title: Error:RenderBox was not laid out: NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
body: <p>i am having problem using <code>SingleChildScrollView</code> in this way, i dont no what is wrong, i keep getting this error.</p>
  <p>If add the SingleChildScrollView the page will be blank(will not show all the widget)but if i remove the SingleChildScrollView, the page will show.</p>
  <blockquote>
  <p>RenderBox was not laid out: RenderPadding#583c0 relayoutBoundary=up1
  NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
  'package:flutter/src/rendering/box.dart': Failed assertion: line 1929
  pos 12: 'hasSize</p>
  <p>The relevant error-causing widget was Scaffold
  Scaffold:file:///Users/mac/Documents/Uneleap-Platform-master/lib/screens/Pages/forum/forum.dart:25:12</p>
  </blockquote>
  <p>here is the code</p>
  <pre><code>SafeArea(
                  minimum: EdgeInsets.only(left: 25.0, right: 20.0, top: 10.0),
                  child: SingleChildScrollView(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        WidgetForum(
                          details: 'The Get Is Not Geting together ?',
                          name: 'Nina Simon',
                          url: 'assets/dashboard_pic.png',
                        ),
                        SizedBox(
                          height: 5,
                        ),
                        WidgetForum(
                          details:
                              '''Notes is designed for whatever’s on your mind.\nJot down your thoughts. Download Notes.\nThere is something wonderful in writing. \nThe Get Is Not Getting Together?''',
                          name: 'James Nugar',
                          url: 'assets/dashboard_pic.png',
                        ),
                        Text(
                          'Topics',
                          style: TextStyle(
                            fontSize: 35,
                          ),
                        ),
                        Expanded(
                          child: ListView.separated(
                              scrollDirection: Axis.horizontal,
                              separatorBuilder: (_, inedex) =&gt; SizedBox(
                                    width: 20,
                                  ),
                              itemCount: topics.length,
                              itemBuilder: (context, index) {
                                return Container(
                                  height: 50,
                                  width: 100,
                                  decoration: BoxDecoration(
                                    color: Colors.red,
                                    borderRadius: BorderRadius.circular(15),
                                    image: DecorationImage(
                                      image: AssetImage('assets/saved_2.png'),
                                      fit: BoxFit.fill,
                                    ),
                                  ),
                                  child: Column(
                                    children: [
                                      Padding(
                                        padding: const EdgeInsets.all(8.0),
                                        child: Align(
                                          alignment: Alignment.bottomLeft,
                                          child: Text(
                                            topics[index].schoolNmae!,
                                            style: TextStyle(
                                                color: Colors.white,
                                                fontWeight: FontWeight.bold),
                                          ),
                                        ),
                                      )
                                    ],
                                  ),
                                );
                              }),
                        ),
                        WidgetForum(
                          details:
                              '''Notes is designed for whatever’s on your mind.\nJot down your thoughts. Download Notes.\nThere is something wonderful in writing. \nThe Get Is Not Getting Together?''',
                          name: 'Sam Ajayi',
                          url: 'assets/dashboard_pic.png',
                        ),
                      ],
                    ),
                  ),
                ),
                // bottomSheet:
                floatingActionButton: FloatingActionButton(
                  onPressed: () {
                    Scaffold.of(context).showBottomSheet&lt;void&gt;((BuildContext context) {
                      return Container(
                        height: 250,
                        decoration: BoxDecoration(
                          color: Colors.black,
                          borderRadius: BorderRadius.only(
                            topLeft: Radius.circular(10),
                          ),
                        ),
                        child: Padding(
                          padding: const EdgeInsets.symmetric(
                            vertical: 50,
                            horizontal: 15.0,
                          ),
                          child: Column(
                            children: [
                              Row(
                                children: [
                                  Icon(
                                    CustomIcons.answers_forum,
                                    color: Colors.grey,
                                  ),
                                  SizedBox(
                                    width: 10,
                                  ),
                                  Text(
                                    'Post',
                                    style: TextStyle(
                                      fontSize: 25,
                                      fontWeight: FontWeight.bold,
                                      color: Colors.white,
                                    ),
                                  )
                                ],
                              ),
                              Padding(
                                padding: const EdgeInsets.only(right: 120.0),
                                child: Divider(
                                  thickness: 2,
                                  color: Colors.white,
                                ),
                              ),
                              Row(
                                children: [
                                  Icon(
                                    CustomIcons.create_forum,
                                    color: Colors.grey,
                                  ),
                                  SizedBox(
                                    width: 10,
                                  ),
                                  Text(
                                    'Create Forum',
                                    style: TextStyle(
                                      fontSize: 25,
                                      fontWeight: FontWeight.bold,
                                      color: Colors.white,
                                    ),
                                  )
                                ],
                              ),
                              Align(
                                alignment: Alignment.bottomRight,
                                child: GestureDetector(
                                  onTap: () {
                                    Navigator.pop(context);
                                  },
                                  child: Container(
                                    height: 70,
                                    width: 70,
                                    decoration: BoxDecoration(
                                      shape: BoxShape.circle,
                                      color: Colors.white,
                                    ),
                                    child: Center(
                                      child: Icon(Icons.add),
                                    ),
                                  ),
                                ),
                              )
                            ],
                          ),
                        ),
                      );
                    });
                  },
                  child: Icon(Icons.add),
                ),
              );
            }
          }
          
