Swift 重构：通过预设视图样式，缩减代码量

通过预设常用视图基础属性，缩减每次创建时需要声明的属性行数（之后创建时不需要再重复声明），项目越大收益越高；

🌰🌰：

{

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {


    UIApplication.setupAppearance(.white, barTintColor: .systemBlue)

}

源码：

@objc public extension UIApplication{


    /// 配置 app 外观主题色

    static func setupAppearance(_ tintColor: UIColor, barTintColor: UIColor) {

        _ = {

            $0.barTintColor = barTintColor

            $0.tintColor = tintColor

            $0.titleTextAttributes = [NSAttributedString.Key.foregroundColor: tintColor,]

          }(UINavigationBar.appearance())



        _ = {

            $0.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.black], for: .normal)

          }(UIBarButtonItem.appearance(whenContainedInInstancesOf: [UIImagePickerController.self]))



        _ = {

            $0.setTitleColor(tintColor, for: .normal)

            $0.titleLabel?.adjustsFontSizeToFitWidth = true;

            $0.titleLabel?.minimumScaleFactor = 1.0;

            $0.imageView?.contentMode = .scaleAspectFit

            $0.isExclusiveTouch = true

            $0.adjustsImageWhenHighlighted = false

          }(UIButton.appearance(whenContainedInInstancesOf: [UINavigationBar.self]))



        _ = {

            $0.tintColor = tintColor


            $0.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: tintColor,

            ], for: .normal)

            $0.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: barTintColor,

            ], for: .selected)

          }(UISegmentedControl.appearance(whenContainedInInstancesOf: [UINavigationBar.self]))



        _ = {

            $0.tintColor = tintColor

          }(UISegmentedControl.appearance())



        _ = {

            $0.autoresizingMask = [.flexibleWidth, .flexibleHeight]

            $0.showsHorizontalScrollIndicator = false

            $0.keyboardDismissMode = .onDrag;

            if #available(iOS 11.0, *) {

                $0.contentInsetAdjustmentBehavior = .never;

            }

          }(UIScrollView.appearance())



        _ = {

            $0.separatorInset = .zero

            $0.separatorStyle = .singleLine

            $0.rowHeight = 60

            $0.backgroundColor = .groupTableViewBackground

            if #available(iOS 11.0, *) {

                $0.estimatedRowHeight = 0.0;

                $0.estimatedSectionHeaderHeight = 0.0;

                $0.estimatedSectionFooterHeight = 0.0;

            }

          }(UITableView.appearance())



        _ = {

            $0.layoutMargins = .zero

            $0.separatorInset = .zero

            $0.selectionStyle = .none

            $0.backgroundColor = .white

          }(UITableViewCell.appearance())



        _ = {

            $0.scrollsToTop = false

            $0.isPagingEnabled = true

            $0.bounces = false

          }(UICollectionView.appearance())



        _ = {

            $0.layoutMargins = .zero

            $0.backgroundColor = .white

          }(UICollectionViewCell.appearance())



        _ = {

            $0.titleLabel?.adjustsFontSizeToFitWidth = true;

            $0.titleLabel?.minimumScaleFactor = 1.0;

            $0.imageView?.contentMode = .scaleAspectFit

            $0.isExclusiveTouch = true

            $0.adjustsImageWhenHighlighted = false

          }(UIButton.appearance())



        _ = {

            $0.isUserInteractionEnabled = true;

          }(UIImageView.appearance())



        _ = {

            $0.isUserInteractionEnabled = true;

          }(UILabel.appearance())



        _ = {

            $0.pageIndicatorTintColor = barTintColor

            $0.currentPageIndicatorTintColor = tintColor

            $0.isUserInteractionEnabled = true;

            $0.hidesForSinglePage = true;

          }(UIPageControl.appearance())



        _ = {

            $0.progressTintColor = barTintColor

            $0.trackTintColor = .clear

          }(UIProgressView.appearance())



        _ = {

            $0.datePickerMode = .date;

            $0.locale = Locale(identifier: "zh_CN");

            $0.backgroundColor = .white;

            if #available(iOS 13.4, *) {

                $0.preferredDatePickerStyle = .wheels

            }

          }(UIDatePicker.appearance())



        _ = {

            $0.minimumTrackTintColor = tintColor

            $0.autoresizingMask = .flexibleWidth

          }(UISlider.appearance())



        _ = {

            $0.onTintColor = tintColor

            $0.autoresizingMask = .flexibleWidth

          }(UISwitch.appearance())


    }

}