按下UINavigationController的后退按钮时执行操作 [英] Execute action when back bar button of UINavigationController is pressed

问题描述

当按下 UINavigationController 的后退按钮时，我需要执行一个动作（清空数组），而按钮仍然会导致前一个 ViewController 出现在堆栈上。我怎么能用swift完成这个？

I need to execute an action (emptying an array), when the back button of a UINavigationController is pressed, while the button still causes the previous ViewController on the stack to appear. How could I accomplish this using swift?

推荐答案

一个选项是实现自己的自定义后退按钮。您需要将以下代码添加到viewDidLoad方法：

One option would be implementing your own custom back button. You would need to add the following code to your viewDidLoad method:

- (void) viewDidLoad {
    [super viewDidLoad];
    self.navigationItem.hidesBackButton = YES;
    UIBarButtonItem *newBackButton = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStyleBordered target:self action:@selector(back:)];
    self.navigationItem.leftBarButtonItem = newBackButton;
}

- (void) back:(UIBarButtonItem *)sender {
    // Perform your custom actions
    // ...
    // Go back to the previous ViewController
    [self.navigationController popViewControllerAnimated:YES];
}

更新：

以下是Swift的版本：

Here is the version for Swift:

    override func viewDidLoad {
        super.viewDidLoad()
        self.navigationItem.hidesBackButton = true
        let newBackButton = UIBarButtonItem(title: "Back", style: UIBarButtonItemStyle.Bordered, target: self, action: "back:")
        self.navigationItem.leftBarButtonItem = newBackButton
    }

    func back(sender: UIBarButtonItem) {
        // Perform your custom actions
        // ...
        // Go back to the previous ViewController
        self.navigationController?.popViewControllerAnimated(true)
    }

更新2：

以下是Swift 3的版本：

Here is the version for Swift 3:

    override func viewDidLoad {
        super.viewDidLoad()
        self.navigationItem.hidesBackButton = true
        let newBackButton = UIBarButtonItem(title: "Back", style: UIBarButtonItemStyle.plain, target: self, action: #selector(YourViewController.back(sender:)))
        self.navigationItem.leftBarButtonItem = newBackButton
    }

    func back(sender: UIBarButtonItem) {
        // Perform your custom actions
        // ...
        // Go back to the previous ViewController
        _ = navigationController?.popViewController(animated: true)
    }

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