          class WidgetForum extends StatefulWidget {
            final String? name;
            final String? details;
            final String? url;
          
            WidgetForum(
                {Key? key, required this.name, required this.details, required this.url})
                : super(key: key);
          
            @override
            _WidgetForumState createState() =&gt; _WidgetForumState();
          }
          
          class _WidgetForumState extends State&lt;WidgetForum&gt; {
            @override
            Widget build(BuildContext context) {
              return Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Row(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: [
                      Row(
                        children: [
                          Container(
                            height: 50,
                            width: 50,
                            decoration: BoxDecoration(
                              image: DecorationImage(
                                image: AssetImage(widget.url!),
                                fit: BoxFit.fill,
                              ),
                            ),
                          ),
                          SizedBox(
                            width: 5,
                          ),
                          Text(
                            widget.name!,
                            style: TextStyle(fontWeight: FontWeight.bold, fontSize: 25),
                          )
                        ],
                      ),
                      PopupMenuButton(
                        color: Colors.black,
                        offset: Offset(0, 40),
                        itemBuilder: (_) =&gt; &lt;PopupMenuItem&lt;String&gt;&gt;[
                          new PopupMenuItem&lt;String&gt;(
                            child: Center(
                              child: Text(
                                'Fellow',
                                style: TextStyle(
                                  color: Colors.white,
                                ),
                              ),
                            ),
                          ),
                          new PopupMenuItem&lt;String&gt;(
                            child: Center(
                              child: Text(
                                'Block',
                                style: TextStyle(
                                  color: Colors.white,
                                ),
                              ),
                            ),
                          ),
                          new PopupMenuItem&lt;String&gt;(
                            child: Center(
                              child: Text(
                                'Report',
                                style: TextStyle(
                                  color: Colors.white,
                                ),
                              ),
                            ),
                          ),
                        ],
                        child: Container(
                          height: 20,
                          width: 20,
                          child: SvgPicture.asset('assets/library_pre.svg'),
                        ),
                      ),
                    ],
                  ),
                  SizedBox(height: 18),
                  Text(
                    widget.details!,
                    style: TextStyle(fontSize: 15),
                  ),
                  SizedBox(height: 18),
                  Row(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: [
                      Row(
                        children: [
                          Icon(
                            CustomIcons.icons8_up_2_11,
                            color: Colors.red,
                          ),
                          Text('36'),
                          Icon(
                            CustomIcons.icons8_down,
                            color: Colors.grey,
                          ),
                          Icon(
                            CustomIcons.answers_forum,
                            color: Colors.grey,
                          ),
                          Text('3')
                        ],
                      ),
                      Text('Sep 2, 2020')
                    ],
                  ),
                  Divider(
                    thickness: 1,
                  )
                ],
              );
            }
          }
  </code></pre>