StatefulWidget-FLutter

Question

我需要编辑此代码，以仅定义一个可变小部件的方式，该可变小部件能够在每种状态下更改为不同的小部件类型。无论问题和问题的类型是什么，我都必须能够制作动态表格，我处理表格的方式有些复杂且效率不高。因此，关于在每个setState（）上如何为不同的小部件更改相同的变量，是否有任何想法？

    `Column(
                  children: <Widget>[
                    questionText,
                    textCounter > 0 ? textField : SizedBox(),
                    selectCounter > 0 ? selectField : SizedBox()
                  ],
                )),`FutureBuilder(
              future: fetchQuestions(),
              builder: (context, snapshot) {
                if (snapshot.hasData) {
                  for (var i = 0; i < snapshot.data.length; i++) {
                    var temp = snapshot.data[i]['question_value'].toString();
                    var type = snapshot.data[i]['question_type'].toString();
                    questionsList.add(temp);
                    typeList.add(type);
                  }

                  return Align(
                    alignment: Alignment.bottomRight,
                    child: RaisedButton(
                      onPressed: () {
                        changeQuest(questionsList, typeList,
                            snapshot.data.length, snapshot.data);
                      },
                      child: Text('next'),
                    ),
                  );
                } else
                  return Center(child: CircularProgressIndicator());
              },
            ),

    changeQuest(List questions, List type, length, data) {
    setState(() {
      textCounter = 0;
      selectCounter = 0;
      integerCounter = 0;
      if (counter < length) {
        questionText = Text(questions[counter]);
        if (type[counter] == 'Integer') {
          textCounter++;
          textField = TextFormField(
            decoration: new InputDecoration(labelText: "Enter your number"),
            keyboardType: TextInputType.number,
            inputFormatters: <TextInputFormatter>[
              WhitelistingTextInputFormatter.digitsOnly
            ], // Only numbers can be entered
          );
        } else if (type[counter] == 'Text') {
          textCounter++;
          textField = TextFormField(
            decoration: new InputDecoration(labelText: "Enter a text"),
            keyboardType: TextInputType.text,
          );
        } else if (type[counter] == 'Select') {
          selectCounter++;
          for (var i = 0; i < data[counter]['answers'].length; i++) {
            answersList
                .add(data[counter]['answers'][i]['answer_value'].toString());
          }
          dropDownValue = answersList[0];
          selectField = DropdownButton<String>(
            value: dropDownValue,
            icon: Icon(Icons.arrow_downward),
            iconSize: 24,
            elevation: 16,
            style: TextStyle(color: Colors.deepPurple),
            underline: Container(
              height: 2,
              color: Colors.deepPurpleAccent,
            ),
            onChanged: (value) {
              setState(() {
               dropDownValue = value;
              });
            },
            items: answersList
                .map<DropdownMenuItem<String>>((String value) {
              return DropdownMenuItem<String>(
                value: value,
                child: Text(value),
              );
            }).toList(),
          );
          print (dropDownValue);
        }
      }

      counter++;
    });
  }
    

我需要编辑此代码，以仅定义一个可变小部件的方式，该可变小部件能够在每种状态下更改为不同的小部件类型。无论什么...

Answer 1

正如@proversion在评论中所说，如果条件返回true或false，您可以在小部件树中检入。