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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
commit | 33058f2b292b3a581333bdfb21b8f671898c5060 (patch) | |
tree | 51c3e392513ec574331b2d3f85c394445ea803c6 /files/zh-cn/web/api/mediadevices/enumeratedevices | |
parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
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diff --git a/files/zh-cn/web/api/mediadevices/enumeratedevices/index.html b/files/zh-cn/web/api/mediadevices/enumeratedevices/index.html new file mode 100644 index 0000000000..02a65eb991 --- /dev/null +++ b/files/zh-cn/web/api/mediadevices/enumeratedevices/index.html @@ -0,0 +1,93 @@ +--- +title: MediaDevices.enumerateDevices() +slug: Web/API/MediaDevices/enumerateDevices +tags: + - API + - WebRTC + - 方法 +translation_of: Web/API/MediaDevices/enumerateDevices +--- +<div>{{APIRef("WebRTC")}}</div> + +<p>{{domxref("MediaDevices")}} 的方法 <strong><code>enumerateDevices()</code></strong> 请求一个可用的媒体输入和输出设备的列表,例如麦克风,摄像机,耳机设备等。 返回的 {{domxref("Promise")}} 完成时,会带有一个描述设备的 {{domxref("MediaDeviceInfo")}} 的数组。</p> + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox">var <em>enumeratorPromise</em> = navigator.mediaDevices.enumerateDevices(); +</pre> + +<h3 id="返回值">返回值</h3> + +<p>返回一个 {{ domxref("Promise") }} 。当完成时,它接收一个 {{domxref("MediaDeviceInfo")}} 对象的数组。每个对象描述一个可用的媒体输入输出设备。.</p> + +<p>如果枚举失败,promise 也会被拒绝(rejected)。</p> + +<h2 id="示例">示例</h2> + +<p>这是一个使用 <code>enumerateDevices()</code> 的例子。它只是输出一个带有标签(有标签的情况下)的 <a href="/zh-CN/docs/Web/API/MediaDeviceInfo/deviceId">device ID</a> 的列表。</p> + + + +<pre class="brush: js">if (!navigator.mediaDevices || !navigator.mediaDevices.enumerateDevices) { + console.log("不支持 enumerateDevices() ."); + return; +} + +// 列出相机和麦克风。 + +navigator.mediaDevices.enumerateDevices() +.then(function(devices) { + devices.forEach(function(device) { + console.log(device.kind + ": " + device.label + + " id = " + device.deviceId); + }); +}) +.catch(function(err) { + console.log(err.name + ": " + err.message); +});</pre> + +<p>这将会输出类似以下的内容:</p> + +<pre>videoinput: id = csO9c0YpAf274OuCPUA53CNE0YHlIr2yXCi+SqfBZZ8= +audioinput: id = RKxXByjnabbADGQNNZqLVLdmXlS0YkETYCIbg+XxnvM= +audioinput: id = r2/xw1xUPIyZunfV1lGrKOma5wTOvCkWfZ368XCndm0= +</pre> + +<p>或者,如果有一个或多个 {{domxref("MediaStream")}} 处于活动状态或者获得了持久授权,将会输出以下内容:</p> + +<pre>videoinput: FaceTime HD Camera (Built-in) id=csO9c0YpAf274OuCPUA53CNE0YHlIr2yXCi+SqfBZZ8= +audioinput: default (Built-in Microphone) id=RKxXByjnabbADGQNNZqLVLdmXlS0YkETYCIbg+XxnvM= +audioinput: Built-in Microphone id=r2/xw1xUPIyZunfV1lGrKOma5wTOvCkWfZ368XCndm0= +</pre> + +<h2 id="规范">规范</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">规范</th> + <th scope="col">状态</th> + <th scope="col">注释</th> + </tr> + <tr> + <td>{{SpecName('Media Capture', '#dom-mediadevices-enumeratedevices', 'mediaDevices: enumerateDevices')}}</td> + <td>{{Spec2('Media Capture')}}</td> + <td>Initial definition.</td> + </tr> + </tbody> +</table> + +<h2 id="浏览器兼容性">浏览器兼容性</h2> + + + +<div>{{Compat("api.MediaDevices.enumerateDevices")}}</div> + +<h2 id="See_also">See also</h2> + +<ul> + <li>{{domxref("navigator.mediaDevices.getUserMedia()")}}</li> + <li><a href="/zh-CN/docs/WebRTC" title="WebRTC">WebRTC</a> - the introductory page to the API</li> + <li><a href="/zh-CN/docs/WebRTC/MediaStream_API" title="WebRTC/MediaStream_API">MediaStream API</a> - the API for the media stream objects</li> + <li><a href="/zh-CN/docs/WebRTC/taking_webcam_photos" title="WebRTC/taking_webcam_photos">Taking webcam photos</a> - a tutorial on using <code>getUserMedia()</code> for taking photos rather than video.</li> +</ul> |