.m

#import "LNCustomCollectionView.h"

// 单元格
@interface HomeMenuCell : UICollectionViewCell

// 图片
@property (strong, nonatomic) UIImageView *imageView;
// 文本
@property (strong, nonatomic) UILabel *label;

@end

// 视图
@interface HomeMenuCollectionView : LNCustomCollectionView

@end


#import "HomeMenuCollectionView.h"

// 单元格
@implementation HomeMenuCell

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        // 图片
        UIImageView *imageView = [UIImageView new];
        imageView.layer.masksToBounds = YES;
        imageView.contentMode = UIViewContentModeScaleAspectFill;
        [self.contentView addSubview:imageView];
        [imageView mas_makeConstraints:^(MASConstraintMaker *make) {
            make.width.height.equalTo(@59);
            make.top.offset(15);
            make.centerX.offset(0);
        }];
        self.imageView = imageView;
        
        // 文本
        UILabel *label = [UILabel new];
        label.font = [UIFont boldSystemFontOfSize:14];
        label.textColor = HEXCOLOR(0x333333);
        label.textAlignment = NSTextAlignmentCenter;
        [self.contentView addSubview:label];
        [label mas_makeConstraints:^(MASConstraintMaker *make) {
            make.top.equalTo(imageView.mas_bottom).offset(0);
            make.left.right.offset(0);
        }];
        self.label = label;
    }
    return self;
}

@end

// 视图
@implementation HomeMenuCollectionView

- (void)commonInit {
    [super commonInit];
    
    UICollectionViewFlowLayout *layout = (UICollectionViewFlowLayout *)self.collectionViewLayout;
    layout.sectionInset = UIEdgeInsetsMake(0, 0, 0, 0);
    layout.minimumInteritemSpacing = 0;
    layout.minimumLineSpacing = 0;

    [self registerClass:[HomeMenuCell class] forCellWithReuseIdentifier:@"HomeMenuCell"];
}

- (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    HomeMenuCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"HomeMenuCell" forIndexPath:indexPath];
    id item = self.itemArray[indexPath.row];
    if (self.bind) {
        self.bind(item, cell);
    }
    return cell;
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    const NSInteger kItemNumOfRow = 4;
    UICollectionViewFlowLayout *layout = (UICollectionViewFlowLayout *)self.collectionViewLayout;
    NSInteger row = indexPath.row;
    CGFloat totalWidth = self.frame.size.width - layout.sectionInset.left - layout.sectionInset.right - layout.minimumInteritemSpacing * (kItemNumOfRow - 1);
    CGFloat width;
    
    if (row % kItemNumOfRow) {
        width = roundf(totalWidth / kItemNumOfRow);
    } else {
        width = totalWidth - roundf(totalWidth / kItemNumOfRow) * (kItemNumOfRow - 1);
    }
    
    return CGSizeMake(width, 100);
}

@end