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// |
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// UINavigationBarBackButtonHandler.swift |
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// Demo |
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// |
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// Created by HamGuy on 20/04/2017. |
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// Copyright © 2017 hamguy.net. All rights reserved. |
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// |
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import Foundation |
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/// Handle UINavigationBar's 'Back' button action |
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protocol UINavigationBarBackButtonHandler { |
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/// Should block the 'Back' button action |
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/// |
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/// - Returns: true - dot block，false - block |
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func shouldPopOnBackButton() -> Bool |
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} |
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extension UIViewController: UINavigationBarBackButtonHandler { |
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//Do not block the "Back" button action by default, otherwise, override this function in the specified viewcontroller |
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func shouldPopOnBackButton() -> Bool { |
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return true |
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} |
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} |
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extension UINavigationController: UINavigationBarDelegate { |
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public func navigationBar(_ navigationBar: UINavigationBar, shouldPop item: UINavigationItem) -> Bool{ |
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guard let items = navigationBar.items else { |
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return false |
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} |
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if viewControllers.count < items.count { |
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return true |
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} |
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var shouldPop = true |
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if let vc = topViewController, vc.responds(to: #selector(UIViewController.shouldPopOnBackButton)){ |
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shouldPop = vc.shouldPopOnBackButton() |
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} |
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if shouldPop{ |
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DispatchQueue.main.async { |
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self.popViewController(animated: true) |
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} |
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}else{ |
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for aView in navigationBar.subviews{ |
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if aView.alpha > 0 && aView.alpha < 1{ |
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aView.alpha = 1.0 |
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} |
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} |
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} |
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return false |
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} |
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} |
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/// Use age |
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class SomeController: UIViewController{ |
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/** |
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...... |
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do something |
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*/ |
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override func shouldPopOnBackButton() -> Bool { |
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/** |
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do something |
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return false/true |
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*/ |
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} |
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// Handle the pop gesture |
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override func willMove(toParentViewController parent: UIViewController?) { |
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if parent == nil { // When the user swipe to back, the parent is nil |
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do something |
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return |
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} |
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super.willMove(toParentViewController: parent) |
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} |
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} |
not working ...