尝试重新加载视图控制器以更新当前主题 [英] Trying to reload view controller to update the current theme

问题描述

我试图重新加载视图控制器中的所有视图，以在主题之间进行更改(类似于Twitter或Apple Maps所做的事情.)

I am trying to reload all the views in my view controller, to change between themes (similar to what Twitter or Apple Maps does).

我的主题视图设置如下:

I have themed views setup like so:

@IBDesignable
extension UIView {

    @IBInspectable
    var lightBackgroundColor: UIColor? {
        set {
            switch GEUserSettings.theme {
            case .light:    backgroundColor = newValue
            case .dark:     break
            }
        }
        get {
            return self.lightBackgroundColor
        }
    }

    @IBInspectable
    var darkBackgroundColor: UIColor? {
        set {
            switch GEUserSettings.theme {
            case .light:    break
            case .dark:     backgroundColor = newValue
            }
        }
        get {
            return self.darkBackgroundColor
        }
    }
}

这允许我在Main.storyboard中根据当前主题设置light和dark主题背景颜色.我的背景模糊效果被排除在外，因为我找不到在代码中更新style的方法，所以它是在viewDidLoad中创建的.

This allows me in my Main.storyboard to set a light and dark theme background colour, depending on the current theme. My background blur effect is excluded from this, as I couldn't find a way to update the style in code, so it is created in viewDidLoad.

但是，当我想更改主题时，我不确定该怎么做.我想通过摇动设备来触发它，就像这样:

However, when I want to change the theme, I'm not sure how to do it. I want to trigger it from shaking the device, like so:

override func motionBegan(_ motion: UIEvent.EventSubtype, with event: UIEvent?) {
    print("Shaken!")
    let oppositeTheme: GEUserSettings.Theme = {
        switch GEUserSettings.theme {
        case .light:    return .dark
        case .dark:     return .light
        }
    }()

    GEUserSettings.theme = oppositeTheme

    // My attempt to update the view controller to
    // update the theme, which doesn't do anything.
    dismiss(animated: true) {
        UIApplication.shared.keyWindow?.rootViewController?.present(self, animated: true, completion: nil)
        // Yes, the presenting is working, but the views don't change.
    }
}

---

可能的解决方案是什么?

如果退出并重新启动该应用程序，设置将生效.我可以强制退出该应用程序(不使用exit(0)或任何会导致崩溃的东西)，也可以在使用该应用程序时重新加载它.

---

What are the possible solutions?

The settings take effect if the app is quit and relaunched. I could either force the app to quit (not using exit(0) or anything that counts as a crash), or reload it whilst using the app.

我尝试关闭然后重新加载视图控制器，如上面的代码所示.我正在重新加载的一个显示在基本视图控制器的顶部.

I tried to dismiss and then reload the view controller, as shown in the code above. The one I am reloading is presented on top of the base view controller.

当我使用情节提要板时，该如何进行这项工作?

How can I make this work, as I am using storyboards?

编辑-添加了我的明/暗模式的图像，使我的问题更清晰:

Edit - Added an image of my light/dark modes to make my question clearer:

推荐答案

我终于使用NotificationCenter弄清楚了！

GEUserSettings现在如下所示:

enum GEUserSettings {

    enum Theme: String {
        case light
        case dark
    }
    /// The current theme for the user.
    static var theme: Theme = .dark
    #warning("Store theme in UserDefaults")

    /// Toggles the theme.
    static func toggleTheme() {
        switch GEUserSettings.theme {
        case .light:    theme = .dark
        case .dark:     theme = .light
        }

        NotificationCenter.default.post(name: Notification.Name("UpdateThemeNotification"), object: nil)
    }
}

GEView

GEView是我的UIView自定义子类.这是替代品，而不是我对UIView的扩展.现在看起来与此类似:

GEView

GEView is my custom subclass of UIView. This is a replacement instead of my extension to UIView. It now looks similar to this:

