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自定义轮播图 自定义集合控件的实现

作者:ONEDAYTIME  发布日期:2016-01-05 19:28:45
Tag标签:控件  
  • 首先声明本篇博客是个人原创,绝非抄袭。

    自定义实现轮播图

    轮播图一般实现在一款App的首页的最上部分,能够来回滚动的图片,通常这些图片都对应一个网络Url ,用户点击的时候,能够跳转到对应的UIwebView页面。轮播图也可以使用在用户引导页面,只不过这时候轮播图的大小是全屏的,用户可以在轮播图上放一些控件,用来收集用户的信息,当用户进入程序的时候,可以根据这些信息,加载相应的版块内容,或者推荐相应的推送。轮播图也可以在相框的程序中用到,也可以在新闻类App中对应一个专题的整页的滑动,总之轮播图增添了App的用户体验效果,是必不可少的一个技术实现。

    本文的轮播图采用工具:

    UIScrollView(用于实现轮播效果)、UILabel(用于显示当前是第几张)、NSTimer(用于实现自动轮播)采用封装的思想,降低耦合度,将该功能组件化。

    目前实现的功能相对来说比较简单,功能如下:

    能够设置轮播图的位置大小、设置录播的一组图片用数组实现、是否自动轮播、自动轮播间隔时间。

    使用:

    首先引入ScrollerImage.h 和 ScrollerImage.m文件到工程中

    调用接口:

    -(id)initWithFrame:(CGRect)frame

                  Arrary:(NSArray *)imageArr

            isAutomLunBo:(BOOL)isYes

            setLunBoTime:(NSInteger)intervalTime;

    例如:

    在一个视图控制器中

    #import 'ScrollerImage.h'//引入自定义轮播图

    @property(nonatomic,strong)ScrollerImage * myImageViewScroller;

     //轮播图的图片数组

                    NSArray * arrImg = @[@'1.png',@'2.png',@'3.png',@'4.png',@'5.png',@'6.png',@'7.png',@'8.png',@'9.png'];

                    self.myImageViewScroller = [[ScrollerImage alloc]initWithFrame:view.frame Arrary:arrImg isAutomLunBo:NO setLunBoTime:2.3];

                    [view addSubview:self.myImageViewScroller];

     代码:


    #import <UIKit/UIKit.h>
    
    @interface ScrollerImage : UIView<UIScrollViewDelegate>
    @property(assign)NSInteger count;
    
    -(id)initWithFrame:(CGRect)frame
                  Arrary:(NSArray *)imageArr
            isAutomLunBo:(BOOL)isYes
            setLunBoTime:(NSInteger)intervalTime;
    
    -(void)dealloc;
    @end
     ScrollerImage.h 
    #import 'ScrollerImage.h'
    
    @interface ScrollerImage ()
    
    @property (strong, nonatomic)  UIScrollView *scroll;
    @property (strong, nonatomic)  UILabel *toKonwCurrentPageLabel;
    @property(strong,nonatomic)NSTimer * timer;
    
    @property(assign)int n;
    
    @end
    
    @implementation ScrollerImage
    
    //自定义轮播图
    -(id)initWithFrame:(CGRect)frame Arrary:(NSArray *)imageArr isAutomLunBo:(BOOL)isYes setLunBoTime:(NSInteger)intervalTime;{
        
