#import "ViewController.h"
@interfaceViewController ()<UICollectionViewDataSource,UICollectionViewDelegate,UICollectionViewDelegateFlowLayout>
@end
@implementation ViewController
- (void)viewDidLoad {
[superviewDidLoad];
UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayoutalloc] init];
UICollectionView *collection = [[UICollectionViewalloc] initWithFrame:self.view.boundscollectionViewLayout:layout];//初始化，并设置布局方式
collection.backgroundColor = [UIColor whiteColor];
[collection registerClass:[UICollectionViewCellclass] forCellWithReuseIdentifier:@"cell"];//注册UICollectionViewCell，这是固定格式，也是必须要实现的
[collection registerClass:[UICollectionReusableViewclass] forSupplementaryViewOfKind:UICollectionElementKindSectionHeaderwithReuseIdentifier:@"headerView"];//注册头/尾视图，视图类型必须为UICollectionReusableView或者其子类，kind设置为UICollectionElementKindSectionHeader或者UICollectionElementKindSectionFooter，最后设置标识
collection.delegate = self;
collection.dataSource = self;
[self.view addSubview:collection];
}
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{
//设置组数，不写该方法默认是一组
return 4;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return 9;
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
staticNSString *identifier = @"cell";//注意，此处的identifier要与注册cell时使用的标识保持一致
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
cell.backgroundColor = [UIColor grayColor];
cell.layer.borderWidth = 0.5;
cell.layer.borderColor = [UIColorwhiteColor].CGColor;
return cell;
}
//设置头视图的尺寸，如果想要使用头视图，则必须实现该方法
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section{
return CGSizeMake(300, 30);
}
-(UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath{
//根据类型以及标识获取注册过的头视图,注意重用机制导致的bug
UICollectionReusableView *headerView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeaderwithReuseIdentifier:@"headerView"forIndexPath:indexPath];
headerView.backgroundColor = [UIColor brownColor];
for (UIView *view in headerView.subviews) {
[view removeFromSuperview];
}
UILabel *label = [[UILabel alloc] initWithFrame:headerView.bounds];
label.text = [NSString stringWithFormat:@"%zi组的头视图",indexPath.section];
[headerView addSubview:label];
label.textColor = [UIColor whiteColor];
return headerView;
}
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
NSLog(@"%zi组，%zi行",indexPath.section,indexPath.item);
}
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
//设置item尺寸
returnCGSizeMake(self.view.frame.size.width/3.0, 100);
}
-(UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
//设置组距离上向左右的间距
returnUIEdgeInsetsMake(0,0,0,0);
}
-(CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{
//两个item的列间距
return 0;
}
-(CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section{
//如果一组中有多行item，设置行间距
return 0;
}
- (void)didReceiveMemoryWarning {
[superdidReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end