title: Update the variable depending on what data was returned from the previous screen in Flutter using the Navigator
body: <p>I have a variable _PhotoName, this variable is null, but when I take a photo and repeat the term base64 from another screen, I would like the variable _PhotoNameto be a timestamp.img , if base64 is not null.
  here is the part of the code that displays this variable, and there is also code where base 64 is returned:</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>              Container(
                padding: EdgeInsets.only(left: 15, right: 15, top: 5),
                color: Colors.white,
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: &lt;Widget&gt;[
                    Expanded(
                      child: Text(
                          "$_PhotoName",
                          style: TextStyle(color: Colors.black, fontSize: 15)
  
                      ),
  
                    ),
                    Expanded(
                      child: ButtonTheme(
                          alignedDropdown: true,
                          child: new RaisedButton.icon(
                            label: Text('Add Image'),//Добавити фото
                            onPressed: () async{
                              _imageB64 = await  Navigator.push(
                                  context,
                                  MaterialPageRoute(
                                  builder: (context) =&gt; image.PicturePreview(camera)),
                               );
  
                            },
  
                            icon : Icon(Icons.camera_alt),
                          )
                      ),
                    ),
  
                  ],
  
                ),
              ),</code></pre>
  </div>
  </div>
  </p>