解决collectionview的reloaddata闪一下问题

方式一:

[UIView setAnimationsEnabled:NO];
[collectionView performBatchUpdates:^{
    [collectionView reloadData];
} completion:^(BOOL finished) {
    [UIView setAnimationsEnabled:YES];
}];

方式二:

[UIView animateWithDuration:0 animations:^{
    [collectionView performBatchUpdates:^{
        [collectionView reloadData];
    } completion:nil];
}];