        if ([super init]) {
            self.frame = frame;
        }
        self.count = imageArr.count;
        CGFloat kWidth = self.frame.size.width;
        CGFloat kHeight = self.frame.size.height;
        //滑块
        self.scroll = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, kWidth, kHeight)];
        self.scroll.contentSize = CGSizeMake(kWidth * imageArr.count, kHeight);
        self.scroll.pagingEnabled = YES;
        self.scroll.delegate = self;
        self.scroll.scrollEnabled = YES;
        [self addSubview:self.scroll];
        //显示图片张数
        self.toKonwCurrentPageLabel = [[UILabel alloc]initWithFrame:CGRectMake(kWidth - 90, kHeight - 30, 60, 20)];
        self.toKonwCurrentPageLabel.layer.masksToBounds = YES;
        self.toKonwCurrentPageLabel.layer.cornerRadius = 11;
        self.toKonwCurrentPageLabel.backgroundColor = [UIColor blackColor];
        self.toKonwCurrentPageLabel.textColor = [UIColor whiteColor];
        self.toKonwCurrentPageLabel.textAlignment = NSTextAlignmentCenter;
        self.toKonwCurrentPageLabel.font = [UIFont systemFontOfSize:12];
        self.toKonwCurrentPageLabel.alpha = 0.3;
        self.toKonwCurrentPageLabel.text = [NSString stringWithFormat:@'1/共%lu张',self.count];
        for (int i = 0; i < imageArr.count; i++) {
            UIImageView * viewImage = [[UIImageView alloc]initWithFrame:CGRectMake(i*kWidth, 0, kWidth, kHeight)];
            viewImage.image = [UIImage imageNamed:imageArr[i]];
            [self.scroll addSubview:viewImage];
        }
        [self.scroll addSubview:self.toKonwCurrentPageLabel];
        [self.scroll bringSubviewToFront:self.toKonwCurrentPageLabel];
        //轮播效果
        if (isYes == YES) {
            self.timer = [NSTimer timerWithTimeInterval:intervalTime target:self selector:@selector(LunBoAction:) userInfo:nil repeats:YES];
            [[NSRunLoop currentRunLoop]addTimer:self.timer forMode:NSRunLoopCommonModes];
        }
        self.n = 0;//初始化轮播位置
        return self;
    }
    
    //LunBo
    -(void)LunBoAction:(NSTimer *)sender{
        self.n +=1;
        self.scroll.contentOffset = CGPointMake(self.scroll.frame.size.width * (self.n % (int)self.count), 0);
        int i = self.n %(int)self.count;
        [self setLabelWith:i contentOffset:self.scroll.frame.size.width andHeight:self.scroll.frame.size.height];
        if (self.n == self.count) {
            self.n = 0;
        }
    }
    //人为滑动图片
    -(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
        CGFloat width = scrollView.frame.size.width;
        CGFloat height = scrollView.frame.size.height;
       self.n  =  scrollView.contentOffset.x/width;
        [self setLabelWith:self.n contentOffset:width andHeight:height];
    }
    -(void)setLabelWith:(int)i contentOffset:(CGFloat)width andHeight:(CGFloat)height{
        self.toKonwCurrentPageLabel.text = [NSString stringWithFormat:@'%d/共%lu张',i+1,self.count];
        self.toKonwCurrentPageLabel.frame = CGRectMake(width*(i + 1) - 90, height - 30 , 60, 20);
    }
    
    -(void)dealloc{
        self.timer = nil;
        [self.timer invalidate];
        
    }
    @end
     ScrollerImage.m

    效果截图:

     

    自定义集合控件的实现

    集合视图也能够实现轮播图,我觉得有时间再次研究轮播图的实现,下面使用到集合视图是解决这类问题,看下面的两幅图片,左边的是在请求数据后解析的结果没有录播图,并且上面四个主题“附近的贴”“精编推荐”。。是不固定的主题,有可能某一天主题变化为两个,下面6个主题的板块主题个数也是有可能变化的。右边的图片中,有轮播图,上下两个板块的功能与图片一中的是一样的。

    技术点分析:

    首先因为主题有可能要变化,根据界面的设计需求,所以最好是使用集合视图UICollectionView 实现。而是否有轮播图可以使用一个布尔值判断,如果有轮播图就开启集合视图的页眉,如果没有就关闭集合视图的页眉,并动态的改变位置。比较难以实现的是,如何在一个 UIViewController 中实现有两个 UICollectionView

    ,对于这个问题,可以在 UICollectionViewDelegate 的协议方法中,根据可重用ID做一下判断即可。 

    有录播图,两个板块主题内容不固定                  

    实现功能的全部源代码:

