禁用/隐藏辅助功能元素

Question

我试图从 VoiceOver 隐藏我的应用程序中的几个元素，以便屏幕阅读器不会大声朗读它们。在 iOS 上，我设置isAccessibilityElement为NO，但这对 OSX 没有影响。从 VoiceOver 隐藏元素的正确方法是什么？

例如，我在视图中包含了一系列标签，如果它们被 VoiceOver 单独朗读，则这些标签毫无意义。我想accessibilityLabel在容器视图上设置来描述嵌套在其中的所有标签。但是如果我这样做，里面的标签仍然会被 VoiceOver 读出。

Answer 1

In macOS, it is true that setting accessibilityElement to NO for NSButton, NSTextField and NSImageView has no effect. That is because these are controls – they inherit from NSControl. To make it work for controls, you must do it instead to the control's cell.

In an Objective-C project, I so subclassed several Cocoa controls. For example, whenever I want a image view to be skipped by VoiceOver, I set its Custom Class in Interface Builder to this:

/*!
 @brief    Image view which will be skipped over by VoiceOver

 @details  Be careful that you *really* want the view to be skipped over by
 VoiceOver, because its meaning is conveyed in a better, non-visual way,
 elsewhere.  Remember that not all VoiceOver users are completely blind.
  */
@interface SSYNoVoiceOverImageView : NSImageView {}
@end

@implementation SSYNoVoiceOverImageView

- (void)awakeFromNib {
    self.cell.accessibilityElement = NO;
}

@end

Answer 2

如果将元素的辅助功能角色设置为空字符串，Voice Over 将不会检测到它。我必须在应用程序中隐藏一些 NSImageView 元素，因为它们的文件名正在被读出，这会让 VO 用户感到困惑。

任何一个

[element accessibilitySetOverrideValue:@"" forAttribute:NSAccessibilityRoleAttribute];

要不然

[[element cell] accessibilitySetOverrideValue:@"" forAttribute:NSAccessibilityRoleAttribute];

应该可以解决问题。

我知道 Apple 提供了一种基于 Accessibility API 的新方法，但它仅适用于 OS X 10.10 及以上版本，而我正在使用的应用程序需要与 10.9 兼容。

如果你可以使用新的 API [element setAccessibilityRole:@""];或者[[element cell] setAccessibilityRole:@""];应该做同样的事情。