ios - 如何在方向更改时重新计算UICollectionViewFlowLayout？

Question

纵向显示，我所有的CollectionViewCells都正确对齐。



当切换到横向时，单元格现在间隔更大。



在方向更改时重新计算UICollectionViewFlowLayout's minimumInterimSpacing和itemSize的正确方法是什么？我想在横向显示6列。

Answer 1

使用此逻辑可根据您的设备方向更改单元格的大小和间距。

-(void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator{
    //create two properties for storing a bool and sizeOfYourScreen
    //In your viewDidLoad method initialize both of these object with NO and self.view.frame.size
    //get your Portrait screen size
    if (portraitScreenSize > size.height) {
        self.isPortrate = NO;
    }else{
        self.isPortrate = YES;
    }
    self.size = size;
    [self.collectionView reloadData];
}
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section
{
    if (self.isPortrate) {

        //Calculate your interitemSpacing with respect to size and then simply return it
        return newInteritemSpacing;
    }else{
        //Calculate your interitemSpacing with respect to size and then simply return it
        return newInteritemSpacing;
    }

}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
{
    if (self.isPortrate) {

        //Calculate your lineSpacing with respect to size and then simply return it
        return newlineSpacing;
    }else{
        //Calculate your interitemSpacing with respect to size and then simply return it
        return newlineSpacing;
    }
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    //Here you should return your size of each item
    if (self.isPortrate) {

        //Calculate your lineSpacing with respect to size and then simply return it
        return sizeOfCellInPortrate;
    }else{
        //Calculate your interitemSpacing with respect to size and then simply return it
        return sizeOfCellInLandscape;
    }
}