1.利用謂語語法和正則表達式，判斷字符串是否符合特定格式

//利用謂語語法悔捶，判斷一個字符串是否是郵箱峻黍。
func isValidEmail(testStr: String) -> Bool {
    //可以根據(jù)自己的需要改成別的正則表達式
    let emailRegex = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}"
    let emailTest = NSPredicate(format: "SELF MATCHES %@", emailRegex)
    return emailTest.evaluate(with: testStr)
}
isValidEmail(testStr: "213@12.com")//true

2.如何判斷app運行在真機還是模擬器上面

#if (arch(i386) || arch(x86_64)) && os(iOS)
    //如果是模擬器流昏，則會運行精盅，真機上面則不會執(zhí)行
    print("模擬器")
#endif
    print("正常代碼")

3.OC中的 | 在，swift中如何使用

//oc中溯祸，|的使用，如下所示
let view = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 568))
addSubview(view)
view.autoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight
//而在swift中舞肆，應該這樣使用
view.autoresizingMask = [.flexibleWidth, .flexibleHeight]

4.用什么方法實現(xiàn)OC的respondsToSelector方法

//使用如下方式代替
if let delegate = delegate {//判斷是否存在代理
    if let theMethod = delegate.theOptionalProtocolMethod? {//判斷代理是否實現(xiàn)方法
        theMethod()
        return
    }
}

5.如何將路徑等轉換編碼方式

let originalString = "test/test"
//.urlHostAllowed可以換成需要的轉換類型
var escapedString = originalString.addingPercentEncoding(withAllowedCharacters: .urlHostAllowed)
print(escapedString)//Optional("test%2Ftest")

6.如何快速的獲得某個date的年月日時分秒等

let date = Date()
//獲得當天的日歷對象
let calendar = Calendar.current
//獲得小時
let hour = calendar.component(.hour, from: date)
//獲得分鐘
let minutes = calendar.component(.minute, from: date)

7.如何給UITextView添加placeholder占位符

//定義了一個全局的常量
let placeholderText = "請輸入內(nèi)容焦辅！"
//1.給textview擴展如下方法：
extension UITextView {
    func addPlaceholderText(text: String) {
        self.text = text
        self.textColor = .lightGray
    }
}
//2.創(chuàng)建出textview
        textView = UITextView(frame: view.frame)
        textView.delegate = self
        textView.addPlaceholderText(text: placeholderText)
        view.addSubview(textView)
//3.在textview的下列代理方法中，實現(xiàn)如下兩個方法椿胯，添加如下代碼
    func textViewDidBeginEditing(_ textView: UITextView) {
        if textView.textColor == .lightGray {
            textView.text = nil
            textView.textColor = .black
        }
    }
    
    func textViewDidEndEditing(_ textView: UITextView) {
        if textView.text.isEmpty {
            textView.addPlaceholderText(text: placeholderText)
        }
    }

只需要以上操作筷登，textview就可以跟textfield一樣，擁有一個placeholder占位符提示語

8.格式化輸出Int

三種方式

//方法一：
let str = String(format: "%02d-%03d", 1,2)//01-002

//方法二
let str2 = String(format: "%02d-%03d", arguments: [1,2])//01-002

//方法三
let formatter = NumberFormatter()
formatter.minimumIntegerDigits = 2
let str3 = formatter.string(from: 1)//01

9.獲得字典的key數(shù)組

let dict = ["a":1,"b":2]
let keys = Array(dict.keys)
keys.map { print($0) }//打印key

//如果是nsdictionary哩盲，使用alleys即可
let keys = dict.allKeys

10.搜索指定的文件夾路勁

let documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]

11.獲得app設置中version版本號

比如在設置中前方，我們設置的如圖：

屏幕快照 2017-05-08 下午2.56.42.png

let verson = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as! String
print(version)//1.0.1

12.設置tableview的分割線separator的顏色，寬度等

        tableView.separatorColor = .red//分割線顏色
        tableView.separatorStyle = .singleLineEtched//分割線樣式
//        tableView.separatorEffect//效果
        tableView.separatorInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)//分割線內(nèi)邊距廉油，都設置為0惠险，則會出現(xiàn)一條寬等于屏幕的完整的分割線

13.如何安全的使用array，如果下標越界等情況發(fā)生時抒线，不會崩潰

//給collection擴展一個下標方法
extension Collection where Indices.Iterator.Element == Index {
    subscript (safe index: Index) -> Generator.Element? {
        return indices.contains(index) ? self[index] : nil
    }
}
//使用
let arr = [1]
arr[safe: 2]//nil莺匠，會得到一個nil，而不會崩潰

14.如何使用iOS自帶的tableview刷新控件

//創(chuàng)建出刷新控件
        let refreshControl = UIRefreshControl()
        refreshControl.attributedTitle = NSAttributedString(string: "開始刷新")
        refreshControl.addTarget(self, action: #selector(refresh(sender:)), for: .valueChanged)
        //添加上去即可
        tableView.addSubview(refreshControl)

//實現(xiàn)刷新函數(shù)
    func refresh(sender: AnyObject) {
        //做刷新要做的事情
        print("開始刷新")
    }
        
