这是我的代码:

@override
Widget build(BuildContext context) {
  return new Material(
    color: Colors.deepPurpleAccent,
    child: new Column(
     mainAxisAlignment: MainAxisAlignment.center,
        children:<Widget>[new GridView.count(crossAxisCount: _column,children: new List.generate(_row*_column, (index) {
          return new Center(
              child: new CellWidget()
          );
        }),)]
    )
  );
}

例外情况如下:

I/flutter ( 9925): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter ( 9925): The following assertion was thrown during performResize():
I/flutter ( 9925): Vertical viewport was given unbounded height.
I/flutter ( 9925): Viewports expand in the scrolling direction to fill their container.In this case, a vertical
I/flutter ( 9925): viewport was given an unlimited amount of vertical space in which to expand. This situation
I/flutter ( 9925): typically happens when a scrollable widget is nested inside another scrollable widget.
I/flutter ( 9925): If this widget is always nested in a scrollable widget there is no need to use a viewport because
I/flutter ( 9925): there will always be enough vertical space for the children. In this case, consider using a Column
I/flutter ( 9925): instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size
I/flutter ( 9925): the height of the viewport to the sum of the heights of its children.
I/flutter ( 9925): 
I/flutter ( 9925): When the exception was thrown, this was the stack:
I/flutter ( 9925): #0      RenderViewport.performResize.<anonymous closure> (package:flutter/src/rendering/viewport.dart:827:15)
I/flutter ( 9925): #1      RenderViewport.performResize (package:flutter/src/rendering/viewport.dart:880:6)
I/flutter ( 9925): #2      RenderObject.layout (package:flutter/src/rendering/object.dart:1555:9)

当前回答

不要使用Column进行单子对齐。使用Align代替。

new Align(
  alignment: Alignment.topCenter,
  child: new GridView(),
)

其他回答

如果你使用CustomScrollView

你可以试试SliverFillRemaining

ListView.builder(
                scrollDirection: Axis.vertical,
                shrinkWrap: true,
                itemCount: 10,
                itemBuilder: (BuildContext context, int index) {
                  return Padding(
                    padding: const EdgeInsets.all(8.0),
                    child: Container(
                      height: 100,
                      width: double.infinity,
                      color: Colors.pinkAccent,

                    ),
                  );
                },
              ),

加上这两行

ListView.builder(
    scrollDirection: Axis.vertical,
    shrinkWrap: true,
...

将网格视图放置在Flexible或Expanded小部件内

return new Material(
    color: Colors.deepPurpleAccent,
    child: new Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children:<Widget>[
         Flexible(
          child:  GridView.count(crossAxisCount: _column,children: new List.generate(_row*_column, (index) {
          return new Center(
             child: new CellWidget(),
          );
        }),))]
    )
);

虽然shrinkWrap可以做到,但你不能在ListView中滚动。

如果你想要滚动功能,你可以添加物理属性:

ListView.builder(
    scrollDirection: Axis.vertical,
    shrinkWrap: true,
    physics: ScrollPhysics(),
...