导航项按钮未显示 [英] navigationItem button not showing

问题描述

我有一个 UINavigationItem 我想显示一个 UIBarButtonItem.

I have a UINavigationItem i am trying to show a UIBarButtonItem.

现在的问题是我正确添加了它们，它们可以正常工作并且 100% 工作.

Now the problem is i added them correctly, they're functional and working 100%.

但它们没有显示在 UINavigationBar 上.

but they're not showing on the UINavigationBar.

现在对于流程，我正在执行以下操作.

Now for the flow I am doing the following.

1- 我隐藏了后退按钮，就像这样

1- I am hiding the back button, like this

self.navigationItem.setHidesBackButton(isBackHidden, animated: false)

2- 当用户点击 UIButton 时，我在运行时动态地使用函数添加这 2 个按钮.

2- I am adding those 2 buttons using a function dynamically at run time, when a user tap on a UIButton.

let rightBarItem = UIBarButtonItem(title: "Button.Done".localized, style: .plain, target: self, action: #selector(self.saveButtonTapped))
navigationItem.rightBarButtonItem = rightBarItem     
let leftBarItem = UIBarButtonItem(title: "Button.Cancel".localized, style: .plain, target: self, action: #selector(self.cancelButtonTapped))
navigationItem.rightBarButtonItem?.tintColor = .red // still nothing    
navigationItem.leftBarButtonItem = leftBarItem

3- 我尝试使用这些函数，但结果仍然相同

3- I have tried to use those functions and still the same result

self.navigationItem.setLeftBarButton(UIBarButtonItem?, animated: Bool)
self.navigationItem.setRightBarButton(UIBarButtonItem?, animated: Bool)

总结:

我尝试更改 tintColor，因为它们在功能上正常工作，我认为这是颜色问题.

I have tried to change the tintColor as they're functionally working i thought it was a color problem.

我尝试在 DispatchQueue.main.async {} 中使用它们，认为这可能是一个线程问题，因为它是动态的.

I have tried to use them inside DispatchQueue.main.async {} thinking it might be a thread problem since it dynamic.

我已经调试并检查了 UINavigationItem 中的项目并且它们存在.

I have debugged and check for the items in the UINavigationItem and they're exist.

主要发生了什么:

按钮没有显示，但在 UINavigationItem 上点击它们的位置时它们工作得很好.

The buttons are not shown but they are working just fine when tapped on their places on the UINavigationItem.

推荐答案

现在的问题是我正确添加了它们，它们可以正常工作并且工作 100%.

Now the problem is i added them correctly, they're functional and working 100%.

但它们没有显示在 UINavigationBar 上.

but they're not showing on the UINavigationBar.

根据您提到的内容，这只是一个 UI 问题 - 原因不明.

Based on what you mentioned, it is just a UI issue -for unknown reason-.

因此，您可以做的是确认导航项中将显示按钮项，即让栏按钮项具有自定义视图.添加 UIButton 作为 UIBarButtonItem 的自定义视图将是有效的，如下所示:

So what you could do to confirm that there are button items will be shown in the navigation item is to let the bar button item to has a custom view. Adding a UIButton as a custom view for UIBarButtonItem would be valid, like this:

// right
let rightButton = UIButton(type: .custom)
rightButton.setTitle("Button.Done".localized, for: .normal)
rightButton.addTarget(self, action: #selector(saveButtonTapped), for: .touchUpInside)
let rightBarButtonItem = UIBarButtonItem(customView: rightButton)
navigationItem.setRightBarButton(rightBarButtonItem, animated: true)

// left
let leftButton = UIButton(type: .custom)
leftButton.setTitle("Button.Cancel".localized, for: .normal)
leftButton.addTarget(self, action: #selector(cancelButtonTapped), for: .touchUpInside)
let leftBarButtonItem = UIBarButtonItem(customView: leftButton)
navigationItem.setLeftBarButton(leftBarButtonItem, animated: true)

因此，对于任何需要的 UI 更新，您可以编辑 rightButton 和 leftButton，例如:

Therefore, for any needed UI update, you could edit rightButton and leftButton, example:

leftButton.layer.backgroundColor = UIColor.red.cgColor
leftButton.layer.borderWidth = 2.0
leftButton.layer.borderColor = UIColor.black.cgColor

此外，我认为没有必要调用:

In addition, I would assume that there is no need to call:

self.navigationItem.setHidesBackButton(isBackHidden, animated: false)

设置左栏按钮项时，默认应该替换后退按钮.

When setting the left bar button item, it should be a replacement for the back button by default.

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