iOS仿京东分类菜单之UICollectionView内容

在上《iOS仿京东分类菜单实例实现》已经实现了大部分主体的功能，本文是针对右边集合列表进行修改扩展，使它达到分组的效果，本文涉及到的主要是UICollectionView的知识内容，左边列表的实现见上一篇文章，先看实现的效果图：

一：实体的创建

1.1分组实体的创建(tagID跟左边表格进行关联，roomArray是存放房间的数组，也就是单元格的集合)

#import <Foundation/Foundation.h>

@interface rightModel : NSObject
//实体leftTageModel中的主键值
@property(assign,nonatomic)long tagID;
@property(assign,nonatomic)long roomStyleID;
@property(copy,nonatomic)NSString *roomStyleName;
//房间实体headRightModel的数组
@property(strong,nonatomic)NSMutableArray *roomArray;
@end

1.2房间实体的创建

#import <Foundation/Foundation.h>

@interface headRightModel : NSObject

@property(assign,nonatomic)long roomID;
@property(copy,nonatomic)NSString *roomName;
@property(copy,nonatomic)NSString *roomImageUrl;
@end

二：单元格的创建

#import <UIKit/UIKit.h>
#import "headRightModel.h"

@interface rightCollectionViewCell : UICollectionViewCell

@property(strong,nonatomic)headRightModel *curHeadRightModel;

+(CGSize)ccellSize;

@end

#import "rightCollectionViewCell.h"

@interface rightCollectionViewCell()
@property(strong,nonatomic)UIImageView *roomImageView;
@property(strong,nonatomic)UILabel *roomLabel;
@end

static const CGFloat collectionCellHeight=;
static const CGFloat labelHeight=;

@implementation rightCollectionViewCell

//这边很关键 CollectionViewCell重用
- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        if (self.roomImageView==nil) {
            self.roomImageView=[[UIImageView alloc] initWithFrame:CGRectMake(, , ([UIScreen mainScreen].bounds.size.width--*)/, collectionCellHeight-labelHeight)];
            self.roomImageView.contentMode=UIViewContentModeScaleAspectFill;
            self.roomImageView.clipsToBounds = YES;
            self.roomImageView.layer.masksToBounds = YES;
            self.roomImageView.layer.cornerRadius = 2.0;
            [self.contentView addSubview:self.roomImageView];
        }

        if (self.roomLabel==nil) {
            self.roomLabel=[[UILabel alloc]init];
            self.roomLabel.font=[UIFont systemFontOfSize:];
            self.roomLabel.textAlignment=NSTextAlignmentCenter;
            [self.roomLabel sizeToFit];
            [self.contentView addSubview:self.roomLabel];
            [self.roomLabel mas_makeConstraints:^(MASConstraintMaker *make) {
                make.top.mas_equalTo(self.roomImageView.mas_bottom).with.offset();
                make.centerX.mas_equalTo(self.roomImageView).with.offset();
                make.height.mas_equalTo(labelHeight);
            }];
        }
    }
    return self;
}

-(void)setCurHeadRightModel:(headRightModel *)curHeadRightModel
{
    _curHeadRightModel=curHeadRightModel;
    self.roomImageView.image=[UIImage imageNamed:_curHeadRightModel.roomImageUrl];
    self.roomLabel.text=_curHeadRightModel.roomName;
}

+(CGSize)ccellSize
{
    return CGSizeMake(([UIScreen mainScreen].bounds.size.width--*)/,collectionCellHeight);
}
@end

三：创建节点显示视图

#import <UIKit/UIKit.h>

@interface myHeadView : UICollectionReusableView

- (void) setLabelText:(NSString *)text;
@end

注意它是继承UICollectionReusableView

#import "myHeadView.h"

@interface myHeadView()
@property (strong, nonatomic) UILabel *label;
@end

@implementation myHeadView

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self)
    {
        self.label = [[UILabel alloc] init];
        //在这边调整它的位置
        self.label.frame=CGRectMake(, , , );
        self.label.font = [UIFont systemFontOfSize:];
        self.label.backgroundColor=[UIColor brownColor];
        self.label.textColor=[UIColor yellowColor];
        [self addSubview:self.label];
    }
    return self;
}

- (void) setLabelText:(NSString *)text
{
    self.label.text = text;
}

@end

四：创建测试数据跟初始化集合列表

- (void)viewDidLoad {
    [super viewDidLoad];

    //初始化
    self.view.backgroundColor=[UIColor whiteColor];
    self.dataList=[[NSMutableArray alloc]init];
    self.rightdataList=[[NSMutableArray alloc]init];
    self.allRightDataList=[[NSMutableArray alloc]init];
    self.isReturnLastOffset=YES;
    //是否允许右位保持滚动位置
    self.isKeepScrollState=YES;
    //测试数据
    for (int i=; i<; i++) {

        //左边列表数据
        leftTagModel *item=[[leftTagModel alloc]init];
        item.tagID=i;
        item.tagName=[NSString stringWithFormat:@"第%d层",i];
        [self.dataList addObject:item];

        //右边列表数据
        for (int j=; j<; j++) {
            rightModel *model=[[rightModel alloc]init];
            model.tagID=i;
            model.roomStyleID=j;
            model.roomStyleName=[NSString stringWithFormat:@"%d层类型%d",i,j];
            NSMutableArray *headRightModelArray=[[NSMutableArray alloc]init];
            for (int z=; z<; z++) {
                headRightModel *headrightModel=[[headRightModel alloc]init];
                headrightModel.roomID=z;
                headrightModel.roomName=[NSString stringWithFormat:@"%d类房间%d",j,z];
                headrightModel.roomImageUrl=[NSString stringWithFormat:@"room%d",z%];
                [headRightModelArray addObject:headrightModel];
            }
            model.roomArray=headRightModelArray;
            [self.allRightDataList addObject:model];
        }
    }

