try 使用具有Filter属性的BackdropFilter.希望你得到解决方案！
Get.dialog(
BackdropFilter(
filter: ImageFilter.blur(sigmaX: 10, sigmaY: 10),
child: AlertDialog(
contentPadding: EdgeInsets.zero,
backgroundColor: Colors.transparent,
elevation: 10.0,
content: Container(
height: height,
width: 100.0.w,
decoration: BoxDecoration(
color: Theme.of(context).scaffoldBackgroundColor,
borderRadius: BorderRadius.circular(16),
),
child: Text('Downloading')
),
),
);
);