UICollectionView的使用小记录和一些说明

//
//  MallTestViewController.h
//  fitmiss
//
//  Created by bill on 16/6/28.
//  Copyright © 2016年 lear. All rights reserved.
//

#import "RootViewController.h"

@interface MallTestViewController : RootViewController

@end

//
//  MallTestViewController.m
//  fitmiss
//
//  Created by bill on 16/6/28.
//  Copyright © 2016年 lear. All rights reserved.
//

#import "MallTestViewController.h"

// 注意const的位置
static NSString *const cellId = @"cellId";
static NSString *const headerId = @"headerId";
static NSString *const footerId = @"footerId";

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

@end

@implementation MallTestViewController

- (void)viewDidLoad {
    [super viewDidLoad];

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

    UICollectionView *colView = [[UICollectionView alloc] initWithFrame:CGRectMake(, , [Function getScreenWidth], [Function getScreenHeight:self]) collectionViewLayout:layout];
    colView.backgroundColor = [UIColor grayColor];
    colView.dataSource = self;
    colView.delegate = self;
    [self.view addSubview:colView];

    // 注册cell、sectionHeader、sectionFooter
    [colView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:cellId];
    [colView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:headerId];
    [colView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:footerId];

}

- (NSArray *)loadData
{
    NSArray *arr = [NSArray arrayWithObjects:@"cell", @"cell2", @"cell3", @"cell4", @"cell5", @"cell6", @"cell7", @"cell8", @"cell9",nil];
    return arr;
}

#pragma mark - UICollectionViewDataSource
// 定义展示的Section的个数
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return ;
}

// 定义每个 UICollectionView 中展示的 UICollectionViewCell 的个数
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return [[self loadData] count];
}

// 每个 UICollectionView 展示的内容
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellId forIndexPath:indexPath];
    cell.backgroundColor = [UIColor redColor];
    return cell;
}

// 设置 UICollectionView 的段头段尾内容，和UITableView类似
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{

    if([kind isEqualToString:UICollectionElementKindSectionHeader])
    {
        UICollectionReusableView *headerView = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:headerId forIndexPath:indexPath];
        if(headerView == nil)
        {
            headerView = [[UICollectionReusableView alloc] init];
        }
        headerView.backgroundColor = [UIColor whiteColor];

        return headerView;
    }
    else if([kind isEqualToString:UICollectionElementKindSectionFooter])
    {
        UICollectionReusableView *footerView = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:footerId forIndexPath:indexPath];
        if(footerView == nil)
        {
            footerView = [[UICollectionReusableView alloc] init];
        }
        footerView.backgroundColor = [UIColor lightGrayColor];

        return footerView;
    }

    return nil;
}

// 是否可移动
- (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
}

// 处理移动
- (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath*)destinationIndexPath
{

}

#pragma mark - UICollectionViewDelegateFlowLayout

// 定义 UICollectionView 中 cell 的尺寸
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.section == ) {
        return CGSizeMake(, );
    }
    return CGSizeMake(, );
}

// 定义 UICollectionView 的 margin
-(UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
    return UIEdgeInsetsMake(, , , );
}

// 定义 UICollectionView 中上下两个 cell 的最小间距
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
{
    return .f;
}

// 定义 UICollectionView 中左右两个 cell 的最小间距
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section
{
    return .f;
}

// 定义 UICollectionView 头部的尺寸
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section{
    if (section==) {
        return CGSizeMake(, );
    }
    return CGSizeMake(, );
}

// 定义 UICollectionView 尾部的尺寸
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section
{
    return CGSizeMake(, );
}

#pragma mark - UICollectionViewDelegate

// UICollectionView被选中时调用的方法
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{

    NSLog(@"您点击了item:%@", [[self loadData] objectAtIndex:indexPath.row]);
    UICollectionViewCell *cell = (UICollectionViewCell *)[collectionView cellForItemAtIndexPath:indexPath];
    //cell.backgroundColor = [UIColor whiteColor];

}

// 返回这个UICollectionView是否可以被选择
-(BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
//    if (indexPath.row % 2)
//    {
//        return YES;
//    }
//    return NO;
}

// 开启突出某个内容
- (BOOL)collectionView:(UICollectionView *)collectionView shouldHighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
}

// 按下时处理内容 如:变色
- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
    cell.backgroundColor = [UIColor blueColor];
}

// 松开时处理内容 如:变色
- (void)collectionView:(UICollectionView *)collectionView didUnhighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
    cell.backgroundColor = [UIColor greenColor];
}

// 长按某item，弹出copy和paste的菜单
- (BOOL)collectionView:(UICollectionView *)collectionView shouldShowMenuForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
}

// 使copy和paste有效
- (BOOL)collectionView:(UICollectionView *)collectionView canPerformAction:(SEL)action forItemAtIndexPath:(NSIndexPath *)indexPath withSender:(nullable id)sender
{
    if ([NSStringFromSelector(action) isEqualToString:@"copy:"] || [NSStringFromSelector(action) isEqualToString:@"paste:"])
    {
        return YES;
    }

    return NO;
}

//处理copy和paste
- (void)collectionView:(UICollectionView *)collectionView performAction:(SEL)action forItemAtIndexPath:(NSIndexPath *)indexPath withSender:(nullable id)sender
{

//    if([NSStringFromSelector(action) isEqualToString:@"copy:"])
//    {
//        //        NSLog(@"-------------执行拷贝-------------");
//        [collectionView performBatchUpdates:^{
//            [_section0Array removeObjectAtIndex:indexPath.row];
//            [collectionView deleteItemsAtIndexPaths:@[indexPath]];
//        } completion:nil];
//    }
//    else if([NSStringFromSelector(action) isEqualToString:@"paste:"])
//    {
//        NSLog(@"-------------执行粘贴-------------");
//    }
}

@end