    需要源代码的园友可以在左侧QQ我哦,如有转载请说明出处,谢谢。


    #import <UIKit/UIKit.h>
    
    @interface ViewController : UIViewController
    
    
    @end
     ViewController.m  
    #import 'ViewController.h'
    #import 'Cell.h'
    #import 'HeaderView.h'
    #import 'FooterView.h'
    #import 'ScrollerImage.h'//引入自定义轮播图
    
    @interface ViewController ()<UICollectionViewDataSource,UICollectionViewDelegate,UICollectionViewDelegateFlowLayout>
    {
        BOOL isHaveLunBo;//判断是否有轮播图
    }
    @property(nonatomic,strong)UIScrollView * scroll;
    @property(nonatomic,strong)ScrollerImage * myImageViewScroller;
    
    @property(nonatomic,strong)UICollectionView * collectionView1;
    @property(nonatomic,strong)UICollectionView * collectionView2;
    
    //测试数据
    @property(nonatomic,strong)NSMutableArray * arrayOfTestDataSouce1;
    @property(nonatomic,strong)NSMutableArray * arrayOfTestDataSouce2;
    
    
    @end
    
    @implementation ViewController
    
    //-lazy
    -(NSMutableArray *)arrayOfTestDataSouce1{
        if (_arrayOfTestDataSouce1 == nil) {
            //我在这里给数据添加数据,可以在请求到数据后再添加数据
            NSArray * testArr = @[@'A',@'B',@'C',@'D'];
            self.arrayOfTestDataSouce1 = [NSMutableArray arrayWithArray:testArr];
            NSLog(@'%@',self.arrayOfTestDataSouce1);
        }
        return _arrayOfTestDataSouce1;
    }
    
    
    -(NSMutableArray *)arrayOfTestDataSouce2{
        if (_arrayOfTestDataSouce2 == nil) {
            //我在这里给数据添加数据,可以在请求到数据后再添加数据
            NSArray * testArr = @[@'AA',@'BB',@'CC',@'DD',@'EE',@'FF'];
            self.arrayOfTestDataSouce2 = [NSMutableArray arrayWithArray:testArr];
            NSLog(@'%@',self.arrayOfTestDataSouce2);
        }
        return _arrayOfTestDataSouce2;
    }
    
    - (void)viewDidLoad {
        [super viewDidLoad];
        
        //关闭毛玻璃效果
        self.navigationController.navigationBar.translucent = NO;
        
        //添加 集合视图1
        UIView * vi = [[UIView alloc] init];
        vi.frame = CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, 125);
        vi.backgroundColor = [UIColor redColor];
        
        UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
        //配置属性
        //1.设置每个item的大小
        layout.itemSize = CGSizeMake(self.view.bounds.size.width / 2 - 10, 50);
        //2.设置缩进量 (上,左,下,右)
        layout.sectionInset = UIEdgeInsetsMake(0, 5, 0, 5);
        //3.设置行的最小间距
        layout.minimumLineSpacing = 2.5;
        //4.设置item的最小间距
        layout.minimumInteritemSpacing = 10;
        
       
        self.collectionView1 = [[UICollectionView alloc] initWithFrame:vi.frame collectionViewLayout:layout];
        //这里巨坑啊,设定代理一定要写到初始化集合视图的下面
        self.collectionView1.delegate = self;
        self.collectionView1.dataSource = self;
        self.collectionView1.backgroundColor = [UIColor brownColor];
    
        [vi addSubview:self.collectionView1];
        [self.view addSubview:vi];
        
        //判断是否有轮播图(默认有-YES)
        isHaveLunBo = YES;
        
        
        //添加 集合视图2
        UICollectionViewFlowLayout *layout2 = [[UICollectionViewFlowLayout alloc] init];
        //配置属性
        //1.设置每个item的大小
        layout2.itemSize = CGSizeMake(50, 50);
        //2.设置缩进量 (上,左,下,右)
        layout2.sectionInset = UIEdgeInsetsMake(0, 5, 0, 5);
        //3.设置行的最小间距
        layout2.minimumLineSpacing = 10;
        //4.设置item的最小间距
        layout2.minimumInteritemSpacing = 10;
        
