无障碍性 Accessibility

获取页面的当前高对比度模式。

Gets the current high-contrast-mode for the page.

为宿主元素添加一个由 aria-describedby 引用的不可见的消息元素。如果已经注册了相同的消息，则它将复用已创建的消息元素。

Adds to the host element an aria-describedby reference to a hidden element that contains the message. If the same message has already been registered, then it will reuse the created message element.

为宿主元素添加一个由 aria-describedby 引用的现有消息元素。

Adds to the host element an aria-describedby reference to an already-existing message element.

在指定元素周围创建一个焦点捕获 zone 。

Creates a focus-trapped region around the given element.

在指定元素周围创建一个焦点捕获区域。

Creates a focus-trapped region around the given element.

获取元素是否被禁用。

Gets whether an element is disabled.

获取用户是否可以给某个元素设置焦点。

Gets whether an element can be focused by the user.

获取是否可以通过 Tab 键访问元素。假定已经使用 isFocusable 检查过此元素。

Gets whether an element can be reached via Tab key. Assumes that the element has already been checked with isFocusable.

获取某元素可见是否出于交互目的。

Gets whether an element is visible for the purposes of interactivity.

这包括 display: none 和 visibility: hidden 状态下的，但被 overflow: hidden 的父对象切掉或位于视口之外的除外。

This will capture states like display: none and visibility: hidden, but not things like being clipped by an overflow: hidden parent or being outside the viewport.

向屏幕阅读器发布一条消息。

Announces a message to screenreaders.

向屏幕阅读器发布一条消息。

Announces a message to screenreaders.

向屏幕阅读器发布一条消息。

Announces a message to screenreaders.

向屏幕阅读器发布一条消息。

Announces a message to screenreaders.

从播音员元素中清除当前文本。可以用于防止屏幕阅读器在用户浏览页面地标时再次读出文本。

Clears the current text from the announcer element. Can be used to prevent screen readers from reading the text out again while the user is going through the page landmarks.

通过指定的焦点来源对元素进行聚焦。

Focuses the element via the specified focus origin.

通过指定的焦点来源对元素进行聚焦。

Focuses the element via the specified focus origin.

监视元素的焦点，并应用适当的 CSS 类。

Monitors focus on an element and applies appropriate CSS classes.

监视元素的焦点，并应用适当的 CSS 类。

Monitors focus on an element and applies appropriate CSS classes.

获取用户当前是否正在使用预输入函数键入此管理员。

Gets whether the user is currently typing into the manager using the typeahead feature.

根据传入的键盘事件设置激活条目。

Sets the active item depending on the key event passed in.

将活动条目设置为指定索引处的条目，并将活动样式添加到新活动条目。也会从以前的活动条目中删除活动样式。

Sets the active item to the item at the specified index and adds the active styles to the newly active item. Also removes active styles from the previously active item.

将活动条目设置为指定的条目，并将活动样式添加到该条目。也从以前的活动条目中删除活动样式。

Sets the active item to the item to the specified one and adds the active styles to the it. Also removes active styles from the previously active item.

将激活条目设置为列表中第一个可用的（enabled）条目。

Sets the active item to the first enabled item in the list.

将激活条目设置为列表中最后一个可用的（enabled）条目。

Sets the active item to the last enabled item in the list.

将激活条目设置为列表中的下一个可用的（enabled）条目。

Sets the active item to the next enabled item in the list.

将激活条目设置为列表中的上一个可用的（enabled）条目。

Sets the active item to a previous enabled item in the list.

设置谓词函数，该函数会确定列表按键管理器应跳过哪些条目。

Sets the predicate function that determines which items should be skipped by the list key manager.

允许在没有任何其他效果的情况下设置激活状态。

Allows setting the active without any other effects.

允许设置活动条目，而没有任何其他影响。

Allows setting the active item without any other effects.

用户按下方向键时，可以按住修饰键并防止其默认操作。默认为不允许任何修饰键。

Modifier keys which are allowed to be held down and whose default actions will be prevented as the user is pressing the arrow keys. Defaults to not allowing any modifier keys.

配置按键管理器，以在按下 Home 或 End 键时分别激活第一项和最后一项。

Configures the key manager to activate the first and last items respectively when the Home or End key is pressed.

配置按键管理器以水平移动选择。传递 null 将禁用水平移动。

Configures the key manager to move the selection horizontally. Passing in null will disable horizontal movement.

打开预输入模式，该模式允许用户通过键入来设置活动条目。

Turns on typeahead mode which allows users to set the active item by typing.

配置按键管理器是否应该能够垂直移动选择。

Configures whether the key manager should be able to move the selection vertically.

