试试这个
1.添加对AndroidManifest.xml的权限

<uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

2.MainActivity.java

public class MainActivity extends AppCompatActivity {
public ProgressDialog progressDialog;
private WebView webView;

private static final int FILECHOOSER_RESULTCODE = 1;
private ValueCallback<Uri> mUploadMessage;
private Uri mCapturedImageURI = null;
private String mCameraPhotoPath;
// the same for Android 5.0 methods only
private ValueCallback<Uri[]> mFilePathCallback;

/* access modifiers changed from: protected */
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView((int) R.layout.activity_main);
    ProgressDialog progressDialog2 = new ProgressDialog(this);
    this.progressDialog = progressDialog2;
    progressDialog2.setMessage("Please wait ...");
    this.progressDialog.setCancelable(false);
    this.progressDialog.show();
    load();
}

private void load() {
    WebView webView2 = (WebView) findViewById(R.id.web_view);
    this.webView = webView2;
    webView2.loadUrl("https://google.com/");
    this.webView.getSettings().setDomStorageEnabled(true);
    this.webView.getSettings().setJavaScriptEnabled(true);
    this.webView.getSettings().setSaveFormData(true);
    this.webView.getSettings().setAllowContentAccess(true);
    this.webView.getSettings().setAllowFileAccess(true);
    this.webView.getSettings().setAllowFileAccessFromFileURLs(true);
    this.webView.getSettings().setAllowUniversalAccessFromFileURLs(true);
    this.webView.getSettings().setAllowFileAccess(true);
    this.webView.getSettings().setSupportZoom(true);
    this.webView.getSettings().setBuiltInZoomControls(true);
    this.webView.getSettings().setDisplayZoomControls(false);

    this.webView.setClickable(true);

    this.webView.setWebChromeClient(new WebChromeClient() {
        private View mCustomView;
        private WebChromeClient.CustomViewCallback mCustomViewCallback;
        protected FrameLayout mFullscreenContainer;
        private int mOriginalOrientation;
        private int mOriginalSystemUiVisibility;

        public Bitmap getDefaultVideoPoster()
        {
            if (mCustomView == null) {
                return null;
            }
            return BitmapFactory.decodeResource(getApplicationContext().getResources(), 2130837573);
        }

        public void onHideCustomView()
        {
            ((FrameLayout)getWindow().getDecorView()).removeView(this.mCustomView);
            this.mCustomView = null;
            getWindow().getDecorView().setSystemUiVisibility(this.mOriginalSystemUiVisibility);
            setRequestedOrientation(this.mOriginalOrientation);
            this.mCustomViewCallback.onCustomViewHidden();
            this.mCustomViewCallback = null;
        }

        public void onShowCustomView(View paramView, WebChromeClient.CustomViewCallback paramCustomViewCallback)
        {
            if (this.mCustomView != null)
            {
                onHideCustomView();
                return;
            }
            this.mCustomView = paramView;
            this.mOriginalSystemUiVisibility = getWindow().getDecorView().getSystemUiVisibility();
            this.mOriginalOrientation = getRequestedOrientation();
            this.mCustomViewCallback = paramCustomViewCallback;
            ((FrameLayout)getWindow().getDecorView()).addView(this.mCustomView, new FrameLayout.LayoutParams(-1, -1));
            getWindow().getDecorView().setSystemUiVisibility(3846 | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
        }

        public boolean onShowFileChooser(
                WebView webView, ValueCallback<Uri[]> filePathCallback,
                WebChromeClient.FileChooserParams fileChooserParams) {
            if (mFilePathCallback != null) {
                mFilePathCallback.onReceiveValue(null);
            }
            mFilePathCallback = filePathCallback;

            Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            if (takePictureIntent.resolveActivity(getPackageManager()) != null) {

                // create the file where the photo should go
                File photoFile = null;
                try {
                    photoFile = createImageFile();
                    takePictureIntent.putExtra("PhotoPath", mCameraPhotoPath);
                } catch (IOException ex) {
                    // Error occurred while creating the File
                    Log.e("Adi", "Unable to create Image File", ex);
                }

                // continue only if the file was successfully created
                if (photoFile != null) {
                    mCameraPhotoPath = "file:" + photoFile.getAbsolutePath();
                    takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
                            Uri.fromFile(photoFile));
                } else {
                    takePictureIntent = null;
                }
            }

            Intent contentSelectionIntent = new Intent(Intent.ACTION_GET_CONTENT);
            contentSelectionIntent.addCategory(Intent.CATEGORY_OPENABLE);
            contentSelectionIntent.setType("image/*");

