HarmonyOS 鸿蒙Next 在WebView中通过getUserMedia打开摄像头失败

HarmonyOS 鸿蒙Next 在WebView中通过getUserMedia打开摄像头失败

config.json已经配置如下权限：

      ....
      {
        "name": "ohos.permission.CAMERA"
      },
      {
        "name": "ohos.permission.WRITE_MEDIA"
      },
      {
        "name": "ohos.permission.MODIFY_AUDIO_SETTINGS"
      },
      {
        "name": "ohos.permission.MEDIA_LOCATION"
      },
      {
        "name": "ohos.permission.MANAGE_USER_STORAGE"
      },
      {
        "name": "ohos.permission.MICROPHONE"
      },
      ....

MainAbility.java添加了如下代码：

    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);
        // 省略若干代码
        webView = (WebView)findViewById(ResourceTable.Id_webView);
        webView.getWebConfig().setJavaScriptPermit(true);
        webView.getWebConfig().setSecurityMode(webView.getWebConfig().SECURITY_ALLOW);
        webView.getWebConfig().setDataAbilityPermit(true);
        webView.getWebConfig().setLoadsImagesPermit(true);
        webView.getWebConfig().setLocationPermit(true);
        webView.getWebConfig().setMediaAutoReplay(true);
        webView.getWebConfig().setWebStoragePermit(true);
        // 省略若干代码
    }
      ....

index.html关键内容如下：

<button onclick="showCamera()">开启摄像头</button>
<div class="bg-content" style="display: none;">
    <div class="show-photo">
        <video id="video" controls=true width="300px" height="400px" autoplay=false></video>
        <canvas id="canvas" width="300px" height="400px" style="display: none;"></canvas>
        <a id="downloadA"></a>
    </div>
</div>

其中showCamera()对应js代码为：

function showCamera() {
    $(".bg-content").css("display", "block");
    let constraints = {
        video: {
            width: 600,
            height: 600,
            facingMode: 'environment' // 后置摄像头
        },
        audio: true
    };
    //获得video摄像头区域
    let video = document.getElementById("video");
    // 这个Promise对象返回成功后的回调函数带一个 MediaStream 对象作为其参数
    let promise = navigator.mediaDevices.getUserMedia(constraints);
    
    console.log(navigator.mediaDevices)
    console.log('open media stream...')

    promise.then(function(MediaStream) {
        console.log('open media stream!')
        mediaStreamTrack = typeof MediaStream.stop === 'function' ? MediaStream : MediaStream.getTracks()[1];
        // video.srcObject = MediaStream;
        video.src = window.URL && window.URL.createObjectURL(MediaStream) || MediaStream
        video.muted = true;
        video.play();
    });
}

最后的 异常表现为video组件黑屏 上述代码部分借鉴网上资料，请求帮忙看看