android native and javascript communication in browsing a file from device

Question

I have opened html page in webview. Now on click of any button in the webview, I want user to pick an image from gallery and show that image in webview.

Code in onCreate() method:

       myBrowser = (WebView)findViewById(R.id.webView1);

       final MyJavaScriptInterface myJavaScriptInterface
        = new MyJavaScriptInterface(this);
       myBrowser.addJavascriptInterface(myJavaScriptInterface, "AndroidFunction");

       myBrowser.getSettings().setJavaScriptEnabled(true); 
       myBrowser.loadUrl("file:///android_asset/mypage.html");

Added javascriptInterface:

   public class MyJavaScriptInterface {
      Context mContext;

         MyJavaScriptInterface(Context c) {
             mContext = c;
         }


         public void pickImageFromGallery()
        {
            Intent i = new Intent(
                     Intent.ACTION_PICK,
                     android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

             startActivityForResult(i, RESULT_LOAD_IMAGE);
        }

     }

onActivityResult() method:

       @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
            Uri selectedImage = data.getData();
            String[] filePathColumn = { MediaStore.Images.Media.DATA };

            Cursor cursor = getContentResolver().query(selectedImage,
                    filePathColumn, null, null, null);
            cursor.moveToFirst();

            int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
            String picturePath = cursor.getString(columnIndex);
            cursor.close();

            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = 4;
            Bitmap image = BitmapFactory.decodeFile(picturePath, o2);


        }


    }

Now whenever I will click on the button in webview, it open the gallery and let the user to select an image from the gallery. But how can I send that image path again to the javascript, so that It can show that image in webview?