flutter 如何显示一个底部dialog

一、flutter没有底部dialog之说，但是有一个bottomsheet,flutter和安卓ios最大的不同是，它是在移动系统已经发展非常成熟的时候出现的，所以大多数的功能，比如UI，集成得非常好

void _modalBottomSheetMenu(){
        showModalBottomSheet(
            context: context,
            builder: (builder){
              return new Container(
                height: 350.0,
                color: Colors.transparent, //could change this to Color(0xFF737373), 
                           //so you don't have to change MaterialApp canvasColor
                child: new Container(
                    decoration: new BoxDecoration(
                        color: Colors.white,
                        borderRadius: new BorderRadius.only(
                            topLeft: const Radius.circular(10.0),
                            topRight: const Radius.circular(10.0))),
                    child: new Center(
                      child: new Text("This is a modal sheet"),
                    )),
              );
            }
        );
      }

二、

floatingActionButton: new FloatingActionButton(
        onPressed: () {
          showModalBottomSheet(
              context: context,
              builder: (BuildContext context){
                return new Column(
                  mainAxisSize: MainAxisSize.min,
                  children: <Widget>[
                    new ListTile(
                      leading: new Icon(Icons.photo_camera),
                      title: new Text("Camera"),
                      onTap: () async {
                        imageFile = await ImagePicker.pickImage(source: ImageSource.camera);
                        Navigator.pop(context);
                      },
                    ),
                    new ListTile(
                      leading: new Icon(Icons.photo_library),
                      title: new Text("Gallery"),
                      onTap: () async {
                        imageFile = await ImagePicker.pickImage(source: ImageSource.gallery);
                        Navigator.pop(context);
                      },
                    ),
                  ],
                );
              }
          );
        },
        foregroundColor: Colors.white,
        child: Text('点我'),
      ),