防止uicollectionview单元格窗体在有空间时向右移动SWIFT

Question

我的问题是，当下一个单元格跳到第二行并且第一行中存在空格时，uicollectionview单元格正在向左移动（空格不适合包含下一个单元格），如何防止单元格移动到右侧，即使仍有空间时，我还需要像单元格之间的setMaximumSpace（它不存在）之类的东西？

这里是我的代码：

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell { 
    let cell = mycollectionView.dequeueReusableCellWithReuseIdentifier("CharakterCell", forIndexPath: indexPath) as CharakterCollectionViewCell 

    for (var i=0 ; i<4 ; i++) 
    { 
     if (collectionCellIndex[i] == nil) 
     { 
      collectionCellIndex[i] = indexPath 
      println("\(collectionCellIndex[i])") 
      println(i) 
      break 
     } 
    } 

    return cell 
} 


func collectionView(collectionView: UICollectionView, layout collectionViewLayout:UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize { 
    var size = CGSize(width: 0, height: 0) 
    var label = UILabel() 
    if (selectedCharInCollectionNames[indexPath.row] == "") 
    { 
     size = CGSize(width: 40, height: 30) 

    } 
    else 
    { 
     label.text = selectedCharInCollectionNames[indexPath.row] 
     label.sizeToFit() 
     var width = label.frame.width 
     size = CGSize(width: (width+25), height: 30) 

    } 
    label.sizeToFit() 
    return size 
} 

private let sectionInsets = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10) 

func collectionView(collectionView: UICollectionView!, 
    layout collectionViewLayout: UICollectionViewLayout!, 
    insetForSectionAtIndex section: Int) -> UIEdgeInsets { 


     return sectionInsets 
} 

Answer 1

@Kevin阅读答题here！解决了我的问题

class AlignLeftFlowLayout: UICollectionViewFlowLayout { 

var maximumCellSpacing = CGFloat(9.0) 

override func layoutAttributesForElementsInRect(rect: CGRect) -> [AnyObject]? { 
    let attributesToReturn = super.layoutAttributesForElementsInRect(rect) as? [UICollectionViewLayoutAttributes] 

    for attributes in attributesToReturn ?? [] { 
     if attributes.representedElementKind == nil { 
      attributes.frame = self.layoutAttributesForItemAtIndexPath(attributes.indexPath).frame 
     } 
    } 

    return attributesToReturn 
} 

override func layoutAttributesForItemAtIndexPath(indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes! { 
    let curAttributes = super.layoutAttributesForItemAtIndexPath(indexPath) 
    let sectionInset = (self.collectionView?.collectionViewLayout as UICollectionViewFlowLayout).sectionInset 

    if indexPath.item == 0 { 
     let f = curAttributes.frame 
     curAttributes.frame = CGRectMake(sectionInset.left, f.origin.y, f.size.width, f.size.height) 
     return curAttributes 
    } 

    let prevIndexPath = NSIndexPath(forItem: indexPath.item-1, inSection: indexPath.section) 
    let prevFrame = self.layoutAttributesForItemAtIndexPath(prevIndexPath).frame 
    let prevFrameRightPoint = prevFrame.origin.x + prevFrame.size.width + maximumCellSpacing 

    let curFrame = curAttributes.frame 
    let stretchedCurFrame = CGRectMake(0, curFrame.origin.y, self.collectionView!.frame.size.width, curFrame.size.height) 

    if CGRectIntersectsRect(prevFrame, stretchedCurFrame) { 
     curAttributes.frame = CGRectMake(prevFrameRightPoint, curFrame.origin.y, curFrame.size.width, curFrame.size.height) 
    } else { 
     curAttributes.frame = CGRectMake(sectionInset.left, curFrame.origin.y, curFrame.size.width, curFrame.size.height) 
    } 

    return curAttributes 
} 

}