    //创建列表
    if (!_myTableView) {
        _myTableView = [[UITableView alloc] initWithFrame:CGRectMake(,,tableWidthSize, kScreenHeight) style:UITableViewStylePlain];
        _myTableView.backgroundColor=[UIColor grayColor];
        _myTableView.showsVerticalScrollIndicator = NO;
        _myTableView.showsHorizontalScrollIndicator=NO;
        _myTableView.dataSource = self;
        _myTableView.delegate = self;
        _myTableView.tableFooterView=[[UIView alloc]init];
        _myTableView.separatorColor= [UIColor colorWithRed:52.0f/255.0f green:53.0f/255.0f blue:61.0f/255.0f alpha:];
        [_myTableView registerClass:[leftTableCell class] forCellReuseIdentifier:NSStringFromClass([leftTableCell class])];

        if ([self.myTableView respondsToSelector:@selector(setLayoutMargins:)]) {
            self.myTableView.layoutMargins=UIEdgeInsetsZero;
        }
        if ([self.myTableView respondsToSelector:@selector(setSeparatorInset:)]) {
            self.myTableView.separatorInset=UIEdgeInsetsZero;
        }
        [self.view addSubview:_myTableView];
    }

    //创建集合表格
    if (!_myCollectionView) {
        UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
        self.myCollectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(tableWidthSize+leftMargin,, kScreenWidth-tableWidthSize-*leftMargin, kScreenHeight) collectionViewLayout:layout];
        self.myCollectionView.backgroundColor=[UIColor whiteColor];
        self.myCollectionView.showsHorizontalScrollIndicator=NO;
        self.myCollectionView.showsVerticalScrollIndicator=NO;
        [self.myCollectionView registerClass:[rightCollectionViewCell class] forCellWithReuseIdentifier:NSStringFromClass([rightCollectionViewCell class])];
        [self.myCollectionView registerClass:[myHeadView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:NSStringFromClass([myHeadView class])];
        self.myCollectionView.dataSource = self;
        self.myCollectionView.delegate = self;
        [self.view addSubview:self.myCollectionView];
    }

    self.selectIndex=;
    //默认选择第一个
    if (self.dataList.count>) {
        self.curSelectModel=[self.dataList objectAtIndex:self.selectIndex];
        [self.myTableView selectRowAtIndexPath:[NSIndexPath indexPathForRow:self.selectIndex inSection:] animated:YES scrollPosition:UITableViewScrollPositionTop];
        [self.myTableView reloadData];

        //右边数据加载
        [self predicateDataSoure];
    }
}

注意:关于节视图的注册

[self.myCollectionView registerClass:[myHeadView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:NSStringFromClass([myHeadView class])];

五：集合视图UICollectionViewDataSource, UICollectionViewDelegate的内容

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{
    return self.rightdataList.count;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
    rightModel * array=self.rightdataList[section];

    if (array.roomArray.count==) {
        return ;
    }
    else
    {
        return array.roomArray.count;
    }
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
    rightCollectionViewCell *ccell = [collectionView dequeueReusableCellWithReuseIdentifier:NSStringFromClass([rightCollectionViewCell class]) forIndexPath:indexPath];
    rightModel * array=self.rightdataList[indexPath.section];
    headRightModel *model=[array.roomArray objectAtIndex:indexPath.row];
    ccell.curHeadRightModel=model;
    return ccell;
}

-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section
{
    CGSize size = {,};
    return size;
}

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath{

    myHeadView *headView;
    rightModel * array=self.rightdataList[indexPath.section];
    if([kind isEqual:UICollectionElementKindSectionHeader])
    {
        headView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:NSStringFromClass([myHeadView class]) forIndexPath:indexPath];
        //别在这对headView坐标做处理
        [headView setLabelText:[NSString stringWithFormat:@"%@",array.roomStyleName]];
    }

    return headView;
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
    return [rightCollectionViewCell ccellSize];
}
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
    return UIEdgeInsetsZero;
}
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section{
    return ;
}
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{
    return ;
}

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{

}

注意：别在viewForSupplementaryElementOfKind，对myHeadView进行坐标的调整，因为它是全局的，会导致所有的节点都混在一起，记得设置它的节头大小，才会显示出来；

 六：扩展关于viewForSupplementaryElementOfKind，它可以设置节头跟节脚，下面引用网上一个比较全的说明

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath

为collection view添加一个补充视图(页眉或页脚)

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section

设定页眉的尺寸

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section

设定页脚的尺寸

- (void)registerClass:(Class)viewClass forSupplementaryViewOfKind:(NSString *)elementKind withReuseIdentifier:(NSString *)identifier

视图创建：

[self.myCollectionView registerClass:[MyHeadView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"hxwHeader"];
[self.myCollectionView registerClass:[MyHeadView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"hxwHeader"];

-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section
{
    CGSize size = {,};
    return size;
}

-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section
{
    CGSize size = {,};
    return size;
}

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
    MyHeadView *headView;

    if([kind isEqual:UICollectionElementKindSectionHeader])
    {
         headView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"hxwHeader" forIndexPath:indexPath];
        [headView setLabelText:[NSString stringWithFormat:@"section %d's header",indexPath.section]];
    }
    else if([kind isEqual:UICollectionElementKindSectionFooter])
    {
        headView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"hxwHeader" forIndexPath:indexPath];
        [headView setLabelText:[NSString stringWithFormat:@"section %d's footer",indexPath.section]];
    }
    return headView;
}

实例源代码下载地址