UI1_UICollectionView

//  AppDelegate.m

//  UI1_UICollectionView

//

//  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

//  UI1_UICollectionView

//

//  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

//  UI1_UICollectionView

//

//  Created by zhangxueming on 15/7/16.

//  Copyright (c) 2015年 zhangxueming. All rights reserved.

//



#import "ViewController.h"



//重用标志符

#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.

    //1.创建数据源

    [self createDataList];

    //2.创建UI

    [self createCollectionView];

    //3.遵守协议,设置代理

}



//创建数据源

- (void)createDataList

{

    _dataList = [NSMutableArray array];

    for (int i=0; i<20; i++) {

        NSString *str = [NSString stringWithFormat:@"第%d个网格", i+1];

        [_dataList addObject:str];

    }

}



//创建UI



- (void)createCollectionView

{

    //第一个参数: collectionView 的位置

    //第二个参数: 布局对象, UICollectionViewLayout类(子类)的对象

    //规则布局

    //UICollectionViewFlowLayout:UICollectionViewLayout

    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];

    //上下左右边界的距离top, left, bottom, right

    layout.sectionInset  = UIEdgeInsetsMake(5, 5, 5, 5);

    //设置cell的大小

    layout.itemSize = CGSizeMake(180, 100);

    

    //设置横向的最小距离

    layout.minimumInteritemSpacing = 5;

    //设置竖向的最小距离

    layout.minimumLineSpacing = 10;

    

    _collectionView = [[UICollectionView alloc] initWithFrame:self.view.frame collectionViewLayout:layout];

    

    //设置代理

    _collectionView.delegate = self;

    _collectionView.dataSource  = self;



    //注册cell

    //第一个参数:cell的类型

    //第二个参数:cell的重用标识符

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

    _collectionView.backgroundColor = [UIColor cyanColor];

    [self.view addSubview:_collectionView];

}





#pragma mark ---collectionView代理---



//返回分区的个数

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView

{

    return 1;

}



//返回每个分区有多少个cell

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section

{

    return _dataList.count;

}



//返回cell



- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath

{

    //UITableView : indexPath --> section row

    //UICollectionView: indexPath --> section item

    //从重用队列中取出cell

    UICollectionViewCell  *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kCellReuseId forIndexPath:indexPath];

    

    cell.backgroundColor = [UIColor yellowColor];

    

    //移除cell.contentView 的子视图

    for (UIView *view in cell.contentView.subviews) {

        [view removeFromSuperview];

    }

    

    //在cell上显示内容

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 30, 180, 40)];

    label.text = _dataList[indexPath.item];

    label.textAlignment = NSTextAlignmentCenter;

    [cell.contentView addSubview:label];

    

    return cell;

}







- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}



@end