iOS UICollectionView详解

////  ViewC.m//  LessonUICollectionView////  Created by lanouhn on 14-9-16.//  Copyright (c) 2014年 [e-mail] 陈聪雷. All rights reserved.//#import "ViewC.h"#import "CLCollectionViewCell.h"#import "HeadView.h"#import "FootView.h"static NSString *cellIdentifier = @"cell";static NSString *headerIdentifier = @"header";static NSString *footerIdentifier = @"footer";@interface ViewC ()<UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout>@end@implementation ViewC- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];    if (self) {        // Custom initialization    }    return self;}- (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view.    self.view.backgroundColor = [UIColor lightGrayColor];    UICollectionViewFlowLayout *flowLayout= [[UICollectionViewFlowLayout alloc] init];    flowLayout.scrollDirection = UICollectionViewScrollDirectionVertical;//滚动方向    flowLayout.minimumLineSpacing = 10.0;//行间距(最小值)    flowLayout.minimumInteritemSpacing = 50.0;//item间距(最小值)    flowLayout.itemSize = CGSizeMake(50, 50);//item的大小    flowLayout.sectionInset = UIEdgeInsetsMake(10, 10, 10, 10);//设置section的边距    flowLayout.headerReferenceSize = CGSizeMake(320, 20);    flowLayout.footerReferenceSize = CGSizeMake(320, 20);    //第二个参数是cell的布局    UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, 320, 568) collectionViewLayout:flowLayout];    [flowLayout release];    collectionView.dataSource = self;    collectionView.delegate = self;    collectionView.backgroundColor = [UIColor orangeColor];    //1 注册复用cell(cell的类型和标识符)(可以注册多个复用cell, 一定要保证重用标示符是不一样的)注册到了collectionView的复用池里    [collectionView registerClass:[CLCollectionViewCell class] forCellWithReuseIdentifier:cellIdentifier];        //第一个参数:返回的View类型    //第二个参数:设置View的种类(header, footer)    //第三个参数:设置重用标识符    [collectionView registerClass:[HeadView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:headerIdentifier];    [collectionView registerClass:[FootView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:footerIdentifier];    [self.view addSubview:collectionView];    [collectionView release];}- (void)didReceiveMemoryWarning{    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}#pragma mark - UICollectionViewDataSource- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{    return 10;}- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{    return 10;}- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{    //2 从复用池中找cell(1:cell的标示符 2:indexPath决定系统用不用再给你创建cell, 不用创建的话, 就直接使用之前的cell)    CLCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];    cell.backgroundColor = [UIColor yellowColor];    cell.textLabel.text = [NSString stringWithFormat:@"%ld", (long)indexPath.row];    return cell;}- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath{    if (kind == UICollectionElementKindSectionHeader) {        HeadView *headerView = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:headerIdentifier forIndexPath:indexPath];        headerView.textLabel.text = @"让我组成头部!";        headerView.textLabel.textAlignment = NSTextAlignmentCenter;        headerView.textLabel.textColor = [UIColor whiteColor];        return headerView;    }    FootView *footerView = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:footerIdentifier forIndexPath:indexPath];    footerView.textLabel.text = @"让我组成尾部!";    footerView.textLabel.textAlignment = NSTextAlignmentCenter;    footerView.textLabel.textColor = [UIColor whiteColor];    return footerView;}#pragma mark - UICollectionViewDelegate- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{    NSLog(@"%d %d", indexPath.section, indexPath.row);}#pragma mark - UICollectionViewDelegateFlowLayout/*- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{}- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{    }- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section{    }- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{    }- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section{    }- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section{    } *//*#pragma mark - Navigation// In a storyboard-based application, you will often want to do a little preparation before navigation- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{    // Get the new view controller using [segue destinationViewController].    // Pass the selected object to the new view controller.}*/@end