UICollectionViewCell 的正确写法

1.原生的

#import "WJBroadcastController.h"

static NSString * identifier = @"cxCellID";
static NSString * headIdentifier = @"headIdentifier";

@interface WJBroadcastController ()<UICollectionViewDelegate,UICollectionViewDataSource>

@property (nonatomic,strong)UICollectionViewFlowLayout  *collectionFlowLayout;
@property (nonatomic,strong)UICollectionView *collectionView;

@end

@implementation WJBroadcastController
- (UICollectionView *)collectionView{
    if (!_collectionView) {
        _collectionView = [[UICollectionView alloc] initWithFrame:CGRectNull collectionViewLayout:self.collectionFlowLayout];
        _collectionView.backgroundColor = QkColor;
        _collectionView.allowsMultipleSelection = NO;//是否支持多选
        _collectionView.delegate = self;
        _collectionView.dataSource = self;
    }
    return _collectionView;
    
}
// 可以自定义一些
-(UICollectionViewFlowLayout *)collectionFlowLayout{
    if (!_collectionFlowLayout) {
        _collectionFlowLayout = [[UICollectionViewFlowLayout alloc] init];
        _collectionFlowLayout.scrollDirection = UICollectionViewScrollDirectionVertical;
        _collectionFlowLayout.itemSize = CGSizeMake(100, 100);//每个item的大小
        //_collectionFlowLayout.minimumLineSpacing = 50;//行间距
        //_collectionFlowLayout.minimumInteritemSpacing = 10;//item之间的距离
        _collectionFlowLayout.sectionInset = UIEdgeInsetsMake(10, 10, 10, 10);//每组的位置间距
//        _collectionFlowLayout.headerReferenceSize = CGSizeMake(ScreenW, 80);
//        _collectionFlowLayout.footerReferenceSize = CGSizeMake(ScreenW, 40);
    }
    return _collectionFlowLayout;
}
- (void)viewDidLoad {
    [super viewDidLoad];
    [self.view addSubview:self.collectionView];
    [self.collectionView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.size.mas_equalTo(CGSizeMake(ScreenW, 500));
        make.centerX.equalTo(self.view);
        make.top.mas_equalTo(self.view);
    }];
    //注册collection 的cell
     [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:identifier];
    //注册collection 的header；
     [self.collectionView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:headIdentifier];
}

#pragma mark - cell代理
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{
    
    return 2;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
    return 9;
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
    UICollectionViewCell * cell  = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
   
    cell.backgroundColor = [UIColor colorWithRed:arc4random()%255/255.0 green:arc4random()%255/255.0 blue:arc4random()%255/255.0 alpha:1];
    for (UIView *view in cell.contentView.subviews) {
        if (view) {
          [view removeFromSuperview];
        }
    }
    
    
    return cell;
}
//选择了某个collection
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
    UICollectionViewCell *cell =  [collectionView cellForItemAtIndexPath:indexPath];
    [cell setBackgroundColor:[UIColor redColor]];
}
//取消某个collection
- (void)collectionView:(UICollectionView*)collectionView didDeselectItemAtIndexPath:(NSIndexPath*)indexPath

{
    UICollectionViewCell*cell = [collectionView cellForItemAtIndexPath:indexPath];
    [cell setBackgroundColor:[UIColor greenColor]];
    
}

#pragma mark - 头视图的代理
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath{
    UICollectionReusableView *header = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:headIdentifier forIndexPath:indexPath];
    header.backgroundColor = [UIColor yellowColor];
#warning message - 不同组的头视图(不一样)。
    // 解决头视图不一样的问题 添加多个头视图，以及设置他们的大小
    NSInteger index = indexPath.section;
    if (index == 0) {
      
    }
    if (index == 1) {
        
    }
    return header;
}
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section {
    //return CGSizeMake(头视图的宽, 头视图的高);
    return CGSizeMake(ScreenW, 50);
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section {
    
    //return CGSizeMake(尾视图的宽, 尾视图的高);
    return CGSizeMake(ScreenW, 50);
}

- (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

2.简单的分装一下。cell 以及头视图或者尾部试图

2.1 -----------------------cell

#define cellWidth self.contentView.bounds.size.width -10
#import "FirstMusicCollectionCell.h"


@interface FirstMusicCollectionCell ()

@property (nonatomic,strong)UIButton *butimage;
@property (nonatomic,strong)UILabel *lab1;
@property (nonatomic,strong)UILabel *lab2;

@end

@implementation FirstMusicCollectionCell

static FirstMusicCollectionCell *cell;

