我如何在UICollectionView的一个部分设置单元格间距?我知道有一个属性minimumInteritemSpacing,我已经将它设置为5.0,但间距仍然没有出现5.0。我已经实现了flowout委托方法。
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section
{
return 5.0;
}
我仍然没有得到想要的结果。我认为这是最小间距。有没有什么方法可以设置最大间距?
投票的答案(以及快速版本)有一个小问题:右边会有一个很大的空格。
这是因为流布局是定制的,以使单元格间距精确,具有浮动左行为。
我的解决方案是操纵部分插入,使部分是对齐中心,但间距是完全指定的。
在下面的截图中,项目/行间距正好是8pt,而左右插入部分将大于8pt(使其居中对齐):
这样的Swift代码:
private let minItemSpacing: CGFloat = 8
private let itemWidth: CGFloat = 100
private let headerHeight: CGFloat = 32
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// Create our custom flow layout that evenly space out the items, and have them in the center
let layout = UICollectionViewFlowLayout()
layout.itemSize = CGSize(width: itemWidth, height: itemWidth)
layout.minimumInteritemSpacing = minItemSpacing
layout.minimumLineSpacing = minItemSpacing
layout.headerReferenceSize = CGSize(width: 0, height: headerHeight)
// Find n, where n is the number of item that can fit into the collection view
var n: CGFloat = 1
let containerWidth = collectionView.bounds.width
while true {
let nextN = n + 1
let totalWidth = (nextN*itemWidth) + (nextN-1)*minItemSpacing
if totalWidth > containerWidth {
break
} else {
n = nextN
}
}
// Calculate the section inset for left and right.
// Setting this section inset will manipulate the items such that they will all be aligned horizontally center.
let inset = max(minItemSpacing, floor( (containerWidth - (n*itemWidth) - (n-1)*minItemSpacing) / 2 ) )
layout.sectionInset = UIEdgeInsets(top: minItemSpacing, left: inset, bottom: minItemSpacing, right: inset)
collectionView.collectionViewLayout = layout
}
上面vojtech-vrbka的解决方案是正确的,但它会触发一个警告:
警告:UICollectionViewFlowLayout缓存的帧不匹配索引路径-缓存值:这可能是因为流布局子类layout是修改UICollectionViewFlowLayout返回的属性而没有复制它们
下面的代码应该修复它:
class CustomViewFlowLayout : UICollectionViewFlowLayout {
let cellSpacing:CGFloat = 4
override func layoutAttributesForElementsInRect(rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
let original = super.layoutAttributesForElementsInRect(rect)
if let original = original {
let attributes = NSArray.init(array: original, copyItems: true) as! [UICollectionViewLayoutAttributes]
for (index, attribute) in attributes.enumerate() {
if index == 0 { continue }
let prevLayoutAttributes = attributes[index - 1]
let origin = CGRectGetMaxX(prevLayoutAttributes.frame)
if(origin + cellSpacing + attribute.frame.size.width < self.collectionViewContentSize().width) {
attribute.frame.origin.x = origin + cellSpacing
}
}
return attributes
}
return nil
}
}
试试下面的代码,确保每个项目之间的间距为5px:
- (UIEdgeInsets)collectionView:(UICollectionView *) collectionView
layout:(UICollectionViewLayout *) collectionViewLayout
insetForSectionAtIndex:(NSInteger) section {
return UIEdgeInsetsMake(0, 0, 0, 5); // top, left, bottom, right
}
- (CGFloat)collectionView:(UICollectionView *) collectionView
layout:(UICollectionViewLayout *) collectionViewLayout
minimumInteritemSpacingForSectionAtIndex:(NSInteger) section {
return 5.0;
}
我在Swift 3单元格间距的解决方案,如Instagram:
lazy var collectionView: UICollectionView = {
let layout = UICollectionViewFlowLayout()
let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
cv.backgroundColor = UIColor.rgb(red: 227, green: 227, blue: 227)
cv.showsVerticalScrollIndicator = false
layout.scrollDirection = .vertical
layout.minimumLineSpacing = 1
layout.minimumInteritemSpacing = 1
return cv
}()
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
switch UIDevice.current.modelName {
case "iPhone 4":
return CGSize(width: 106, height: 106)
case "iPhone 5":
return CGSize(width: 106, height: 106)
case "iPhone 6,7":
return CGSize(width: 124, height: 124)
case "iPhone Plus":
return CGSize(width: 137, height: 137)
default:
return CGSize(width: frame.width / 3, height: frame.width / 3)
}
}
如何编程检测设备:
https://stackoverflow.com/a/26962452/6013170