UI for meme generator app

ui_meme_generator_flutter.dart

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SingleChildScrollView(
        child: Container(
          child: Column(
            children: <Widget>[
              SizedBox(
                height: 50,
              ),
              Image.asset(
                "assets/memegenrator.png",
                height: 70,
              ),
              SizedBox(
                height: 14,
              ),
              RepaintBoundary(
                key: globalKey,
                child: Stack(
                  children: <Widget>[
                    _image != null
                        ? Image.file(
                            _image,
                            height: 300,
                            fit: BoxFit.fitHeight,
                          )
                        : Container(),
                    Container(
                      width: MediaQuery.of(context).size.width,
                      height: 300,
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: <Widget>[
                          Container(
                            padding: EdgeInsets.symmetric(vertical: 8),
                            child: Text(
                              headerText.toUpperCase(),
                              textAlign: TextAlign.center,
                              style: TextStyle(
                                  color: Colors.white,
                                  fontWeight: FontWeight.w700,
                                  fontSize: 26,
                                shadows: <Shadow>[
                                  Shadow(
                                    offset: Offset(2.0, 2.0),
                                    blurRadius: 3.0,
                                    color: Colors.black87,
                                  ),
                                  Shadow(
                                    offset: Offset(2.0, 2.0),
                                    blurRadius: 8.0,
                                    color: Colors.black87,
                                  ),
                                ],),

                            ),
                          ),
                          Spacer(),
                          Container(
                              padding: EdgeInsets.symmetric(vertical: 8),
                              child: Text(
                                footerText.toUpperCase(),
                                textAlign: TextAlign.center,
                                style: TextStyle(
                                    color: Colors.white,
                                    fontWeight: FontWeight.w700,
                                    fontSize: 26,
                                  shadows: <Shadow>[
                                    Shadow(
                                      offset: Offset(2.0, 2.0),
                                      blurRadius: 3.0,
                                      color: Colors.black87,
                                    ),
                                    Shadow(
                                      offset: Offset(2.0, 2.0),
                                      blurRadius: 8.0,
                                      color: Colors.black87,
                                    ),
                                  ],),
                              ))
                        ],
                      ),
                    ),
                  ],
                ),
              ),
              SizedBox(
                height: 20,
              ),
              imageSelected
                  ? Container(
                padding: EdgeInsets.symmetric(horizontal: 20),
                    child: Column(
                        children: <Widget>[
                          TextField(
                            onChanged: (val) {
                              setState(() {
                                headerText = val;
                              });
                            },
                            decoration: InputDecoration(hintText: "Header Text"),
                          ),
                          SizedBox(
                            height: 12,
                          ),
                          TextField(
                            onChanged: (val) {
                              setState(() {
                                footerText = val;
                              });
                            },
                            decoration: InputDecoration(hintText: "Footer Text"),
                          ),
                          SizedBox(height: 20,),
                          RaisedButton(
                            onPressed: () {
                              //TODO
                              takeScreenshot();
                            },
                            child: Text("Save"),
                          )
                        ],
                      ),
                  )
                  : Container(
                      child: Center(
                        child: Text("Select image to get started"),
                      ),
                    ),
              _imageFile != null ? Image.file(_imageFile) : Container(),
            ],
          ),
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          getImage();
        },
        child: Icon(Icons.add_a_photo),
      ),
    );
  }