collectionView切换 layout

效果图(真机效果好一点.毕竟 gif)

collectionViewChange.gif

切换 layout 方法

- (void)changeLayout{
    _isSortByDay = !_isSortByDay;
    if (firstLayout) {
         [self.collectionView reloadData];
         [self.collectionView setCollectionViewLayout:_threeLayout animated:YES];
    }else{
         [self.collectionView reloadData];
         [self.collectionView setCollectionViewLayout:_fourLayout animated:YES];  
    }
}

layout

@interface 哼 ()
// 每行个数
@property (nonatomic,assign)NSInteger numberOfLine;
@property (nonatomic,assign)CGFloat margin;
@end


@implementation嗯哼
- (instancetype)initWithNumberOfLine:(NSInteger)num andAllMargin:(CGFloat)margin{
    self = [super init];
    if (self) {
        self.numberOfLine = num;
        self.margin = margin;
    }
    return self;
}
- (void)prepareLayout{
    [super prepareLayout];
    
    // num + 1 为间距
    CGFloat wh = (self.collectionView.size.width - self.margin * (self.numberOfLine + 1)) / self.numberOfLine;
    
    self.itemSize = CGSizeMake(wh, wh);
    self.minimumInteritemSpacing = _margin;
    self.minimumLineSpacing = _margin;
    self.scrollDirection = UICollectionViewScrollDirectionVertical;
    self.sectionInset = UIEdgeInsetsMake(0, _margin, 0, _margin);
    self.collectionView.showsHorizontalScrollIndicator = NO;
    self.collectionView.showsVerticalScrollIndicator = NO;
}