如何获取flutter中gridview项目占用的高度和宽度

GridView的子元素大小取决于childAspectRatio.如果您希望为itemBuilder提供不同的大小，则需要使用另一个小部件进行包装，该小部件将用于处理父约束.

class TestGrid extends StatelessWidget {
  const TestGrid({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: LayoutBuilder(
        builder: (BuildContext context, BoxConstraints constraints) {
          final currentViewWidth = constraints.maxWidth;
          final currentViewHeight = constraints.maxHeight;
          bool isLargeScreen = currentViewWidth > 1200;
          return GridView.builder(
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              mainAxisSpacing: 16,
              crossAxisSpacing: 8,
              childAspectRatio: isLargeScreen ? 1.5 : 1.2, //handle the child size
              crossAxisCount: isLargeScreen ? 4 : 2,
            ),
            itemBuilder: (context, index) {
              return LayoutBuilder(
                builder: (BuildContext context, BoxConstraints constraints) {
                  final width = constraints.maxWidth;
                  final height = constraints.maxHeight;
                  return Center(
                    //this will take the constraints of GridView.builder, which is comes from `childAspectRatio`
                    child: Container(
                      alignment: Alignment.center,
                      decoration: BoxDecoration(
                        color: Colors.grey,
                        borderRadius: BorderRadius.circular(10),
                      ),
                      child: ColoredBox(color: index.isEven ? Colors.red : Colors.blue, child: Text("$width x $height")),
                    ),
                  );
                },
              );
            },
          );
        },
      ),
    );
  }
}