+ (instancetype)collection:(UICollectionView *)collectionView indexpath:(NSIndexPath *)indexpath{
    NSString *cellid = @"FirstMusicCollectionCell";
    [collectionView registerClass:[FirstMusicCollectionCell class] forCellWithReuseIdentifier:cellid];
    cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellid forIndexPath:indexpath];
    return cell;
}
- (instancetype)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        [self hg_setAllCornerWithCornerRadius:4];
        [self creatUI];
    }
    return self;
}
- (void)creatUI{
    UIButton *but = [[UIButton alloc] init];
    [self.contentView addSubview:but];
    but.userInteractionEnabled = NO;
    but.backgroundColor = [UIColor redColor];
    [but hg_setAllCornerWithCornerRadius:4];
    [but mas_makeConstraints:^(MASConstraintMaker *make) {
        make.size.mas_equalTo(CGSizeMake(cellWidth, cellWidth));
        make.centerX.equalTo(self.contentView);
        make.top.mas_equalTo(self.contentView).offset(5);
    }];
    UILabel *lab1 = [[UILabel alloc] init];
    [self.contentView addSubview:lab1];
    lab1.font = font(12);
    lab1.textAlignment = NSTextAlignmentLeft;
    [lab1 mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerX.equalTo(self.contentView);
        make.size.mas_equalTo(CGSizeMake(cellWidth, 15));
        make.top.mas_equalTo(but.mas_bottom);
    }];
    UILabel *lab2 = [[UILabel alloc] init];
    lab2.textColor = [UIColor colorTextGray];
    [self.contentView addSubview:lab2];
    lab2.font = font(12);
    lab2.textAlignment = NSTextAlignmentLeft;
    [lab2 mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerX.equalTo(self.contentView);
        make.size.mas_equalTo(CGSizeMake(cellWidth, 15));
        make.top.mas_equalTo(lab1.mas_bottom);
    }];
    _butimage = but;
    _lab1 = lab1;
    _lab2 = lab2;
}
- (void)setModel:(FirstMusicModel *)model
{
    _model = model;
//    [_butimage setImage:self.model.image];
    _lab1.text = self.model.text1;
    _lab2.text = self.model.text2;
}
- (void)setModel2:(FirstMusicListModel *)model2
{
    _model2 = model2;
//    [_butimage setImage:self.model2.image];
    _lab1.text = self.model2.text1;
    _lab2.text = self.model2.text2;
}
#pragma mark- 解决重用问题
//预防重用-- 目前没遇到问题
- (void)prepareForReuse {
    //NSLog(@"MyCollection9999999%s --- %@", __func__, self);
}

@end

2.2 头部试图 *********** 不要一个里面写好几个，分开写

//
//  FirstMusciHeader2.m
//  ParallelWorld
//
//  Created by 齐凯 on 2018/10/12.
//  Copyright © 2018年 Mac. All rights reserved.
//

#import "FirstMusciHeader2.h"
@interface FirstMusciHeader2()
@property (nonatomic,strong)UIView *view1;
@end

@implementation FirstMusciHeader2
static FirstMusciHeader2 *header;

+ (instancetype)collectionResuableView:(UICollectionView *)collectionView indexpath:(NSIndexPath *)indexPath{
    NSString *cellID = @"FirstMusciHeader2";
    //注册collection 的header；
    [collectionView registerClass:[FirstMusciHeader2 class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:cellID];
    header = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:cellID forIndexPath:indexPath];
    return header;
}
- (instancetype)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        [self creatUI];
        self.backgroundColor = [UIColor blackColor];
    }
    return self;
}
- (void)creatUI{
    
    [self view1];
}

- (UIView *)view1{
    if (!_view1) {
        _view1 = [[UIView alloc] initWithFrame:CGRectMake(0, 40, ScreenW, 40)];
        _view1.backgroundColor = [UIColor whiteColor];
        [self addSubview:self.view1];
        UILabel *lab = [[UILabel alloc] init];
        lab.text = @"热门单曲";
        lab.textAlignment = NSTextAlignmentCenter;
        lab.font = [UIFont systemFontOfSize:17];
        [_view1  addSubview:lab];
        [lab mas_makeConstraints:^(MASConstraintMaker *make) {
            make.size.mas_equalTo(CGSizeMake(200, 40));
            make.center.equalTo(self.view1);
        }];
        UIButton *but = [[UIButton alloc] init];
        [but addTarget:self action:@selector(butNextBtn) forControlEvents:(UIControlEventTouchUpInside)];
        [_view1 addSubview:but];
        [but setImage:@"更多_28"];
        [but mas_makeConstraints:^(MASConstraintMaker *make) {
            make.size.mas_equalTo(CGSizeMake(30, 30));
            make.centerY.equalTo(self.view1);
            make.right.mas_equalTo(self.view1);
        }];
    }
    return _view1;
}
#pragma mark - 点击事件
- (void)butNextBtn{
    //更多
    
}
@end