Swift Code Block Backups

简单粗暴 不定期更新（始于161128）......

1. 打开关闭闪光灯

 let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
 if device.hasTorch {
        do {
             try device.lockForConfiguration()
        } catch _ {
        }
       device.torchMode = AVCaptureTorchMode.On // .Off
       device.unlockForConfiguration()
 }

2. UISearchBar 去除背景灰色

let searchBar = UISearchBar.init(frame: CGRect(x: 10, y: 5, width: ScreenWidth-70, height: 30))
for subview in searchBar.subviews {
     if subview.isKind(of: NSClassFromString("UIView")!) && subview.subviews.count > 0 {
          subview.subviews.first!.removeFromSuperview()
     }
  }

3. 某一页隐藏 navigationbar，下一页显示

 override func viewWillAppear(_ animated: Bool) {
      super.viewWillAppear(animated)
      navigationController?.setNavigationBarHidden(true, animated: true)
 }

 override func viewWillDisappear(_ animated: Bool) {
      super.viewWillDisappear(animated)
      navigationController?.setNavigationBarHidden(false, animated: true)
 }

4. delegate

 protocol NewHomeTopSearchViewDelegate: NSObjectProtocol {
       func topViewBeginSearch()
 }

 class NewHomeTopSearchView: UIView, UISearchBarDelegate {
      var delegate: NewHomeTopSearchViewDelegate?
    
      func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
          if let delegate = delegate {
              delegate.topViewBeginSearch()
          }
       }
 }

5. SnapKit 是 Masonry 的 Swift 版本，资源地址：Masonry，SnapKit
   基本用法如下：

myPointLabel.snp.makeConstraints { (make) 
       make.top.equalTo(signButton.snp.top).offset(20)
       make.height.equalTo(signButton)
       make.left.equalToSuperview()
       make.right.equalTo(signButton.snp.left).offset(-10)
 }

6. button 整体位置

button.contentHorizontalAlignment = UIControlContentHorizontalAlignment.left
button.contentVerticalAlignment = UIControlContentVerticalAlignment.top

7. 类方法

class func newHomeGetItemHeight(ratioWidth: CGFloat, ratioHegiht: CGFloat, width: CGFloat) -> CGFloat {
        return width * ratioHegiht / ratioWidth
    }

8. 碰到了一个约束的问题：依据 屏幕w 动态适应了 itemH，但是由于 item 中 仅仅按照比例设置了 imgView的宽高，又由于 按比例计算了itemH，那么在不同的尺寸下（SE），imgView 与 item 动态的改变了 H，但是其他的控件的高度没变，所以其他控件就不正常的显示了 ---> 解决：如果需要按照比例设置item，那么应该给 item中的 每个控件 都添加比例约束
   xib中 单个控件 按比例设置宽高约束：xib中固定好相对位置（比如 设置好上左右约束后 手动设置正确的高度，然是不要把高度加入约束中，而是图8-0） -> 按比例设置好宽高，但不要添加到约束中 - 图8-0

图8-0

图8-1

图8-2

9. appdelegate 获取 storyboard 创建的 UITabBarController

let tabbarVC = self.window?.rootViewController as! UITabBarController
tabbarVC.tabBar.tintColor = UIColor.init(rgb: 0xFF2832)

10. 修改状态栏的背景色

extension UIApplication {
      var statusBarView: UIView? {
          return value(forKey: "statusBar") as? UIView
      }
}  
UIApplication.shared.statusBarView?.backgroundColor = .red

11. 当 vc 在 nvc 中的时候，需要更改状态栏颜色

// 状态栏字体为白色，状态栏和导航栏背景为黑色 
self.navigationController?.navigationBar.barStyle = .black
// 状态栏字体为黑色，状态栏和导航栏背景为白色
self.navigationController?.navigationBar.barStyle = .default

12. 获取文字的宽高

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()

        let text = name_label.text! as NSString

        let length = text.boundingRect(with: CGSize.init(width: CGFloat.greatestFiniteMagnitude, height: 15), options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName : name_label.font], context: nil).size.width + 1

        name_label.snp.remakeConstraints { (make) in
            make.top.equalTo(41)
            make.width.equalTo(length)
            make.height.equalTo(15)
            make.left.equalTo(avatarImgView.snp.right).offset(25)
        }

    }

13. 获取空间最大y

signature_label.frame.maxY

14. 初始化一个存放 label 的数组

private var label_array = Array()

15. 获取当前日期为星期几

        var calendar = NSCalendar.current

        calendar.timeZone = TimeZone.init(identifier: "Asia/Shanghai")!

        let components = calendar.component(.weekday, from: Date.init())

        print(components)

16. 判断点击区域

    override func touchesEnded(_ touches: Set, with event: UIEvent?) {
        let touch = (touches as NSSet).anyObject() as! UITouch

        let point = touch.location(in: self.view)

        if !self.collectionView.frame.contains(point) {

            self.navigationController?.popViewController(animated: true)
        }
    }

17. 某一个vc 隐藏 statusbar

override var prefersStatusBarHidden: Bool {

        return true
    }

18. 转 str 并保留两位小数

String.init(format: "%.2f", doublevalue)

19. UIKeyboardWillChangeFrame

 NotificationCenter.default.addObserver(self, selector: #selector(keybordChanged), name: .UIKeyboardWillChangeFrame, object: nil)

20. 图片拉伸

private lazy var bgImgView: UIImageView = {
        var image = UIImage.init(named: "r_beijing")
        image = image?.stretchableImage(withLeftCapWidth: Int((image?.size.width)!/2.0), topCapHeight: Int((image?.size.height)!/2.0))

        let imgView = UIImageView.init()
        imgView.image = image
        imgView.isUserInteractionEnabled = true
        return imgView
    } ()

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