anchor.diff:      });
     }
   
  -
     @override
     Widget build(BuildContext context) {
       return Scaffold(
  
positive.code:   TextEditingController weightController = TextEditingController();
    TextEditingController heightController = TextEditingController();
  
    String _infoText = "Informe seus dados!";
  
    void _resetFields(){
      weightController.text = "";
      heightController.text = "";
      _infoText = "Informe seus dados!";
    }
  
  
    void calculate(){
      setState(() {
        double weight = double.parse(weightController.text);
        double height = double.parse(heightController.text) / 100;
  
negative.code:             onPressed: _resetFields,
            )
          ],
        ),
        backgroundColor: Colors.white,
        body: SingleChildScrollView(
          padding: EdgeInsets.fromLTRB(10.0, 0.0, 10.0, 0.0),
          child: Form(
            key: _formKey,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: <Widget>[
                Icon(Icons.person_outline, size: 120.0, color: Colors.green),
                TextFormField(
                  keyboardType: TextInputType.number,
                  decoration: InputDecoration(
                      labelText: "Peso (kg)",
                      labelStyle: TextStyle(color: Colors.green)),
                  textAlign: TextAlign.center,
                  style: TextStyle(color: Colors.green, fontSize: 25.0),
                  controller: weightController,
                  validator: (value) {
                    if(value.isEmpty){
                      return "Insira seu Peso!";
                    }
                  },
                ),
                TextFormField(
                  keyboardType: TextInputType.number,
                  decoration: InputDecoration(
                      labelText: "Altura (cm)",
                      labelStyle: TextStyle(color: Colors.green)),
                  textAlign: TextAlign.center,
                  style: TextStyle(color: Colors.green, fontSize: 25.0),
                  controller: heightController,
                  validator: (value) {
                    if(value.isEmpty){
                      return "Insira sua Altura!";
                    }
                  },
                ),
                Padding(
                  padding: EdgeInsets.only(top: 10.0, bottom: 10.0),
                  child: Container(
                    height: 50.0,
                    child: RaisedButton(
                      onPressed: () {
                        if(_formKey.currentState.validate()){
                          _calculate();
                        }
                      },
                      child: Text(
                        "Calcular",
                        style: TextStyle(color: Colors.white, fontSize: 25.0),
                      ),
                      color: Colors.green,
                    ),
                  ),
                ),
                Text(
                  _infoText,
                  textAlign: TextAlign.center,
                  style: TextStyle(color: Colors.green, fontSize: 25.0),
                )
              ],
            ),
          ),
        ),
      );
    }
  }
  