原博客网址：https://blog.csdn.net/mazegong/article/details/51247878
网格

import "RootViewController.h"

import "CustomCollectionViewCell.h"

@interface RootViewController ()<UICollectionViewDelegate,UICollectionViewDataSource,UICollectionViewDelegateFlowLayout>

@property (nonatomic,retain)NSDictionary *itemDic; // 承载一个item上面显示的图片和文字
@property (nonatomic,retain)NSMutableArray *allDataArray; // 成方所有的item上显示的内容，其实就是盛放小字典
@end

@implementation RootViewController

• (NSMutableArray *)allDataArray{
  if (!_allDataArray) {
  _allDataArray = [[NSMutableArray alloc]init];
  }return _allDataArray;
  }

• (void)viewDidLoad {
  [super viewDidLoad];
  for (int i = 1; i < 20; i++) {

    NSDictionary *itemDic = [[NSDictionary alloc] initWithObjectsAndKeys:
                               [NSString stringWithFormat:@"%d.jpg",i],@"imageName",
                               [NSString stringWithFormat:@"第%d个",i] ,@"textLable",
                               nil];
    [self.allDataArray addObject:itemDic];
  

  }

  self.navigationItem.title = @"github";
  // 由于初始化集合视图需要布局对象，所以我们才需要初始化布局对象，并且设置它的某些属性
  // 这个是系统提供的布局类，可以布局一些比较规则的布局。
  UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
  // 设置每个item的大小，
  flowLayout.itemSize = CGSizeMake(120, 160);
  // flowLayout.itemSize = CGSizeMake(CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame));
  // 设置列的最小间距
  flowLayout.minimumInteritemSpacing = 10;
  // 设置最小行间距
  flowLayout.minimumLineSpacing = 15;
  // 设置布局的内边距
  flowLayout.sectionInset = UIEdgeInsetsMake(15, 15, 15, 15);
  // 滚动方向
  flowLayout.scrollDirection = UICollectionViewScrollDirectionVertical;
  // flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal;

  UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:self.view.bounds collectionViewLayout:flowLayout];
  // 如果未设置背景颜色是黑色设置背景颜色
  collectionView.backgroundColor = [UIColor whiteColor];
  // 设置代理
  collectionView.delegate = self;
  collectionView.dataSource = self;
  // [collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"CELL"];
  [collectionView registerClass:[CustomCollectionViewCell class] forCellWithReuseIdentifier:@"CELL"];

  [self.view addSubview:collectionView];
  }

// 返回分区数

• (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{

  return 1;
  }

// 每个分区多少个item

• (NSInteger )collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{

  return _allDataArray.count;
  }

• (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
  // UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CELL" forIndexPath:indexPath];
  CustomCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CELL" forIndexPath:indexPath];
  // 取出每个item所需要的数据
  NSDictionary *dic = [_allDataArray objectAtIndex:indexPath.item];
  // 取出图片名称
  NSString *imageString = [dic objectForKey:@"imageName"];
  cell.imageView.image = [UIImage imageNamed:imageString];
  // 取出文字
  NSString *textString = [dic objectForKey:@"textLable"];
  cell.titleLabel.text = textString;
  cell.backgroundColor = [UIColor colorWithRed:arc4random()%256/256.0 green:arc4random()%256/256.0 blue:arc4random()%256/256.0 alpha:1];

return cell;

}

// 点击图片的方法

• (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
  NSLog(@"我点击了%ld图片！！！",indexPath.item + 1);

}

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }

/*

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

CustomCollectionViewCell.h中：

import <UIKit/UIKit.h>

@interface CustomCollectionViewCell : UICollectionViewCell
@property (nonatomic,retain)UIImageView *imageView; // 显示图片
@property (nonatomic,retain)UILabel *titleLabel; // 显示文字

@end

CustomCollectionViewCell.m中

import "CustomCollectionViewCell.h"

@implementation CustomCollectionViewCell

• (UIImageView *)imageView{
  if (!_imageView) {
  _imageView = [[UIImageView alloc] initWithFrame:self.viewForFirstBaselineLayout.bounds];
  [self.contentView addSubview:_imageView];
  }return _imageView;
  }

• (UILabel *)titleLabel{
  if (!_titleLabel) {
  _titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, CGRectGetHeight(self.bounds) - 30, CGRectGetWidth(self.bounds), 30)];
  [self.contentView addSubview:_titleLabel];
  }return _titleLabel;
  }
  @end