如何在没有主体的情况下获取标签栏索引的值

Question

我遇到一种情况，我只想在底部工作表中显示选项卡，例如whatsapp如何显示以共享实时位置，所以我为此使用了默认选项卡栏，但我想读取用户在没有任何tabBar视图主体的情况下选择的索引。请帮助我。

                             new DefaultTabController(
                                  length: 3,
                                  child: new Column(
                                    mainAxisAlignment: MainAxisAlignment.start,
                                    children: <Widget>[
                                      new Container(
                                        padding: EdgeInsets.only(top: 13.0,bottom: 25.0),
                                        alignment: Alignment.topCenter,
                                        child: new Material(
                                          color: Colors.white,
                                          child: new TabBar(
                                            labelColor: Color(0xFF454f63),
                                            unselectedLabelColor: Color(0XFF959dad),
                                            indicator: BoxDecoration(
                                              gradient: LinearGradient(
                                                begin: Alignment.topLeft,
                                                end: Alignment(0.3, 0.0), // 10% of the width, so there are ten blinds.
                                                colors: [const Color(0xFF0080ff),const Color(0XFF00ff80)], // whitish to gray
                                                tileMode: TileMode.clamp, // repeats the gradient over the canvas
                                              ),
                                            ),
                                            tabs: [
                                              GestureDetector(
                                                onTap: check1(),
                                                child: Tab(
                                                  child : new Text("1 Hour",
                                                    style: new TextStyle(
                                                      fontSize: 13.0,
                                                    )
                                                  ),
                                                ),
                                              ),
                                              GestureDetector(
                                                onTap: check2(),
                                                child: Tab(
                                                  child : new Text("8 Hours",
                                                    style: new TextStyle(
                                                      fontSize: 13.0,
                                                    )
                                                  ),
                                                ),
                                              ),
                                              GestureDetector(
                                                onTap: check3(),
                                                child: Tab(
                                                  child : new Text("1 Day",
                                                    style: new TextStyle(
                                                      fontSize: 13.0,
                                                    )
                                                  ),
                                                ),
                                              ),
                                            ],
                                          ),
                                        ),
                                      ),
                                    ],
                                  ),
                                ),

P.S：