本文主要是介绍UICollectionView学习，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
day14 UICollectionViewhttp://blog.csdn.net/eqera/article/details/8134986
1. 块状化布局tableView的实现（简易瀑布流）

-(UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (tableView==_tableView1) {
UITableViewCell*cell=[tableView dequeueReusableCellWithIdentifier:@"tableView1"];
if (!cell) {
cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"tableView1"];
}
cell.textLabel.text=self.dataArray1[indexPath.row];
return cell;
}else{
UITableViewCell*cell1=[tableView dequeueReusableCellWithIdentifier:@"tableView2"];
if (!cell1) {
cell1=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"tableView2"];
}
cell1.textLabel.text=self.dataArray2[indexPath.row];
return cell1;
}
}
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView==_tableView1) {
_tableView2.contentOffset=_tableView1.contentOffset;
}else{
_tableView1.contentOffset=_tableView2.contentOffset;
}
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return arc4random()%40+40;
}
UITableView UICollectionView
Section-header/footer Supplementary View
BackgroundView DecorationView
2. UICollectionView 集合视图介绍

UICollectionView常用代理方法
// 有多少个分区
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView;
// 每个分区有多少个cell[item]
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section；
// 每个cell是什么
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath;
// section的头和尾视图 supplementaryView
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath；
// 属于UICollectionViewFlowLayoutDelegate 每个cell的尺寸
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
// 点选一个cell的时候触发的方法
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
注：在UICollectionView中，不仅cell可以重用，Supplementary View和Decoration View也是可以并且应当被重用的。
Line spacing（每行的间距）
1、 可以进行全局配置,如下属性
@property(CGFloat) minimumLineSpacing
2、 也可以通过delegate对每一个section进行配置，如下代码
collectionView:layout:minimumLineSpacingForSectionAtIndex:
Inter cell spacing（每行内部cell item的间距）
1、 可以进行全局配置,如下属性
@property(CGFloat) minimumInteritemSpacing
2、 也可以通过delegate对每一个section进行配置，如下代码
collectionView:layout:minimumInteritemSpacingForSectionAtIndex:
项目实例1：

Step 1> 新建布局对象
// UICollectionViewLayout 集合视图的布局类，是一个抽象基类,一般使用它的子类实现对cell的布局
// UICollectionViewFlowLayout : UICollectionViewLayout 系统提供的，能够实现cell的网格布局
UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
[flowLayout setScrollDirection:UICollectionViewScrollDirectionVertical];
// 设置行间距
flowLayout.minimumLineSpacing = 10;
// 设置item之间间距，实际间隔需要根据item的size和edgesInsets的值来调节
flowLayout.minimumInteritemSpacing = 0;
Step 2> 新建collectionView，设置它的delegate和dataSource, 并把布局对象赋给它
_collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 64, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height-64) collectionViewLayout:flowLayout];
_collectionView.delegate = self;
_collectionView.dataSource = self;
[flowLayout release];
Step 3> 注册cell, 注册section的头视图和尾视图
[_collectionView registerNib:[UINib nibWithNibName:@"MyCell" bundle:nil] forCellWithReuseIdentifier:@"MyCell"];
// [_collectionView registerClass:[MyCell class] forCellWithReuseIdentifier:@"MyCell"];
// -- header view --
[_collectionView registerClass:[CustomView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"Header"];
// -- footer view --
[_collectionView registerClass:[CustomView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"Footer"];
Step 4> 实现delegate方法，dataSource方法以及布局layout方法
// 指定每一个item的大小
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
return CGSizeMake(170, 120);
}
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section{
// 如果垂直滚动 view的width与集合视图一致,需要设置高度
return CGSizeMake(30,30);
}
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section{
return CGSizeMake(30,30);
}
// UIEdgeInsets 描述的是一个视图相对于另一个视图上、左、下、右的距离
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
return UIEdgeInsetsMake(10,8,10,8);
}
3. 从网络上加载数据，贴到collectionView上
用AFNetworking从网络上获取数据，并把数据贴到collectionView上
#define kUrlString @"http://open.qyer.com/lastminute/get_lastminute_list?client_id=qyer_ios&client_secret=cd254439208ab658ddf9&v=1&track_user_id=&track_deviceid=E57D6014-1D9F-437C-B9E5-17CF697370FA&track_app_version=5.4.4&track_app_channel=App%20Store&track_device_info=iPhone7,1&track_os=ios%208.1&lat=40.033568&lon=116.358971&app_installtime=1421832230&page_size=20&is_show_pay=1&country_id=0&continent_id=0&max_id=0×=&product_type=0"


#import "RootViewController.h"
#import "DiscountCell.h"
#import "AFNetworking.h"
#define kUrlString @"http://open.qyer.com/lastminute/get_lastminute_list?client_id=qyer_ios&client_secret=cd254439208ab658ddf9&v=1&track_user_id=&track_deviceid=E57D6014-1D9F-437C-B9E5-17CF697370FA&track_app_version=5.4.4&track_app_channel=App%20Store&track_device_info=iPhone7,1&track_os=ios%208.1&lat=40.033568&lon=116.358971&app_installtime=1421832230&page_size=20&is_show_pay=1&country_id=0&continent_id=0&max_id=0×=&product_type=0"
@interface RootViewController () <UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout>
@property (nonatomic, retain) NSMutableArray *dataArray;
@property (nonatomic, retain) UICollectionView *collectionView;
@end
@implementation RootViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self addCollectionView];
[self fetchWebData];
}
- (void)addCollectionView {
UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
self.collectionView = [[[UICollectionView alloc]initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height) collectionViewLayout:flowLayout] autorelease];
_collectionView.delegate = self;
_collectionView.dataSource = self;
[self.view addSubview:_collectionView];
[_collectionView registerNib:[UINib nibWithNibName:@"DiscountCell" bundle:nil] forCellWithReuseIdentifier:kDiscountCellID];
}
- (void)fetchWebData {
AFHTTPRequestOperationManager *manager =[AFHTTPRequestOperationManager manager];
// 服务端的content-Type 为application/json时，可以不写acceptContentTypes
// manager.responseSerializer.acceptableContentTypes
[manager GET:kUrlString parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
if (responseObject) {
NSArray *dataArr = responseObject[@"data"];
for (NSDictionary *subDict in dataArr) {
Discount *model = [[Discount alloc]init];
[model setValuesForKeysWithDictionary:subDict];
for (NSString *key in subDict) {
id obj = [subDict objectForKey:key];
[model setValue:obj forKey:key];
}
[_dataArray addObject:model];
}
[_collectionView reloadData];
}
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
}];
}
- (NSMutableArray *)dataArray {
if (_dataArray == nil) {
_dataArray = [[NSMutableArray alloc] init];
}
return _dataArray;
}
#pragma mark - <UICollectionViewDelegate, UICollectionViewDataSource>
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
//自动反选
[collectionView deselectItemAtIndexPath:indexPath animated:YES];
}
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{
return 1;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
DiscountCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kDiscountCellID forIndexPath:indexPath];
cell.discount = self.dataArray[indexPath.row];
return cell;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return self.dataArray.count;
}
#pragma mark - flow layout
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
return CGSizeMake(150, 180);
}
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
// return UIEdgeInsetsMake(5, 5, 5, 5);
return UIEdgeInsetsMake(5, 15, 5, 15);
}
#pragma mark - dealloc
- (void)dealloc {
[_dataArray release];
[_collectionView release];
[super dealloc];
}
@end
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4. XIB 加载viewController

- (void)loadView
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
关联ViewController和xib
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