配置回卷模式，当该模式确定在指定方向上没有更多条目时，活动条目是否将回卷列表的另一端。

Configures wrapping mode, which determines whether the active item will wrap to the other end of list when there are no more items in the given direction.

获取用户当前是否正在使用预输入函数键入此管理员。

Gets whether the user is currently typing into the manager using the typeahead feature.

根据传入的键盘事件设置激活条目。

Sets the active item depending on the key event passed in.

将活动条目设置为指定索引处的条目，并让新的活动条目获得焦点。

Sets the active item to the item at the specified index and focuses the newly active item.

将活动条目设置为指定的条目并让它获得焦点。

Sets the active item to the item that is specified and focuses it.

将激活条目设置为列表中第一个可用的（enabled）条目。

Sets the active item to the first enabled item in the list.

设置焦点来源，该焦点来源将传递给所有后续调用 focus 的条目。

Sets the focus origin that will be passed in to the items for any subsequent focus calls.

将激活条目设置为列表中最后一个可用的（enabled）条目。

Sets the active item to the last enabled item in the list.

将激活条目设置为列表中的下一个可用的（enabled）条目。

Sets the active item to the next enabled item in the list.

将激活条目设置为列表中的上一个可用的（enabled）条目。

Sets the active item to a previous enabled item in the list.

设置谓词函数，该函数会确定列表按键管理器应跳过哪些条目。

Sets the predicate function that determines which items should be skipped by the list key manager.

允许在没有任何其他效果的情况下设置激活状态。

Allows setting the active without any other effects.

允许设置活动条目，而没有任何其他影响。

Allows setting the active item without any other effects.

用户按下方向键时，可以按住修饰键并防止其默认操作。默认为不允许任何修饰键。

Modifier keys which are allowed to be held down and whose default actions will be prevented as the user is pressing the arrow keys. Defaults to not allowing any modifier keys.

配置按键管理器，以在按下 Home 或 End 键时分别激活第一项和最后一项。

Configures the key manager to activate the first and last items respectively when the Home or End key is pressed.

配置按键管理器以水平移动选择。传递 null 将禁用水平移动。

Configures the key manager to move the selection horizontally. Passing in null will disable horizontal movement.

打开预输入模式，该模式允许用户通过键入来设置活动条目。

Turns on typeahead mode which allows users to set the active item by typing.

配置按键管理器是否应该能够垂直移动选择。

Configures whether the key manager should be able to move the selection vertically.

配置回卷模式，当该模式确定在指定方向上没有更多条目时，活动条目是否将回卷列表的另一端。

Configures wrapping mode, which determines whether the active item will wrap to the other end of list when there are no more items in the given direction.

获取用户当前是否正在使用预输入函数键入此管理员。

Gets whether the user is currently typing into the manager using the typeahead feature.

根据传入的键盘事件设置激活条目。

Sets the active item depending on the key event passed in.

把激活条目设置为由索引指定的条目。

Sets the active item to the item at the index specified.

将活动条目设置为指定的条目。

Sets the active item to the specified item.

将激活条目设置为列表中第一个可用的（enabled）条目。

Sets the active item to the first enabled item in the list.

将激活条目设置为列表中最后一个可用的（enabled）条目。

Sets the active item to the last enabled item in the list.

将激活条目设置为列表中的下一个可用的（enabled）条目。

Sets the active item to the next enabled item in the list.

将激活条目设置为列表中的上一个可用的（enabled）条目。

Sets the active item to a previous enabled item in the list.

设置谓词函数，该函数会确定列表按键管理器应跳过哪些条目。

Sets the predicate function that determines which items should be skipped by the list key manager.

允许在没有任何其他效果的情况下设置激活状态。

Allows setting the active without any other effects.

允许设置活动条目，而没有任何其他影响。

Allows setting the active item without any other effects.

用户按下方向键时，可以按住修饰键并防止其默认操作。默认为不允许任何修饰键。

Modifier keys which are allowed to be held down and whose default actions will be prevented as the user is pressing the arrow keys. Defaults to not allowing any modifier keys.

配置按键管理器，以在按下 Home 或 End 键时分别激活第一项和最后一项。

Configures the key manager to activate the first and last items respectively when the Home or End key is pressed.

配置按键管理器以水平移动选择。传递 null 将禁用水平移动。

Configures the key manager to move the selection horizontally. Passing in null will disable horizontal movement.

打开预输入模式，该模式允许用户通过键入来设置活动条目。

Turns on typeahead mode which allows users to set the active item by typing.

配置按键管理器是否应该能够垂直移动选择。

Configures whether the key manager should be able to move the selection vertically.

