无法在行 Flutter 下方的卡片内添加列

Cannot add column inside a card below a row Flutter

我正在实现一个有行的卡片,我想在 flutter 中的卡片中的行下方添加列。我无法在卡片底部添加列。

Column buildWorkshopSection() {
    return Column(
      children: [
        Card(
          margin: EdgeInsets.symmetric(horizontal: 20.0, vertical: 5.0),
          clipBehavior: Clip.antiAlias,
          color: Colors.white,
          elevation: 5.0,
          child: Padding(
            padding:
                const EdgeInsets.symmetric(horizontal: 8.0, vertical: 22.0),
            child: Row(
              children: <Widget>[
                Expanded(
                  child: Column(
                    children: <Widget>[
                      SizedBox(
                        height: 5.0,
                      ),
                      buildStartTimeWorkshop(),
                    ],
                  ),
                ),
                Expanded(
                  child: Column(
                    children: <Widget>[
                      SizedBox(
                        height: 5.0,
                      ),
                      buildCloseTimeWorkshop(),
                    ],
                  ),
                ),
              ],
            ),
          ),
        )
      ],
    );
  }

像这样添加提交按钮

Card(
                      margin:
                          EdgeInsets.symmetric(horizontal: 20.0, vertical: 5.0),
                      clipBehavior: Clip.antiAlias,
                      color: Colors.white,
                      elevation: 5.0,
                      child: Padding(
                        padding: const EdgeInsets.symmetric(
                            horizontal: 8.0, vertical: 22.0),
                        child: Column(
                          children: [
                            Row(
                              children: <Widget>[
                                Expanded(
                                  child: Column(
                                    children: <Widget>[
                                      SizedBox(
                                        height: 5.0,
                                      ),
                                      buildStartTimeWorkshop(),
                                    ],
                                  ),
                                ),
                                Expanded(
                                  child: Column(
                                    children: <Widget>[
                                      SizedBox(
                                        height: 5.0,
                                      ),
                                      buildCloseTimeWorkshop(),
                                    ],
                                  ),
                                ),
                              ],
                            ),
                            SizedBox(
                              height: 20,
                            ),
                            RaisedButton(
                              onPressed: () {},
                              child: Text("Submit"),
                            )
                          ],
                        ),
                      ),
                    ),

看起来像这样