iOS中UICollectionView自适应

1、效果图：

2、配置collection

- (UICollectionView *)collectionView {

    if (!_collectionView) {

        UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc]init];

  layout.estimatedItemSize = UICollectionViewFlowLayoutAutomaticSize;// 自适应

        if([layoutrespondsToSelector:@selector(_setRowAlignmentsOptions:)]) {// cell的对齐方式

            [layoutperformSelector:@selector(_setRowAlignmentsOptions:)withObject:@{@"UIFlowLayoutCommonRowHorizontalAlignmentKey":@(NSTextAlignmentLeft)}];

        }

        _collectionView = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:layout];

    }

    return _collectionView;

}

3、获取collectionView的总高度

self.collectionView.collectionViewLayout.collectionViewContentSize.height;

4、关于cell，不要在layoutsubViews里适配，直接在init适配

  [self.titleLabel mas_makeConstraints:^(MASConstraintMaker *make) {

            make.edges.equalTo(self.contentView).insets(UIEdgeInsetsMake(10, 12, 10, 12));

        }];