如何在 flutter 中禁用下拉菜单

Question

How to completely disable dropdown so user can not get to list of dropdown and also change color to grey

DropdownButtonFormField<String>(
      value: selected,
      items: ["Value1", "Value2", "Value3"]
          .map(
            (label) => DropdownMenuItem(
              child: Text(label),
              value: label,
            ),
          )
          .toList(),
      onChanged: (value) {
        setState(() => selected = value);
      },
    )

I tired to set onChange to null but the whole dropdown just disappeared

Answer 1

The only way is to set onChange to null and set disabledHint

DropdownButtonFormField<String>(
      style: TextStyle(color: Colors.grey),
      value: selected,
      disabledHint: Text(selected),  //<-set this one
      items: ["Value1", "Value2", "Value3"]
          .map(
            (label) => DropdownMenuItem(
              child: Text(label),
              value: label,
            ),
          )
          .toList(),
      onChanged: null,
//          (value) {
//          setState(() => selected = value);
//        },
    )