XRSystem: devicechange event

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用法注意事项
范例
规范
浏览器兼容性
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A devicechange event is fired on an XRSystem object whenever the whenever the availability of immersive XR devices has changed; for example, a VR headset or AR goggles have been connected or disconnected. It's a generic 事件 with no added properties.

注意： Not to be confused with the MediaDevices devicechange 事件。

冒泡	No
可取消	No
接口	`事件`
Event handler	`XRSystem.ondevicechange`

用法注意事项

devicechange events are not delivered if the document which owns the XRSystem object has been granted permission to do so through the xr-spatial-tracking feature policy.

You can use this event to, for example, monitor for the availability of a WebXR-compatible device so that you can enable a UI element which the user can use to activate immersive mode. This is shown in the 范例下文。

范例

The example shown here handles the devicechange event by toggling the availability of the "Enter XR" button based on whether or not any immersive devices are currently available.

if (navigator.xr) {
  navigator.xr.addEventListener("devicechange", event => {
    navigator.xr.isSessionSupported("immersive-vr")
    .then(immersiveOK) => {
      if (immersiveOK) {
        enableXRButton.disabled = false;
      } else {
        enableXRButton.disabled = true;
      }
    });
  });
}

当 devicechange is received, the handler set up in this code calls the XR 方法 isSessionSupported() to find out if there's a device available that can handle immersive VR presentations. If there is, the button to enter XR mode is enabled; otherwise it's disabled.

还可以使用 ondevicechange event handler property to set a single handler for devicechange 事件：

if (navigator.xr) {
  navigator.xr.ondevicechange = event => {
    /* ... etc ... */
  };
}

规范

规范	状态	注释
WebXR 设备 API The definition of 'devicechange event' in that specification.	工作草案	初始定义。

浏览器兼容性

更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`devicechange` event	Chrome 79	Edge 79	Firefox No	IE No	Opera No	Safari No	WebView Android No	Chrome Android 79	Firefox Android No	Opera Android No	Safari iOS No	Samsung Internet Android 11.2

图例

完整支持
不支持
实验。期望将来行为有所改变。

另请参阅

XRSystem.ondevicechange

元数据

最后修改： Feb 27, 2020

WebXR 设备 API
XRSystem
方法
1. XRSystem: isSessionSupported()
2. XRSystem: requestSession()
Related pages for WebXR Device API

在此页

用法注意事项

范例

规范

浏览器兼容性

图例

另请参阅

相关话题