在我的应用程序中创建自定义后退按钮答案

【问题标题】：Creating a custom back button across my app在我的应用程序中创建自定义后退按钮
【发布时间】：2018-01-15 10:12:47
【问题描述】：

我正在尝试更改应用程序中导航控制器后退按钮的默认外观。

我想使用 and image(icon) 并删除“Back”文本。这段代码在按钮上拉伸了图像，并没有删除按钮标题。

let backImg: UIImage = UIImage(named: "icon_back")!
UIBarButtonItem.appearance().setBackButtonBackgroundImage(backImg, for: .normal, barMetrics: .default)

一个建议是在AppDelegate里面怎么做(didFinishLaunchingWithOptions)？

【问题讨论】：

用它创建一个 UIViewController 的基础子类。
@ElTomato 你能解释一下吗？感谢您的帮助。

标签： ios swift uinavigationcontroller uibarbuttonitem

【解决方案1】：

最简单的方法是为您的项目创建一个BaseViewController，它派生自UIViewController。您可以使用BaseViewController 中的常用方法在每个视图控制器中创建您的custom leftBarButton。你项目中剩下的viewController应该是derived from this BaseViewController，

class BaseViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        createLeftBarButton(image: #Pass image here#, width: #Pass width of your image view#) // Create custom back bar button.
    }

    /**Create cutom back bar button*/
    func createLeftBarButton(image: UIImage?, width: CGFloat) {

        let backButton: UIButton = UIButton(frame: CGRect(x: 0, y: 0, width: width, height: 50))
        backButton.imageView?.contentMode = .scaleAspectFill
        backButton.imageView?.bounds = CGRect(x: 0, y: 0, width: width, height: width)
        backButton.setImage(image, for: .normal)
        backButton.setImage(image, for: .highlighted)
        backButton.addTarget(self, action: #selector(leftBarButtonItemPressed(_:)), for: .touchUpInside)

        let leftItem: UIBarButtonItem = UIBarButtonItem(customView: backButton)
        navigationItem.leftBarButtonItem = leftItem

    }

    /**Custom back bar button pressed. So handle here*/
    func leftBarButtonItemPressed(_ sender: UIButton) {

        view.endEditing(true) // End editing if any.
        if isViewControllerPresented() { // Check view controller is presented or pushed
            dismiss(animated: true, completion: nil) // Dismiss ViewController if presented
        } else {
            _ = navigationController?.popViewController(animated: true) // Pop ViewController if pushed
        }

    }

    /**To check whether view controller is presented or pushed.*/
    func isViewControllerPresented() -> Bool {

        if self.presentingViewController?.presentedViewController == self {
            return true
        }
        if (self.navigationController != nil && self.navigationController?.presentingViewController?.presentedViewController == self.navigationController) && self.navigationController?.viewControllers.count == 1 {
            return true
        }
        if self.tabBarController?.presentingViewController is UITabBarController {
            return true
        }
        return false

    }

  }

// Sub class your remaining viewControllers like this.
class FirstViewController: BaseViewController {

    override func viewDidLoad() {
        super.viewDidLoad() // When calling this super method, the custom back bar button will be created for you
    }

}

谢谢。

【讨论】：

【解决方案2】：

你可以通过设置navigationItem的BackButtonBackgroundImage来做到这一点；

你也可以设置全局效果的外观：

let item = UIBarButtonItem.appearance(whenContainedInInstancesOf: [UINavigationBar.self]) item.setBackButtonBackgroundVerticalPositionAdjustment(-10, for: .default) item.setBackButtonBackgroundImage(youImage, for: .normal, barMetrics: .default)

要删除后面的标题，你可以这样做：

@implementation UINavigationItem (BackItem)

-(UIBarButtonItem *)backBarButtonItem { UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithTitle:@" " style:UIBarButtonItemStylePlain target:nil action:nil]; item.tintColor = [UIColor darkGrayColor]; return item; }

@end

【讨论】：