        //結束刷新十兢，需要結束的時候調(diào)用
        refreshControl.endRefreshing()

15.如何快速實現(xiàn)趣竣，鍵盤彈起，view跟著上移旱物，鍵盤消失遥缕，恢復原位

//添加一個監(jiān)聽，監(jiān)聽鍵盤的彈起
   NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil);
//監(jiān)聽鍵盤的消失
   NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil);
//上移頁面
func keyboardWillShow(sender: NSNotification) {
     self.view.frame.origin.y = -150 // Move view 150 points upward 
}
//恢復
func keyboardWillHide(sender: NSNotification) {
     self.view.frame.origin.y = 0 // Move view to original position  
}

16.如何獲得一個view的快照宵呛，并生成image

extension UIView {
    func takeSnapshot() -> UIImage {
        UIGraphicsBeginImageContextWithOptions(bounds.size, false, UIScreen.main.scale)
        drawHierarchy(in: self.bounds, afterScreenUpdates: true)
        let image = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()
        return image
    }
}

17.如何設置導航條背景单匣、字體顏色，tabbar背景宝穗、字體顏色

//Navigation Bar:
navigationController?.navigationBar.barTintColor = UIColor.green
//Navigation Bar Text:
navigationController?.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.orange]
//Tab Bar:
tabBarController?.tabBar.barTintColor = UIColor.brown
//Tab Bar Text:
tabBarController?.tabBar.tintColor = UIColor.yellow

18.如何刪除array已知元素

//擴展一個方法
extension Array where Element: Equatable {
    //刪除匹配到的第一個元素
    mutating func remove(object: Element) {
        if let index = index(of: object) {
            remove(at: index)
        }
    }
}

19.快速比較户秤，兩個date之間的差距，比如相差多少年月日等

extension Date {
    //返回相差多少年
    func years(from date: Date) -> Int {
        return Calendar.current.dateComponents([.year], from: date, to: self).year ?? 0
    }
    //返回差多少月
    func months(from date: Date) -> Int {
        return Calendar.current.dateComponents([.month], from: date, to: self).month ?? 0
    }
    //返回差多少周
    func weeks(from date: Date) -> Int {
        return Calendar.current.dateComponents([.weekOfMonth], from: date, to: self).weekOfMonth ?? 0
    }
    //返回差多少天
    func days(from date: Date) -> Int {
        return Calendar.current.dateComponents([.day], from: date, to: self).day ?? 0
    }
    //返回差多少小時
    func hours(from date: Date) -> Int {
        return Calendar.current.dateComponents([.hour], from: date, to: self).hour ?? 0
    }
    //返回差多少分鐘
    func minutes(from date: Date) -> Int {
        return Calendar.current.dateComponents([.minute], from: date, to: self).minute ?? 0
    }
    //返回差多少秒
    func seconds(from date: Date) -> Int {
        return Calendar.current.dateComponents([.second], from: date, to: self).second ?? 0
    }
    //返回差距的描述
    func offset(from date: Date) -> String {
        if years(from: date)   > 0 { return "\(years(from: date))y"   }
        if months(from: date)  > 0 { return "\(months(from: date))M"  }
        if weeks(from: date)   > 0 { return "\(weeks(from: date))w"   }
        if days(from: date)    > 0 { return "\(days(from: date))d"    }
        if hours(from: date)   > 0 { return "\(hours(from: date))h"   }
        if minutes(from: date) > 0 { return "\(minutes(from: date))m" }
        if seconds(from: date) > 0 { return "\(seconds(from: date))s" }
        return ""
    }
}
//使用
let date1 = DateComponents(calendar: .current, year: 2014, month: 11, day: 28, hour: 5, minute: 9).date!
let date2 = DateComponents(calendar: .current, year: 2015, month: 8, day: 28, hour: 5, minute: 9).date!

let years = date2.years(from: date1)     // 0
let months = date2.months(from: date1)   // 9
let weeks = date2.weeks(from: date1)     // 39
let days = date2.days(from: date1)       // 273
let hours = date2.hours(from: date1)     // 6,553
let minutes = date2.minutes(from: date1) // 393,180
let seconds = date2.seconds(from: date1) // 23,590,800

let timeOffset = date2.offset(from: date1) // "9M"

let date3 = DateComponents(calendar: .current, year: 2014, month: 11, day: 28, hour: 5, minute: 9).date!
let date4 = DateComponents(calendar: .current, year: 2015, month: 11, day: 28, hour: 5, minute: 9).date!

let timeOffset2 = date4.offset(from: date3) // "1y"

let date5 = DateComponents(calendar: .current, year: 2017, month: 4, day: 28).date!
let now = Date()
let timeOffset3 = now.offset(from: date5) // "1w"

//或者使用date components formatter
let dateComponentsFormatter = DateComponentsFormatter()
dateComponentsFormatter.allowedUnits = [.year,.month,.weekOfYear,.day,.hour,.minute,.second]
dateComponentsFormatter.maximumUnitCount = 1
dateComponentsFormatter.unitsStyle = .full
dateComponentsFormatter.string(from: Date(), to: Date(timeIntervalSinceNow: 4000000))  // "1 month"