Flutter使用FutureBuilder

// 每次构建都会请求并刷新页面
// 有一定局限性：如加载更多等功能叠加不合适使用FutureBuilder
class TestFutureBuilder extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    CYScreenUtils.init(designedWidth: 750);
    return FutureBuilder<List<CategoryModel>>(
      future: CYJsonDecode.getCategory(),//异步请求
      builder: (context,snapshot){
        if (!snapshot.hasData) return Center(child: CircularProgressIndicator());// 数据不存在，加载选型进度条
        if (snapshot.error) return Center(child: Text("请求失败"));// 请求失败
        final data = snapshot.data;
        return GridView.builder(
          padding: EdgeInsets.all(10.px),
          itemCount: data.length,
          gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
            crossAxisCount: 2,// 一排两个
            crossAxisSpacing: 10.px,//间距
            mainAxisSpacing: 10.px,//
            childAspectRatio: 1.5
          ),
          itemBuilder: (context,index){
            return TestItem(data[index]);
          },
        );
      },
    );
  }
}