/// UIView subclass to allow creating corners, shadows, and borders in storyboards.
@IBDesignable
final class GEView: UIView {

    // MARK: - Initializers
    override init(frame: CGRect) {
        super.init(frame: frame)
    }
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        // Triggers when the theme is changed
        NotificationCenter.default.addObserver(self, selector: #selector(updateBackgroundColorNotification), name: Notification.Name("UpdateThemeNotification"), object: nil)
    }
    @objc
    private func updateBackgroundColorNotification() {
        updateBackgroundColor()
    }


    /* ... */


    // MARK: - Background
    @IBInspectable
    var lightBackgroundColor: UIColor? {
        didSet {
            updateBackgroundColor()
        }
    }
    @IBInspectable
    var darkBackgroundColor: UIColor? {
        didSet {
            updateBackgroundColor()
        }
    }

    /// Updates the background color depending on the theme.
    private func updateBackgroundColor() {
        switch GEUserSettings.theme {
        case .light:    backgroundColor = self.lightBackgroundColor
        case .dark:     backgroundColor = self.darkBackgroundColor
        }
    }
}

通过motionBegan(_:with:)

更新

Updating through motionBegan(_:with:)

override func motionBegan(_ motion: UIEvent.EventSubtype, with event: UIEvent?) {
    super.motionBegan(motion, with: event)

    // Toggles the theme and update the views
    GEUserSettings.toggleTheme()
    drawerViewModel.updateBlurEffect(drawerView: drawerView)
}

然后将模糊移除并重新创建，如下所示:

And the blur is removed and recreated, as such:

/// Creates the blur effect behind the collection view.
func updateBlurEffect(drawerView: GEView) {
    if let blurView = drawerView.subviews[0] as? UIVisualEffectView {
        blurView.removeFromSuperview()
    }

    let blurEffect: UIBlurEffect = {
        switch GEUserSettings.theme {
        case .light:    return UIBlurEffect(style: .light)
        case .dark:     return UIBlurEffect(style: .dark)
        }
    }()
    let blurView = UIVisualEffectView(effect: blurEffect)

    drawerView.addSubview(blurView)
    drawerView.sendSubviewToBack(blurView)
    GEConstraints.fillView(with: blurView, for: drawerView)
}

---

这甚至不需要退出应用程序或重新加载视图控制器，它会立即发生！

---

This doesn't even require quitting the app or reloading the view controller, it happens instantly!

如果愿意，还可以通过更改updateBackgroundColor()功能来设置颜色变化的动画:

If you wish, you can also animate the color change by changing the updateBackgroundColor() function:

/// Updates the background color depending on the theme.
private func updateBackgroundColor() {
    UIView.animate(withDuration: 0.25) {
        switch GEUserSettings.theme {
        case .light:    self.backgroundColor = self.lightBackgroundColor
        case .dark:     self.backgroundColor = self.darkBackgroundColor
        }
    }
}

您还可以为模糊设置动画:

You can also animate the blur as well:

/// Creates the blur effect behind the collection view.
func updateBlurEffect(drawerView: GEView) {
    if let blurView = drawerView.subviews[0] as? UIVisualEffectView {
        UIView.animate(withDuration: 0.25, animations: {
            blurView.alpha = 0
        }, completion: { _ in
            blurView.removeFromSuperview()
        })
    }

    let blurEffect: UIBlurEffect = {
        switch GEUserSettings.theme {
        case .light:    return UIBlurEffect(style: .light)
        case .dark:     return UIBlurEffect(style: .dark)
        }
    }()
    let blurView = UIVisualEffectView(effect: blurEffect)
    blurView.alpha = 0

    drawerView.addSubview(blurView)
    drawerView.sendSubviewToBack(blurView)
    GEConstraints.fillView(with: blurView, for: drawerView)

    UIView.animate(withDuration: 0.25, animations: {
        blurView.alpha = 1
    })
}

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