如何在出现覆盖时禁用 main UI？

Question

我构建了一个如下所示的流式音频应用程序：

当流丢失时，我覆盖这个屏幕：

我的问题是，在启用画外音的情况下，所有底层控件仍然处于活动状态：我可以向它们滑动，并调整它们的值。

这是我在信号丢失和恢复时的代码片段：

@objc func lostStream() {
    DispatchQueue.main.async {
        self.lossOfSignalBlocker.alpha = 0.0
        self.lossOfSignalBlocker.frame = self.view.bounds
        self.view.addSubview(self.lossOfSignalBlocker)
        self.lossOfSignalBlocker.isUserInteractionEnabled = true
        //UIView.animate(withDuration: 0.2) { self.lossOfSignalBlocker.alpha = 1.0 }
        UIView.animate( withDuration: 0.2, animations: { self.lossOfSignalBlocker.alpha = 1.0 } )

        //Announce loss of signal to Voiceover user.
        UIAccessibilityPostNotification(
            UIAccessibilityAnnouncementNotification,
            "Signal Lost" as NSString
        )
    }
}

@objc func regainedStream() {
    DispatchQueue.main.async {
        UIView.animate( withDuration: 0.2, animations: { self.lossOfSignalBlocker.alpha = 0.0 } )
        { _ in
            self.lossOfSignalBlocker.removeFromSuperview()
        }
    }
}

如何禁用主要 UI 以便只有叠加响应任何与画外音相关的操作？

Answer 1

在 UIAccessibility 个元素（例如视图）上，有一个名为 accessibilityElementsHidden 的属性。将此值设置为 true 应该隐藏被 "reconnecting" 视图覆盖的视图。

考虑在后台 UITableView 上将 this 值设置为 true。

有关详细信息，请查看文档：https://developer.apple.com/documentation/objectivec/nsobject/1615080-accessibilityelementshidden

Answer 2

好的！我已经成功了。除了将 'accessibilityElementsHidden' 设置为 TRUE 之外，您还必须通过调用带有 'UIAccessibilityScreenChangedNotification' 通知的 'UIAccessibilityPostNotification' 来告诉应用程序屏幕已更改。

现在的代码如下所示：

@objc func lostStream() {
    DispatchQueue.main.async {

        self.lossOfSignalBlocker.alpha = 0.0
        self.lossOfSignalBlocker.frame = self.view.bounds
        self.view.addSubview(self.lossOfSignalBlocker)
        self.lossOfSignalBlocker.isUserInteractionEnabled = true
        UIView.animate( withDuration: 0.1, animations: { self.lossOfSignalBlocker.alpha = 1.0 } )

        //Disable Voiceover accessibility controls in main view
        self.tableView.accessibilityElementsHidden = true

        //Notify app the screen has changed.
        UIAccessibilityPostNotification(
            UIAccessibilityScreenChangedNotification,
            nil
        )

        //Announce loss of signal to Voiceover user.
        UIAccessibilityPostNotification(
            UIAccessibilityAnnouncementNotification,
            "Signal Lost. Reconnecting." as NSString
        )

    }
}

@objc func regainedStream() {
    DispatchQueue.main.async {

        UIView.animate( withDuration: 0.2, animations: { self.lossOfSignalBlocker.alpha = 0.0 } )
        { _ in
            self.lossOfSignalBlocker.removeFromSuperview()
        }

        //Re-enable Voiceover accessibility controls in main view
        self.tableView.accessibilityElementsHidden = false

        //Notify app the screen has changed.
        UIAccessibilityPostNotification(
            UIAccessibilityScreenChangedNotification,
            nil
        )

        //Announce signal regained to Voiceover user.
        UIAccessibilityPostNotification(
            UIAccessibilityAnnouncementNotification,
            "Reconnected." as NSString
        )

    }
}

如何在出现覆盖时禁用 main UI？

How to disable main UI when overlay appears?

ios

swift

uiview

voiceover

subviews