            Intent[] intentArray;
            if (takePictureIntent != null) {
                intentArray = new Intent[]{takePictureIntent};
            } else {
                intentArray = new Intent[0];
            }

            Intent chooserIntent = new Intent(Intent.ACTION_CHOOSER);
            chooserIntent.putExtra(Intent.EXTRA_INTENT, contentSelectionIntent);
            chooserIntent.putExtra(Intent.EXTRA_TITLE, "Select image/video");
            chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentArray);

            startActivityForResult(chooserIntent, FILECHOOSER_RESULTCODE);

            return true;
        }

        // creating image files (Lollipop only)
        private File createImageFile() throws IOException {

            File imageStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "DirectoryNameHere");

            if (!imageStorageDir.exists()) {
                imageStorageDir.mkdirs();
            }

            // create an image file name
            imageStorageDir = new File(imageStorageDir + File.separator + "IMG_" + String.valueOf(System.currentTimeMillis()) + ".jpg");
            return imageStorageDir;
        }

        // openFileChooser for Android 3.0+
        public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType) {
            mUploadMessage = uploadMsg;

            try {
                File imageStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "DirectoryNameHere");

                if (!imageStorageDir.exists()) {
                    imageStorageDir.mkdirs();
                }

                File file = new File(imageStorageDir + File.separator + "IMG_" + String.valueOf(System.currentTimeMillis()) + ".jpg");

                mCapturedImageURI = Uri.fromFile(file); // save to the private variable

                final Intent captureIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
                captureIntent.putExtra(MediaStore.EXTRA_OUTPUT, mCapturedImageURI);
                // captureIntent.putExtra(MediaStore.EXTRA_SCREEN_ORIENTATION, ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

                Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                i.addCategory(Intent.CATEGORY_OPENABLE);
                i.setType("image/*");

                Intent chooserIntent = Intent.createChooser(i, "Select image/video");
                chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, new Parcelable[]{captureIntent});

                startActivityForResult(chooserIntent, FILECHOOSER_RESULTCODE);
            } catch (Exception e) {
                Toast.makeText(getBaseContext(), "Camera Exception:" + e, Toast.LENGTH_LONG).show();
            }

        }

        // openFileChooser for Android < 3.0
        public void openFileChooser(ValueCallback<Uri> uploadMsg) {
            openFileChooser(uploadMsg, "");
        }

        // openFileChooser for other Android versions
        /* may not work on KitKat due to lack of implementation of openFileChooser() or onShowFileChooser()
           https://code.google.com/p/android/issues/detail?id=62220
           however newer versions of KitKat fixed it on some devices */
        public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
            openFileChooser(uploadMsg, acceptType);
        }
    });

    webView.setWebViewClient(new WebViewClient() {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);
            progressDialog.dismiss();
        }
    });
}

// return here when file selected from camera or from SD Card
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {

    // code for all versions except of Lollipop
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {

        if (requestCode == FILECHOOSER_RESULTCODE) {
            if (null == this.mUploadMessage) {
                return;
            }

            Uri result = null;

            try {
                if (resultCode != RESULT_OK) {
                    result = null;
                } else {
                    // retrieve from the private variable if the intent is null
                    result = data == null ? mCapturedImageURI : data.getData();
                }
            } catch (Exception e) {
                Toast.makeText(getApplicationContext(), "activity :" + e, Toast.LENGTH_LONG).show();
            }

            mUploadMessage.onReceiveValue(result);
            mUploadMessage = null;
        }

    } // end of code for all versions except of Lollipop

    // start of code for Lollipop only
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {

        if (requestCode != FILECHOOSER_RESULTCODE || mFilePathCallback == null) {
            super.onActivityResult(requestCode, resultCode, data);
            return;
        }

        Uri[] results = null;

        // check that the response is a good one
        if (resultCode == Activity.RESULT_OK) {
            if (data == null || data.getData() == null) {
                // if there is not data, then we may have taken a photo
                if (mCameraPhotoPath != null) {
                    results = new Uri[]{Uri.parse(mCameraPhotoPath)};
                }
            } else {
                String dataString = data.getDataString();
                if (dataString != null) {
                    results = new Uri[]{Uri.parse(dataString)};
                }
            }
        }

        mFilePathCallback.onReceiveValue(results);
        mFilePathCallback = null;

    } // end of code for Lollipop only
}

}