title: How to scroll a page, with image and gridView in flutter
body: <p>My code for the page is like this. I need to scroll part below app bar.</p>
  <pre><code>return Scaffold(
    backgroundColor: Theme.of(context).accentColor,
    appBar: AppBar(
      backgroundColor: Colors.transparent,
      elevation: 0.0,
      title: Text(campTitle,
        style: TextStyle(color: Theme.of(context).primaryColor,
          
          ),
        ),
    ),
  
    body: Column(children: [
              Padding(
                    padding: const EdgeInsets.only(left: 40, right: 40, top: 10),
                    child: ClipRRect(
                      borderRadius: BorderRadius.circular(28),
                      child: Image.asset('assets/images/Flyer-Kalabrien-2020.jpg',
                        //fit: BoxFit.fill
                        
                      ),
                    ),
                  ),
            
  
                 Expanded(
                   child: GridView(
                            padding: const EdgeInsets.all(25),
                    gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
                      maxCrossAxisExtent: 200,
                      childAspectRatio: 1,
                      crossAxisSpacing: 20,
                      mainAxisSpacing: 0
                      ),
                      children: [
                          CampItems(),
                          CampItems(),
                          CampItems(),
                          CampItems()
  
                        
                        
  
                      ],
                    ),
                 ),
              
        ]
     ), 
    );
  </code></pre>
  <p>I need to make the part below app bar scrollable. first I have an image and then below the image an GridView.I tried SingleChildScrollView and other widgets but then I only see a white screen and the error is:</p>
  <pre><code>_AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:46:39)
  #1      _AssertionError._throwNew (dart:core-patch/errors_patch.dart:36:5)
  #2      RenderBox.size (package:flutter/src/rendering/box.dart:1785:12)
  #3      RenderProxyBoxWithHitTestBehavior.hitTest (package:flutter/src/rendering/proxy_box.dart:168:9)
  #4      RenderBoxContainerDefaultsMixin.defaultHitTestChildren.&lt;anonymous closure&gt; (package:flutter/src/rendering/box.dart:2596:25)
  #5      BoxHitTestResult.addWithPaintOffset (package:flutter/src/rendering/box.dart:787:31)
  #6      RenderBoxContainerDefaultsMixin.defaultHitTestChildren (package:flutter/src/rendering/box.dart:2591:33)
  #7      RenderCustomMultiChildLayoutBox.hitTestChildren (package:flutter/src/rendering/custom_layout.dart:412:12)
  #8      Rend&lt;…&gt;
  </code></pre>