下拉(解決設(shè)置contentInset 遮擋mj_header顯示關(guān)鍵代碼)
MJRefreshNormalHeader *header = [MJRefreshNormalHeader headerWithRefreshingBlock:^{
[self requestForData];
}];
header.ignoredScrollViewContentInsetTop = 30.f;
self.collectionView.mj_header = header;