在iOS 11 以下可以通过添加space的方式实现，但是iOS 11 之后引入了safe area这个方式仍然受限于safe area。 iOS 11以后需要调整layoutMargins值。
注意因为是运行时 swizzleMethod 交换方法实现，所以引入将会使得整个工程生效，可能影响三方库，例如 ImagePicker
本文通过区分版本，遍历navview调整相应的视图，且使用swizzleMethod无痕注入
封装: 使用了swizzleMethod在多个地方无痕设置
参考代码如下：
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#### 唯一需要注意的地方就是在iOS 11以下使用”hideRightNavigationBar“需要hideButtons，原因上边已经写出了
import Foundation
import UIKit
extension NSObject {
static func swizzleMethod(_ cls: AnyClass, originalSelector: Selector, swizzleSelector: Selector){
let originalMethod = class_getInstanceMethod(cls, originalSelector)!
let swizzledMethod = class_getInstanceMethod(cls, swizzleSelector)!
let didAddMethod = class_addMethod(cls,
originalSelector,
method_getImplementation(swizzledMethod),
method_getTypeEncoding(swizzledMethod))
if didAddMethod {
class_replaceMethod(cls,
swizzleSelector,
method_getImplementation(originalMethod),
method_getTypeEncoding(originalMethod))
} else {
method_exchangeImplementations(originalMethod,
swizzledMethod)
}
}
}
extension UIApplication {
private static let classSwizzedMethod: Void = {
UINavigationController.sx_initialize
if #available(iOS 11.0, *) {
UINavigationBar.sx_initialize
}
}()
open override var next: UIResponder? {
UIApplication.classSwizzedMethod
return super.next
}
}
//swiftlint:disable identifier_name
public var sx_defultFixSpace: CGFloat = 0
public var sx_disableFixSpace: Bool = false
extension UINavigationController {
private struct AssociatedKeys {
static var tempDisableFixSpace = "tempDisableFixSpace"
static var tempBehavor = "tempBehavor"
}
static let sx_initialize: Void = {
DispatchQueue.once(UUID().uuidString) {
swizzleMethod(UINavigationController.self,
originalSelector: #selector(UINavigationController.viewDidLoad),
swizzleSelector: #selector(UINavigationController.sx_viewDidLoad))
swizzleMethod(UINavigationController.self,
originalSelector: #selector(UINavigationController.viewWillAppear(_:)),
swizzleSelector: #selector(UINavigationController.sx_viewWillAppear(_:)))
swizzleMethod(UINavigationController.self,
originalSelector: #selector(UINavigationController.viewWillDisappear(_:)),
swizzleSelector: #selector(UINavigationController.sx_viewWillDisappear(_:)))
}
}()
private var tempDisableFixSpace: Bool {
get {
return objc_getAssociatedObject(self, &AssociatedKeys.tempDisableFixSpace) as? Bool ?? false
}
set {
objc_setAssociatedObject(self, &AssociatedKeys.tempDisableFixSpace, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
@available(iOS 11.0, *)
private var tempBehavor: UIScrollViewContentInsetAdjustmentBehavior {
get {
return objc_getAssociatedObject(self, &AssociatedKeys.tempBehavor) as? UIScrollViewContentInsetAdjustmentBehavior ?? .automatic
}
set {
objc_setAssociatedObject(self, &AssociatedKeys.tempBehavor, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
@objc private func sx_viewDidLoad() {
disableFixSpace(true, with: true)
sx_viewDidLoad()
}
@objc private func sx_viewWillAppear(_ animated: Bool) {
disableFixSpace(true, with: false)
sx_viewWillAppear(animated)
}
@objc private func sx_viewWillDisappear(_ animated: Bool) {
disableFixSpace(false, with: true)
sx_viewWillDisappear(animated)
}
private func disableFixSpace(_ disable: Bool, with temp: Bool) {
if type(of: self) == UIImagePickerController.self {
if disable == true {
if temp { tempDisableFixSpace = sx_disableFixSpace }
sx_disableFixSpace = true
if #available(iOS 11.0, *) {
tempBehavor = UIScrollView.appearance().contentInsetAdjustmentBehavior
UIScrollView.appearance().contentInsetAdjustmentBehavior = .automatic
}
} else {
sx_disableFixSpace = tempDisableFixSpace
if #available(iOS 11.0, *) {
UIScrollView.appearance().contentInsetAdjustmentBehavior = tempBehavor
}
}
}
}
}
@available(iOS 11.0, *)
extension UINavigationBar {
static let sx_initialize: Void = {
DispatchQueue.once(UUID().uuidString) {
swizzleMethod(UINavigationBar.self,
originalSelector: #selector(UINavigationBar.layoutSubviews),
swizzleSelector: #selector(UINavigationBar.sx_layoutSubviews))
}
}()
@objc func sx_layoutSubviews() {
sx_layoutSubviews()
if sx_disableFixSpace == false {
layoutMargins = .zero
let space = sx_defultFixSpace
for view in subviews {
if NSStringFromClass(view.classForCoder).contains("ContentView") {
view.layoutMargins = UIEdgeInsetsMake(0, space, 0, space)
}
}
}
}
}
extension UINavigationItem {
private enum BarButtonItem: String {
case left = "_leftBarButtonItem"
case right = "_rightBarButtonItem"
}
open override func setValue(_ value: Any?, forKey key: String) {
if #available(iOS 11.0, *) {
super.setValue(value, forKey: key)
} else {
if sx_disableFixSpace == false && (key == BarButtonItem.left.rawValue || key == BarButtonItem.right.rawValue) {
guard let item = value as? UIBarButtonItem else {
super.setValue(value, forKey: key)
return
}
let space = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)
space.width = sx_defultFixSpace - 16
if key == BarButtonItem.left.rawValue {
leftBarButtonItems = [space, item]
} else {
rightBarButtonItems = [space, item]
}
} else {
super.setValue(value, forKey: key)
}
}
}
}
extension DispatchQueue {
static var `default`: DispatchQueue { return DispatchQueue.global(qos: .`default`) }
static var userInteractive: DispatchQueue { return DispatchQueue.global(qos: .userInteractive) }
static var userInitiated: DispatchQueue { return DispatchQueue.global(qos: .userInitiated) }
static var utility: DispatchQueue { return DispatchQueue.global(qos: .utility) }
static var background: DispatchQueue { return DispatchQueue.global(qos: .background) }
func after(_ delay: TimeInterval, execute closure: @escaping () -> Void) {
asyncAfter(deadline: .now() + delay, execute: closure)
}
private static var _onceTracker = [String]()
public class func once(_ token: String, block:()->Void) {
objc_sync_enter(self)
defer { objc_sync_exit(self) }
if _onceTracker.contains(token) {
return
}
_onceTracker.append(token)
block()
}
}
