**门掩黄昏，无计留春住。**<卡比兽>
@interface ViewController () <UICollectionViewDataSource,UICollectionViewDelegate>
// 对其操作遵循的两个协议
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
//第一步:创建UICollectionViewFlowLayout 它是专门给collectionView布局
UICollectionViewFlowLayout *flowLayout =[UICollectionViewFlowLayout new];
//第二步: 给定item的大小
flowLayout.itemSize=CGSizeMake(60, 60);
//第三步: 设定每两个item的最小的间隔(垂直滚动)
flowLayout.minimumInteritemSpacing=10;
//每行之间的最小间隔 (水平滚动)
flowLayout.minimumLineSpacing=40;
//第四步: 设置滚动的方向 (垂直)
flowLayout.scrollDirection=UICollectionViewScrollDirectionVertical;
//布局头部视图尺寸
flowLayout.headerReferenceSize=CGSizeMake(80, 80);
//布局尾部视图尺寸
flowLayout.footerReferenceSize=CGSizeMake(80, 80);
//视图的内边距
flowLayout.sectionInset = UIEdgeInsetsMake(10, 10, 10, 10);
//布局UICollectionView
UICollectionView *collection = [[UICollectionView alloc]initWithFrame:[UIScreen mainScreen].bounds collectionViewLayout:flowLayout];
//设置代理
collection.delegate=self;
collection.dataSource=self;
collection.backgroundColor=[UIColor redColor];
[self.view addSubview:collection];
//注册cell
[collection registerClass:[FirstCollectionViewCell class] forCellWithReuseIdentifier:@"cell"];
//注册头部视图
[collection registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"headerView"];
//注册尾部视图
[collection registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"footerView"];
}
#pragma mark -------数据源 (必须实现的方法 )
//设置分区下item数
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return 20;
}
//返回collectionView的方法
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
FirstCollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
cell.photoImage.image = [UIImage imageNamed:@"3.jpg"];
return cell;
}
//@optional
//设置分区数
-(NSInteger )numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 4;
}
//返回头部和尾部视图的样式
-(UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
//需要判断返回的是头部还是尾部视图
if ([kind isEqualToString:UICollectionElementKindSectionHeader])
{
//初始化头部视图
UICollectionReusableView *headerView=[collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"headerView" forIndexPath:indexPath];
//设置头部视图样式
headerView.backgroundColor=[UIColor cyanColor];
return headerView;
}else
{
UICollectionReusableView *footerView=[collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"footerView" forIndexPath:indexPath];
footerView.backgroundColor = [UIColor greenColor];
return footerView;
}
return nil;
}
//选择item时 ,会触发的方法
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
//indexPath 是由 section和item 组成
if (indexPath.item == 0 && indexPath.section == 0) {
SecondViewController *secondVC=[SecondViewController new];
点击第一区第一个单元cell跳转到 secondVC
[self.navigationController pushViewController:secondVC animated:YES];
}else if (indexPath.item == 1 && indexPath.section == 0)
{
ThirdViewController *thirdVC=[ThirdViewController new];
点击第一区第二个单元cell跳转到 thirdVC
[self.navigationController pushViewController:thirdVC animated:YES];
}
}
