如果你想在不影响实际单元格大小的情况下调整间距，这是最适合我的解决方案。#xcode 9 #tvOS11 #iOS11 #swift

在uicollectionviewdelegatflowlayout中，改变实现下一个方法，诀窍是你必须使用它们两个，文档并没有真正指向我去思考那个方向。: D

open func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    return cellSpacing
}

public func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return cellSpacing
}

记住，它是最小行间距，而不是最小项间距或单元格间距。因为你的collectionView的滚动方向是水平的。

如果是垂直的，则需要为单元格之间的水平空间设置单元格空间或项间空间，为单元格之间的垂直空间设置行间距。

objective - c版本

- (CGFloat)collectionView:(UICollectionView *)collectionView
                       layout:(UICollectionViewLayout*)collectionViewLayout
    minimumLineSpacingForSectionAtIndex:(NSInteger)section
    {
        return 20;
    }

斯威夫特版本:

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return 20
}

支持第一个问题。我试图在UICollectionView上获得5px的间距，但这并不奏效，以及UIEdgeInsetsMake(0,0,0,0)…

在UITableView中，我可以通过直接指定一行中的x,y坐标来做到这一点。

这是我的UICollectionView代码:

#pragma mark collection view cell layout / size
- (CGSize)collectionView:(UICollectionView*)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    return [self getCellSize:indexPath];  // will be w120xh100 or w190x100
    // if the width is higher, only one image will be shown in a line
}

#pragma mark collection view cell paddings
- (UIEdgeInsets)collectionView:(UICollectionView*)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
    return UIEdgeInsetsMake(0, 0, 0, 0); // top, left, bottom, right
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {

    return 5.0;
}

更新:用下面的代码解决了我的问题。

ViewController。m

#import "ViewController.h"
#import "MagazineCell.h" // created just the default class. 

static NSString * const cellID = @"cellID";

@interface ViewController ()

@end

@implementation ViewController

#pragma mark - Collection view
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return 30;
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    MagazineCell *mCell = (MagazineCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellID forIndexPath:indexPath];

    mCell.backgroundColor = [UIColor lightGrayColor];

    return mCell;
}

#pragma mark Collection view layout things
// Layout: Set cell size
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {

    NSLog(@"SETTING SIZE FOR ITEM AT INDEX %d", indexPath.row);
    CGSize mElementSize = CGSizeMake(104, 104);
    return mElementSize;
}
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
    return 2.0;
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
    return 2.0;
}

// Layout: Set Edges
- (UIEdgeInsets)collectionView:
(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
   // return UIEdgeInsetsMake(0,8,0,8);  // top, left, bottom, right
    return UIEdgeInsetsMake(0,0,0,0);  // top, left, bottom, right
}

@end

使用水平流布局，我也得到了10点之间的单元格间距。为了移除间距，我需要将minimumlinespespaces和minimumInterItemSpacing设置为零。

UICollectionViewFlowLayout *flow = [[UICollectionViewFlowLayout alloc] init];
flow.itemSize = CGSizeMake(cellWidth, cellHeight);
flow.scrollDirection = UICollectionViewScrollDirectionHorizontal;
flow.minimumInteritemSpacing = 0;
flow.minimumLineSpacing = 0;

此外，如果所有单元格大小相同，直接在流布局上设置属性比使用委托方法更简单、更有效。

以前的版本并没有真正工作的部分> 1。所以我的解决方案在这里找到了https://codentrick.com/create-a-tag-flow-layout-with-uicollectionview/。对于懒惰的人:

override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
    let attributesForElementsInRect = super.layoutAttributesForElements(in: rect)
    var newAttributesForElementsInRect = [UICollectionViewLayoutAttributes]()
    // use a value to keep track of left margin
    var leftMargin: CGFloat = 0.0;
    for attributes in attributesForElementsInRect! {
        let refAttributes = attributes 
        // assign value if next row
        if (refAttributes.frame.origin.x == self.sectionInset.left) {
            leftMargin = self.sectionInset.left
        } else {
            // set x position of attributes to current margin
            var newLeftAlignedFrame = refAttributes.frame
            newLeftAlignedFrame.origin.x = leftMargin
            refAttributes.frame = newLeftAlignedFrame
        }
        // calculate new value for current margin
        leftMargin += refAttributes.frame.size.width + 10
        newAttributesForElementsInRect.append(refAttributes)
    }

    return newAttributesForElementsInRect
}

Swift 3版本

简单地创建一个UICollectionViewFlowLayout子类并粘贴这个方法。

override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
        guard let answer = super.layoutAttributesForElements(in: rect) else { return nil }

        for i in 1..<answer.count {
            let currentAttributes = answer[i]
            let previousAttributes = answer[i - 1]

            let maximumSpacing: CGFloat = 8
            let origin = previousAttributes.frame.maxX

            if (origin + maximumSpacing + currentAttributes.frame.size.width < self.collectionViewContentSize.width && currentAttributes.frame.origin.x > previousAttributes.frame.origin.x) {
                var frame = currentAttributes.frame
                frame.origin.x = origin + maximumSpacing
                currentAttributes.frame = frame
            }
        }

        return answer
}