        
        //设置大小
        if (isHaveLunBo) {
                self.collectionView2 = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 125, self.collectionView1.frame.size.width, 180 + 125) collectionViewLayout:layout2];
        }else{
               self.collectionView2 = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 125, self.collectionView1.frame.size.width, 180) collectionViewLayout:layout2];
        }
    
        self.collectionView2.delegate = self;
        self.collectionView2.dataSource = self;
        [self.view addSubview:self.collectionView2];
        
        
        //注册cell
        [self.collectionView1 registerClass:[Cell class] forCellWithReuseIdentifier:@'item1'];
        [self.collectionView2 registerClass:[Cell class] forCellWithReuseIdentifier:@'item2'];
        
        //注册页眉
        [self.collectionView1 registerClass:[HeaderView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@'header'];
        [self.collectionView2 registerClass:[FooterView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@'footer'];
        //注册页脚
        [self.collectionView2 registerClass:[HeaderView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@'header'];
        [self.collectionView2 registerClass:[FooterView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@'footer'];
        
    }
    
    
    
    #pragma mark - UICollectionViewDataSource -
    //设置分区的item数目
    - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
        if (collectionView == self.collectionView1) {
            return self.arrayOfTestDataSouce1.count;
        }
        else {
            return self.arrayOfTestDataSouce2.count;
        }
     
    }
    
    //设置分区数目
    - (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
    {
        if (collectionView == self.collectionView1) {
            return 1;
        }
        else {
            return 1;
        }
    
    }
    
    #pragma Mark======设置自定义的cell
    - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
      
        if (collectionView == self.collectionView1) {
                  Cell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@'item1' forIndexPath:indexPath];
        cell.lab.text = self.arrayOfTestDataSouce1[indexPath.item];
        cell.lab.frame = cell.bounds;
        
        return cell;
        }
        else {
            Cell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@'item2' forIndexPath:indexPath];
            cell.lab.text = self.arrayOfTestDataSouce2[indexPath.item];
            return cell;
        }
    }
    
    #pragma Mark======设置页眉与页脚的视图
    -(UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath{
        if ([kind isEqualToString:UICollectionElementKindSectionHeader]) {
           
            if (collectionView == self.collectionView2) {
                //返回页眉
                HeaderView * view = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@'header' forIndexPath:indexPath];
                //view.titleLabel.text = @'页眉,可以在黄色区域放轮播图';
                
                if (isHaveLunBo == YES) {
                    //轮播图的图片数组
                    NSArray * arrImg = @[@'1.png',@'2.png',@'3.png',@'4.png',@'5.png',@'6.png',@'7.png',@'8.png',@'9.png'];
                    self.myImageViewScroller = [[ScrollerImage alloc]initWithFrame:view.frame Arrary:arrImg isAutomLunBo:NO setLunBoTime:2.3];
                    [view addSubview:self.myImageViewScroller];
                    return view;
                }else{
                    return nil;
                }
            }else{
                return nil;
            }
            
        } else {
            //返回页脚
    //        FooterView *footer = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@'footer' forIndexPath:indexPath];
    //        footer.footerLabel.text = @'页脚';
    //        return footer;
            return nil;
        }
    
    }
    
    
    #pragma mark - UICollectionViewDelegateFlowLayout -
    //动态配置每个分区的item的size大小
    - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
        if (indexPath.section == 0) {
            return CGSizeMake((self.view.frame.size.width - 15)/2, 50);
        }
        return CGSizeMake((self.view.frame.size.width - 60)/3, 50);
    }
    //动态配置item的缩进量
    - (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
        if (section == 0) {
            //上、左、下、右
            return UIEdgeInsetsMake(10, 5, 10, 5);
        }
        return UIEdgeInsetsMake(10, 5, 10, 5);
    }
    //动态配置item 左右最小间距
    - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
        return 5;
    }
    //动态配置行的最小间距
    - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
        return 5;
    }
    //动态的设置页眉
    -(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section{
        
        if (collectionView == self.collectionView1) {
            //这里也可以仿照下面写法,为 collectionView1 设定是否添加页眉
            return CGSizeMake(0, 0);
        }else{
            if (isHaveLunBo) {
                return CGSizeMake(20, 100);
            }else{
                return CGSizeMake(0, 0);
            }
           
