flutter - 更改图标颜色或删除它

Question

我有这些容器来选择一些图像。当用户选择图像时，它会覆盖整个容器，所以我希望子项(图标)在选择图像后是透明的。

InkWell(
                          onTap: () async {
                            XFile? image3 = await _picker.pickImage(
                                source: ImageSource.gallery);

                            if (image3 == null) {
                              debugPrint("got null");
                              return;
                            }
                            final image =
                                Image.memory(await image3.readAsBytes());
                            decorationImage3 = DecorationImage(
                              fit: BoxFit.cover,
                              image: image.image,
                            );
                            setState(() {});
                          },
                          child: Container(
                            height: MediaQuery.of(context).size.width / 4 - 25,
                            width: MediaQuery.of(context).size.width / 4 - 25,
                            decoration: BoxDecoration(
                              color: Colors.blue.shade900,
                              borderRadius: BorderRadius.circular(5),
                              image: decorationImage3,
                            ),
                            child: const Icon(Icons.add, color: Colors.white),
                          ),
                        ),

Answer 1

改用这个

child: (image3 == null)?Icon(Icons.add, color: Colors.white):Sizedbox.shrink();