android webview实现拍照

<div id="pnlVideo1">
                            <input type="hidden" name="imgNric1" id="imgNric1" />
                            <label id="nric" class="control-label labelfont" style="color:#888;font-weight:bold;">Picture of Asset</label><br /><br />
                            <button id="btnOpen1" class="btn btn-default" type="button">Open WebCam</button>
                            <select id="videoSource" style="display:none">
                                
                            </select>
                            <div id="vdoOne" style="display:none;">
                                <video id="video" style="margin-top:15px;margin-bottom:15px;" width="300" autoplay></video>
                                <canvas id="canvasPreview" style="margin-top:15px;" width="300" height="224"></canvas>
                                <canvas id="canvasUpload" style="display:none;" width='300' height='224'></canvas>
                                <button id="snap" class="btn btn-default" type="button">Snap Photo</button>
                            </div>
                        </div>
                       
                        






    <script type="text/javascript">
        $(document).ready(function () {




        });


         Elements for taking the snapshot
        var canvasPreview = document.getElementById('canvasPreview');
        var canvasUpload = document.getElementById('canvasUpload');
        var contextPreview = canvasPreview.getContext('2d');
        var contextUpload = canvasUpload.getContext('2d');






        //#################### Video Source #######################
        var videoElement = document.querySelector('video');
        var videoSelect = document.querySelector('select#videoSource');


        navigator.mediaDevices.enumerateDevices()
            .then(gotDevices).then(getStream).catch(handleError);


        videoSelect.onchange = getStream;


        function gotDevices(deviceInfos) {
            for (var i = 0; i !== deviceInfos.length; ++i) {
                var deviceInfo = deviceInfos[i];
                var option = document.createElement('option');
                option.value = deviceInfo.deviceId;
               if (deviceInfo.kind === 'videoinput') {
                    option.text = deviceInfo.label || 'camera ' +
                        (videoSelect.length + 1);
                    videoSelect.appendChild(option);
                } else {
                    console.log('Found ome other kind of source/device: ', deviceInfo);
                }
            }
        }


        function getStream() {
            if (window.stream) {
                window.stream.getTracks().forEach(function (track) {
                    track.stop();
                });
            }


            var constraints = {
                
                video: {
                    optional: [{
                        sourceId: videoSelect.value
                    }]
                }
            };


            navigator.mediaDevices.getUserMedia(constraints).
                then(gotStream).catch(handleError);
        }


        function gotStream(stream) {
            window.stream = stream; // make stream available to console
            videoElement.srcObject = stream;
        }


        function handleError(error) {
            console.log('Error: ', error);
        }


        //######################## End Video Source #################




        // Get access to the camera!
        if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
            navigator.mediaDevices.getUserMedia({ video: true }).then(function (stream) {
                videoElement.src = window.URL.createObjectURL(stream);
                videoElement.play();


            });
        }
        else {
            document.getElementById("pnlVideo1").style.display = "none";
        }




      




         Trigger photo take
        document.getElementById("snap").addEventListener("click", function () {
            contextPreview.drawImage(videoElement, 0, 0, 300, 224);
            contextUpload.drawImage(videoElement, 0, 0, 300, 224);
            document.getElementById("video").style.display = "none";
            document.getElementById("snap").style.display = "none";
            document.getElementById("canvasPreview").style.display = "block";


            var image = document.getElementById("canvasUpload").toDataURL("image/jpeg");
            image = image.replace('data:image/jpeg;base64,', '');
            $("#imgNric1").val(image);
        });


         Trigger photo take




        document.getElementById("btnOpen1").addEventListener("click", function () {
            document.getElementById("vdoOne").style.display = "block";
            document.getElementById("video").style.display = "block";
            document.getElementById("snap").style.display = "block";
            document.getElementById("canvasPreview").style.display = "none";
        });




</script>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.esbu.nec.bme">


    <uses-permission android:name="android.permission.INTERNET" />


    <!-- To auto-complete the email text field in the login form with the user's emails -->
    <uses-permission android:name="android.permission.GET_ACCOUNTS" />
    <uses-permission android:name="android.permission.READ_PROFILE" />
    <uses-permission android:name="android.permission.READ_CONTACTS" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.VIBRATE" />




    <uses-feature
        android:name="android.hardware.camera"
        android:required="true" />


    <application
        android:allowBackup="true"
        android:icon="@mipmap/sgh"
        android:label="@string/app_name"
        android:supportsRtl="true"


        android:hardwareAccelerated="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />


                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".LoginActivity"
            android:label="@string/title_activity_login"></activity>
    </application>


</manifest>

...
 mWebView = (AdvancedWebView) findViewById(R.id.webview);
        WebSettings webSettings = mWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setBuiltInZoomControls(true);
        webSettings.setAllowFileAccess(true);
...