UICollectionView的橫向滾動，目前我使用在了顯示輸入框的輸入歷史上；

//
//  SCVisitorInputAccessoryView.m
//  訪客通行錄入頁面--訪客姓名輸入歷史的InputAccessory

#import "SCInputAccessoryView.h"
#import "SCInputAccessoryCell.h"

#define SCHorizontalMargin   15.0f
#define SCVerticalMargin     10.0f

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

@property (weak, nonatomic) IBOutlet UICollectionView *collectionView;

/// 名字記錄的陣列
@property (nonatomic, strong) NSMutableArray *nameArray;

@end


@implementation SCInputAccessoryView

+ (instancetype)loadNibView {
    return [[[NSBundle
 
 mainBundle] loadNibNamed:[SCInputAccessoryView className] owner:self options:nil] objectAtIndex:0];
}

- (void)awakeFromNib {
    [super awakeFromNib];
    self.clipsToBounds = YES;
    self.collectionView.delegate = self;
    self.collectionView.dataSource = self;
    [self setupView];
}

- (void)setupView {

    /// 設定此屬性為yes 不滿一螢幕 也能滾動
 

    self.collectionView.alwaysBounceHorizontal = YES;
    self.collectionView.showsHorizontalScrollIndicator = NO;
    // 1.建立流水佈局
    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
    layout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
    self.collectionView.collectionViewLayout = layout;
    [self registerNibWithTableView];
}

#pragma mark - 代理方法 Delegate Methods
// 設定分割槽

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
    return 1;
}

// 每個分割槽上得元素個數
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return self.nameArray.count;
}

// 設定cell
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {

    SCInputAccessoryCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:NSStringFromClass([SCInputAccessoryCell class]) forIndexPath:indexPath];
    [cell refreshCellWithTitle:self.nameArray[indexPath.row]];
    return cell;
}

// 設定cell大小 itemSize：可以給每一個cell指定不同的尺寸
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    CGFloat height = 35.0f;
    CGFloat width = [self gainStringWidthWithString:self.nameArray[indexPath.row] font:15.0f height:height];
    return CGSizeMake(width, height);
}


// 設定UIcollectionView整體的內邊距（這樣item不貼邊顯示）
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
    // 上 左 下 右
    return UIEdgeInsetsMake(SCVerticalMargin, SCHorizontalMargin, SCVerticalMargin, SCHorizontalMargin);
}

// 設定minimumLineSpacing：cell上下之間最小的距離
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
    return SCHorizontalMargin;
}

// 設定minimumInteritemSpacing：cell左右之間最小的距離
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
    return SCHorizontalMargin;
}

// 選中cell的回撥
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    if (self.selectRowBlock) {
        self.selectRowBlock(indexPath.row, self.nameArray[indexPath.row]);
    }
}

#pragma mark - 對外方法 Public Methods
/// array數組裡面放的元素 必須字串型別的
- (void)refreshUIWithNameArray:(NSArray<NSString *> *)array  {
    [self.nameArray removeAllObjects];
    [self.nameArray addObjectsFromArray:array];
    [self.collectionView reloadData];
}


#pragma mark - 內部方法 Private Methods
// 註冊cell
- (void)registerNibWithTableView {
    [self.collectionView registerNib:[UINib nibWithNibName:[SCInputAccessoryCell className] bundle:nil] forCellWithReuseIdentifier:NSStringFromClass([SCInputAccessoryCell class])];
}

- (CGFloat)gainStringWidthWithString:(NSString *)string font:(CGFloat)font height:(CGFloat)height {

    if (string.length == 0) {
        return 0.0f;
    }

    CGSize maxSize = CGSizeMake(MAXFLOAT, height);
    CGSize realSize = [string boundingRectWithSize:maxSize
                                           options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
                                        attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:font]}
                                           context:nil].size;
    /// 左右各16
    return (realSize.width + 2 * (SCHorizontalMargin + 1.f));
}

#pragma mark - 點選/觸碰事件 Action Methods

#pragma mark - 懶載入 Lazy Load

- (NSMutableArray *)nameArray {
    if (!_nameArray) {
        _nameArray = [NSMutableArray arrayWithCapacity:0];
    }
    return _nameArray;
}

@end

效果圖：