽,可以直接籤代理或者進入flowlayout裡直接複製方法

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{

    if (indexPath.section == 0) {

         NSLog(@"1111111");

        return CGSizeMake(375, 200);

    }else  if (indexPath.section == 1){

        return CGSizeMake(SCREEN_WIDTH / 2 - 50 , 100);

    }else{

        return CGSizeMake(SCREEN_WIDTH - 20 , 200);

    }

}

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

//根據idenxPath獲取對應的cell

    UICollectionViewCell *cell =  [collectionView cellForItemAtIndexPath:indexPath];

    cell.backgroundColor = [UIColor grayColor];

}

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

    UICollectionViewCell *cell =  [collectionView cellForItemAtIndexPath:indexPath];

    cell.backgroundColor = [UIColor orangeColor];

}