        }
        
    }
    
    //动态的设置页脚
    -(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section{
        return CGSizeMake(0, 0);
    }
    
    #pragma mark - UICollectionViewDelegate -
    - (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    //选中某一行的点击事件写这里
        NSLog(@'选择了');
    }
    
    - (void)didReceiveMemoryWarning {
        [super didReceiveMemoryWarning];
        // Dispose of any resources that can be recreated.
    }
    
    @end
     ViewController.m  
    #import <UIKit/UIKit.h>
    
    @interface ScrollerImage : UIView<UIScrollViewDelegate>
    @property(assign)NSInteger count;
    
    -(id)initWithFrame:(CGRect)frame
                  Arrary:(NSArray *)imageArr
            isAutomLunBo:(BOOL)isYes
            setLunBoTime:(NSInteger)intervalTime;
    
    -(void)dealloc;
    @end
     ScrollerImage.h 
    #import 'ScrollerImage.h'
    
    @interface ScrollerImage ()
    
    @property (strong, nonatomic)  UIScrollView *scroll;
    @property (strong, nonatomic)  UILabel *toKonwCurrentPageLabel;
    @property(strong,nonatomic)NSTimer * timer;
    
    @property(assign)int n;
    
    @end
    
    @implementation ScrollerImage
    
    //自定义轮播图
    -(id)initWithFrame:(CGRect)frame Arrary:(NSArray *)imageArr isAutomLunBo:(BOOL)isYes setLunBoTime:(NSInteger)intervalTime;{
        
        if ([super init]) {
            self.frame = frame;
        }
        self.count = imageArr.count;
        CGFloat kWidth = self.frame.size.width;
        CGFloat kHeight = self.frame.size.height;
        //滑块
        self.scroll = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, kWidth, kHeight)];
        self.scroll.contentSize = CGSizeMake(kWidth * imageArr.count, kHeight);
        self.scroll.pagingEnabled = YES;
        self.scroll.delegate = self;
        self.scroll.scrollEnabled = YES;
        [self addSubview:self.scroll];
        //显示图片张数
        self.toKonwCurrentPageLabel = [[UILabel alloc]initWithFrame:CGRectMake(kWidth - 90, kHeight - 30, 60, 20)];
        self.toKonwCurrentPageLabel.layer.masksToBounds = YES;
        self.toKonwCurrentPageLabel.layer.cornerRadius = 11;
        self.toKonwCurrentPageLabel.backgroundColor = [UIColor blackColor];
        self.toKonwCurrentPageLabel.textColor = [UIColor whiteColor];
        self.toKonwCurrentPageLabel.textAlignment = NSTextAlignmentCenter;
        self.toKonwCurrentPageLabel.font = [UIFont systemFontOfSize:12];
        self.toKonwCurrentPageLabel.alpha = 0.3;
        self.toKonwCurrentPageLabel.text = [NSString stringWithFormat:@'1/共%lu张',self.count];
        for (int i = 0; i < imageArr.count; i++) {
            UIImageView * viewImage = [[UIImageView alloc]initWithFrame:CGRectMake(i*kWidth, 0, kWidth, kHeight)];
            viewImage.image = [UIImage imageNamed:imageArr[i]];
            [self.scroll addSubview:viewImage];
        }
        [self.scroll addSubview:self.toKonwCurrentPageLabel];
        [self.scroll bringSubviewToFront:self.toKonwCurrentPageLabel];
        //轮播效果
        if (isYes == YES) {
            self.timer = [NSTimer timerWithTimeInterval:intervalTime target:self selector:@selector(LunBoAction:) userInfo:nil repeats:YES];
            [[NSRunLoop currentRunLoop]addTimer:self.timer forMode:NSRunLoopCommonModes];
        }
        self.n = 0;//初始化轮播位置
        return self;
    }
    
