UI2_UICollectionViewPicture

//  AppDelegate.m
//  UI2_UICollectionViewPicture
//
//  Created by zhangxueming on 15/7/16.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import "AppDelegate.h"
#import "ViewController.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    ViewController *root = [[ViewController alloc] init];
    UINavigationController *nav =[[UINavigationController alloc] initWithRootViewController:root];
    self.window.rootViewController = nav;
    self.window.backgroundColor = [UIColor whiteColor];

    return YES;
}

//  ViewController.h
//  UI2_UICollectionViewPicture
//
//  Created by zhangxueming on 15/7/16.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@end

//
//  ViewController.m
//  UI2_UICollectionViewPicture
//
//  Created by zhangxueming on 15/7/16.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import "ViewController.h"

#define kCellReuseId @"cellID"

@interface ViewController ()<UICollectionViewDataSource, UICollectionViewDelegate>
{
    UICollectionView *_collectionView;
    NSMutableArray *_dataList;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    //创建数据源
    [self createDataList];
    //创建UI
    [self createUI];
    //代理
    self.navigationController.navigationBar.barTintColor = [UIColor redColor];
}

- (void)createDataList
{
    _dataList = [NSMutableArray array];
    for (int i=0; i<10; i++) {
        NSString *name = [NSString stringWithFormat:@"superCar%i", i];
        NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:@"png"];
        UIImage *image = [UIImage imageWithContentsOfFile:path];
        [_dataList addObject:image];
    }
}

//创建UI

- (void)createUI
{
    //创建布局对象
    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
    //上下左右边距
    layout.sectionInset = UIEdgeInsetsMake(10, 10, 10, 10);
    //cell的大小
    layout.itemSize = CGSizeMake(150, 100);
    //cell横向间距
    layout.minimumInteritemSpacing = 20;
    //cell纵向间距
    layout.minimumLineSpacing = 30;
    //创建collectionView
    _collectionView = [[UICollectionView alloc] initWithFrame:self.view.frame collectionViewLayout:layout];
    _collectionView.backgroundColor = [UIColor whiteColor];
    //设置代理
    _collectionView.delegate = self;
    _collectionView.dataSource = self;

    //注册cell

    [_collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:kCellReuseId];

    [self.view addSubview:_collectionView];
}

#pragma mark ---delegate---

//返回分区个数
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}

//返回分区cell 的个数

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return _dataList.count;
}

//返回cell

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell  = [collectionView dequeueReusableCellWithReuseIdentifier:kCellReuseId forIndexPath:indexPath];

    for (UIView *view in cell.contentView.subviews) {
        [view removeFromSuperview];
    }

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 150, 100)];
    imageView.image = _dataList[indexPath.item];
    [cell.contentView addSubview:imageView];

    return cell;
}

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

@end