iOS 关于使用xib创建cell的两种初始化方式

第一步：
[self.collectionView registerNib:[UINib nibWithNibName:@"QGLShareBtnCell" bundle:nil] forCellWithReuseIdentifier:@"QGLShareBtnCell”];
第二步：
QGLShareBtnCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"QGLShareBtnCell" forIndexPath:indexPath];

QGLIMGroupListCell *cell = (QGLIMGroupListCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell= (QGLIMGroupListCell *)[[[NSBundle  mainBundle]  loadNibNamed:@"QGLIMGroupListCell" owner:self options:nil]  lastObject];
}