解决UICollectionView ReloadData闪一下

参考: https://www.cnblogs.com/Rinpe/p/5850238.html

1. 在更新期间关闭动画

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

2.将更新动画时间设置为0 (已验证)

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