https://www.cnblogs.com/xubaoaichiyu/p/5294382.html
UICollectionView在眾多控件中也算是比較常用的了，像淘寶在瀏覽寶貝時采用的就是UICollectionView，對於UICollectionView－>UICollectionViewFlowLayout當然也是必不可少的了，還是老樣子結合代碼進行簡單介紹，首先看一下UICollectionView實現結果：
實現這些功能很簡單，代碼量極少，線看一下代碼，然后進行深入了解：
//
// ViewController.m
// CX－UICollentionVIew基礎
//
// Created by ma c on 16/3/19.
// Copyright © 2016年 xubaoaichiyu. All rights reserved.
//
#import "ViewController.h"
static NSString * identifier = @"cxCellID";
@interface ViewController ()<UICollectionViewDataSource>
@property (nonatomic, strong) UICollectionView * collectionView;
@end
@implementation ViewController
#pragma mark - set_and_get
-(UICollectionView *)collectionView{
if (!_collectionView) {
//自動網格布局
UICollectionViewFlowLayout * flowLayout = [[UICollectionViewFlowLayout alloc]init];
//網格布局
_collectionView = [[UICollectionView alloc]initWithFrame:self.view.frame collectionViewLayout:flowLayout];
//注冊cell
[_collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:identifier];
//設置數據源代理
_collectionView.dataSource = self;
}
return _collectionView;
}
#pragma mark - life
- (void)viewDidLoad {
[super viewDidLoad];
[self.view addSubview:self.collectionView];
}
#pragma mark - deleDate
//有多少的分組
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{
return 2;
}
//每個分組里有多少個item
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return 100;
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
//根據identifier從緩沖池里去出cell
UICollectionViewCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
cell.backgroundColor = [UIColor orangeColor];
return cell;
}
@end
介紹過最最基本的知識點之后，按着步驟來，進行進一步介紹。
UICollectionViewFlowLayout的使用讓UICollectionView更加豐富多彩，下面看一下使用UICollectionViewFlowLayout之后的效果吧－>
代碼－>
//
// ViewController.m
// CX－UICollentionVIew基礎
//
// Created by ma c on 16/3/19.
// Copyright © 2016年 xubaoaichiyu. All rights reserved.
//
#import "ViewController.h"
static NSString * identifier = @"cxCellID";
static CGFloat kMagin = 10.f;
static NSString * headIdentifier = @"cxHeadID";
@interface ViewController ()<UICollectionViewDataSource>
@property (nonatomic, strong) UICollectionView * collectionView;
@end
@implementation ViewController
#pragma mark - set_and_get
-(UICollectionView *)collectionView{
if (!_collectionView) {
//自動網格布局
UICollectionViewFlowLayout * flowLayout = [[UICollectionViewFlowLayout alloc]init];
CGFloat itemWidth = (self.view.frame.size.width - 4 * kMagin) / 3;
//設置單元格大小
flowLayout.itemSize = CGSizeMake(itemWidth, itemWidth / 0.618);
//最小行間距(默認為10)
flowLayout.minimumLineSpacing = 10;
//最小item間距（默認為10）
flowLayout.minimumInteritemSpacing = 10;
//設置senction的內邊距
flowLayout.sectionInset = UIEdgeInsetsMake(kMagin, kMagin, kMagin, kMagin);
//設置UICollectionView的滑動方向
flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
//sectionHeader的大小,如果是豎向滾動，只需設置Y值。如果是橫向，只需設置X值。
flowLayout.headerReferenceSize = CGSizeMake(100,0);
//網格布局
_collectionView = [[UICollectionView alloc]initWithFrame:self.view.frame collectionViewLayout:flowLayout];
//注冊cell
[_collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:identifier];
//注冊header
[_collectionView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:headIdentifier];
//設置數據源代理
_collectionView.dataSource = self;
}
return _collectionView;
}
#pragma mark - life
- (void)viewDidLoad {
[super viewDidLoad];
[self.view addSubview:self.collectionView];
}
#pragma mark - deleDate
//有多少的分組
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{
return 2;
}
//每個分組里有多少個item
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return 100;
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
//根據identifier從緩沖池里去出cell
UICollectionViewCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
cell.backgroundColor = [UIColor orangeColor];
return cell;
}
-(UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath{
//kind有兩種 一種時header 一種事footer
if (kind == UICollectionElementKindSectionHeader) {
UICollectionReusableView * header = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:headIdentifier forIndexPath:indexPath];
header.backgroundColor = [UIColor yellowColor];
return header;
}
return nil;
}
@end
靈活的是使用 UICollectionView＋UICollectionViewFlowLayout 會帶來更多的有趣的體驗，隨后我會介紹一些比較實用的實現。