Swift
对象数据转字典
通讯录中UITableView的数据源.
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| let arr = [ContactsModel]
let res = Dictionary(grouping: arr, by: { $0.name.prefix(1).uppercased()})
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汉字转拼音
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| extension String {
func transformToPinYin() -> String {
let mutableString = NSMutableString(string: self)
CFStringTransform(mutableString, nil, kCFStringTransformToLatin, false)
CFStringTransform(mutableString, nil, kCFStringTransformStripDiacritics, false)
let string = String(mutableString)
return string.replacingOccurrences(of: " ", with: "")
}
}
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Hex to byte
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| extension StringProtocol {
var hexa2Bytes: [UInt8] {
let hexa = Array(self)
return stride(from: 0, to: count, by: 2).compactMap { UInt8(String(hexa[$0..<$0.advanced(by: 2)]), radix: 16) }
}}
}
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获取UICollectionView显示的中间的Cell
遵守Scrollview的代理方法
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| func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
let centerCellIndexPath = dateCollectView!.getMidVisibleIndexPath()
let horDateSelectorCollectionViewCell = dateCollectView!.cellForItem(at: centerCellIndexPath!) as? FDHorDateSelectorCollectionViewCell
}
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对UICollectionViewCell的extension
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| protocol CollectionVisibleMidCell {}
extension CollectionVisibleMidCell where Self: UICollectionView {
func getMidVisibleIndexPath() -> IndexPath? {
var visibleRect = CGRect()
visibleRect.origin = self.contentOffset
visibleRect.size = self.bounds.size
let visiblePoint = CGPoint(x: visibleRect.midX, y: visibleRect.midY)
guard let indexPath = self.indexPathForItem(at: visiblePoint) else { return nil }
return indexPath
}
}
extension UICollectionView: CollectionVisibleMidCell {}
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UITableView无刷新动画的刷新
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DispatchQueue.main.async {
UIView.performWithoutAnimation {
self.tableView.reloadData()
}
}
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在合适的的时机移除通知和定时器
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| @available(iOS 5.0, *)
open var isMovingFromParent: Bool { get }
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在viewWillDisappear判断当前VC是由Pop,调用的，还是由Push调用的，可以再合适的时机调用移除通知或定时器。
swift的forin循环遍历
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var items = ["Swift", "OC", "Javascript"]
for _ in items {
items.removeLast()
}
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swift中的循环遍历删除不会崩溃的。(官方源码)原因是在它的迭代器进行循环的，上面的代码可转化成如下代码
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| var items = ["Swift", "OC", "Javascript"]
var itemsIterator = items.makeIterator()
while let item = itemsIterator.next() {
items.removeLast()
}
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用Label显示Unicode
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let label = UILabel.init(frame: CGRect.init(x: 10, y: 86, width: 100, height: 100))
label.text = "\u{1F32D}"
self.view.addSubview(label)
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在String通过下标获取字符
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| private extension String {
subscript (index: Int) -> Character {
return self[self.index(self.startIndex, offsetBy: index)]
}
}
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OC