配置回卷模式，当该模式确定在指定方向上没有更多条目时，活动条目是否将回卷列表的另一端。

Configures wrapping mode, which determines whether the active item will wrap to the other end of list when there are no more items in the given direction.

将这些锚点插入 DOM。这通常是在构造函数中自动完成的，但是对于诸如 *ngIf 之类的指令，可以将其推迟。

Inserts the anchors into the DOM. This is usually done automatically in the constructor, but can be deferred for cases like directives with *ngIf.

通知 FocusTrapManager，此 FocusTrap 将被销毁。

Notifies the FocusTrapManager that this FocusTrap will be destroyed.

让焦点陷阱范围内第一个可 tab 的元素获得焦点。

Focuses the first tabbable element within the focus trap region.

等待 zone 稳定，然后让焦点陷阱内第一个可 tab 的元素获得焦点。

Waits for the zone to stabilize, then focuses the first tabbable element within the focus trap region.

在初始化焦点陷阱时应获得焦点的元素。

Focuses the element that should be focused when the focus trap is initialized.

等待 zone 稳定，然后聚焦用户指定的第一个元素或第一个可 tab 的元素。

Waits for the zone to stabilize, then either focuses the first element that the user specified, or the first tabbable element.

让焦点陷阱范围内最后一个可 tab 的元素获得焦点。

Focuses the last tabbable element within the focus trap region.

等待 zone 稳定，然后让焦点陷阱内最后一个可 tab 的元素获得焦点。

Waits for the zone to stabilize, then focuses the last tabbable element within the focus trap region.

检查焦点陷阱是否已附加成功。

Checks whether the focus trap has successfully been attached.

删除在 preventFocus 中添加的事件侦听器。

Removes the event listener added in preventFocus.

添加一个文档事件监听器，使焦点保持在 FocusTrap 内部。

Adds a document event listener that keeps focus inside the FocusTrap.

将这些锚点插入 DOM。这通常是在构造函数中自动完成的，但是对于诸如 *ngIf 之类的指令，可以将其推迟。

Inserts the anchors into the DOM. This is usually done automatically in the constructor, but can be deferred for cases like directives with *ngIf.

清理锚点以销毁焦点陷阱。

Destroys the focus trap by cleaning up the anchors.

让焦点陷阱范围内第一个可 tab 的元素获得焦点。

Focuses the first tabbable element within the focus trap region.

等待 zone 稳定，然后让焦点陷阱内第一个可 tab 的元素获得焦点。

Waits for the zone to stabilize, then focuses the first tabbable element within the focus trap region.

在初始化焦点陷阱时应获得焦点的元素。

Focuses the element that should be focused when the focus trap is initialized.

等待 zone 稳定，然后聚焦用户指定的第一个元素或第一个可 tab 的元素。

Waits for the zone to stabilize, then either focuses the first element that the user specified, or the first tabbable element.

让焦点陷阱范围内最后一个可 tab 的元素获得焦点。

Focuses the last tabbable element within the focus trap region.

等待 zone 稳定，然后让焦点陷阱内最后一个可 tab 的元素获得焦点。

Waits for the zone to stabilize, then focuses the last tabbable element within the focus trap region.

检查焦点陷阱是否已附加成功。

Checks whether the focus trap has successfully been attached.

切换 tabindex 以捕获 Tab 焦点或允许脱离。

Toggles thetabindex of both anchors to either trap Tab focus or allow it to escape.

将活动条目的样式应用于此条目。

Applies the styles for an active item to this item.

将非活动条目的样式应用于此条目。

Applies the styles for an inactive item to this item.

让此 FocusableOption 获得焦点。

Focuses the FocusableOption.

获取此选项的标签。

Gets the label for this option.

通过 preventFocus 以前的状态，来把元素恢复为不可获得焦点的状态。

Reverts elements made unfocusable by preventFocus to their previous state.

使 focusTrap 之外的所有元素都无法获得焦点。

Makes all elements outside focusTrap unfocusable.

当使用键盘激活可获得焦点的元素时，屏幕阅读器通常会触发一个伪 mousedown 事件。我们通常可以使用 “buttons” 属性来区分这些伪 mousedown 事件和真实的 mousedown 事件。真实的 mousedown 会指出被按下的鼠标按键（比如鼠标左键是“1”），而伪造的 mousedown 通常会把该属性值设置为 0。

Screenreaders will often fire fake mousedown events when a focusable element is activated using the keyboard. We can typically distinguish between these faked mousedown events and real mousedown events using the "buttons" property. While real mousedowns will indicate the mouse button that was pressed (e.g. "1" for the left mouse button), faked mousedowns will usually set the property value to 0.