    //LunBo
    -(void)LunBoAction:(NSTimer *)sender{
        self.n +=1;
        self.scroll.contentOffset = CGPointMake(self.scroll.frame.size.width * (self.n % (int)self.count), 0);
        int i = self.n %(int)self.count;
        [self setLabelWith:i contentOffset:self.scroll.frame.size.width andHeight:self.scroll.frame.size.height];
        if (self.n == self.count) {
            self.n = 0;
        }
    }
    //人为滑动图片
    -(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
        CGFloat width = scrollView.frame.size.width;
        CGFloat height = scrollView.frame.size.height;
       self.n  =  scrollView.contentOffset.x/width;
        [self setLabelWith:self.n contentOffset:width andHeight:height];
    }
    -(void)setLabelWith:(int)i contentOffset:(CGFloat)width andHeight:(CGFloat)height{
        self.toKonwCurrentPageLabel.text = [NSString stringWithFormat:@'%d/共%lu张',i+1,self.count];
        self.toKonwCurrentPageLabel.frame = CGRectMake(width*(i + 1) - 90, height - 30 , 60, 20);
    }
    
    -(void)dealloc{
        self.timer = nil;
        [self.timer invalidate];
        
    }
    @end
     ScrollerImage.m
    #import <UIKit/UIKit.h>
    
    @interface FooterView : UICollectionReusableView
    @property (nonatomic, retain) UILabel *footerLabel;
    
    @end
     FooterView.h 
    #import 'FooterView.h'
    
    @implementation FooterView
    - (instancetype)initWithFrame:(CGRect)frame {
        self = [super initWithFrame:frame];
        if (self) {
            [self addSubview:self.footerLabel];
        }
        return self;
    }
    
    - (UILabel *)footerLabel {
        if (!_footerLabel) {
            self.footerLabel = [[UILabel alloc] initWithFrame:self.bounds];
            _footerLabel.backgroundColor = [UIColor greenColor];
        }
        return _footerLabel;
    }
    
    @end
     FooterView.m
    #import <UIKit/UIKit.h>
    
    
    @interface HeaderView : UICollectionReusableView
    @property (nonatomic, retain) UILabel *titleLabel;
    
    @end
     HeaderView.h
    #import 'HeaderView.h'
    
    @implementation HeaderView
    
    
    - (instancetype)initWithFrame:(CGRect)frame {
        self = [super initWithFrame:frame];
        if (self) {
            [self addSubview:self.titleLabel];
        }
        return self;
    }
    
    - (UILabel *)titleLabel {
        if (!_titleLabel) {
            self.titleLabel = [[UILabel alloc] initWithFrame:self.bounds];
            _titleLabel.backgroundColor = [UIColor yellowColor];
        }
        return _titleLabel;
    }
    
    @end
     HeaderView.m
    #import <UIKit/UIKit.h>
    
    @interface Cell : UICollectionViewCell
    
    @property(nonatomic,strong)UILabel * lab;
    
    @end
     Cell.h 
    #import 'Cell.h'
    
    @implementation Cell
    
    - (instancetype)initWithFrame:(CGRect)frame {
        self = [super initWithFrame:frame];
        if (self) {
            //按照此格式,添加一些其他控件
            [self.contentView addSubview:self.lab];
        }
        return self;
    }
    
    
    - (UILabel *)lab {
        if (!_lab) {
            self.lab = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
            //测试颜色
            _lab.backgroundColor = [UIColor greenColor];
            
            _lab.textAlignment = NSTextAlignmentCenter;
            _lab.font = [UIFont systemFontOfSize:15];
        }
        return _lab;
    }
    
    @end
     Cell.m

    源代码实现效果:

    左边图片假设没有请求到轮播图,右边图片假设请求到轮播图,关键代码

    isHaveLunBo = YES;如果为NO,不显示录播图,具体情况根据网络请求结果处理,这里仅仅模拟效果。

                      

     

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