flutter - 如何省略第二个条件

Question

如何在条件语句中省略第二个条件？

    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        message != null
            ? Padding(
                padding: const EdgeInsets.all(24.0),
                child: Text(message),
              )
            : null, // how to omit second condition?
      ],
    );

当第二个条件为空我得到

════════ Exception caught by widgets library ════════ The following assertion was thrown building ExportData(dirty, state: _ExportDataState#e723d): Column's children must not contain any null values, but a null value was found at index 4

Answer 1

我更喜欢SizedBox而不是Container。

return Column(
  mainAxisAlignment: MainAxisAlignment.center,
  children: <Widget>[
    message != null
        ? Padding(
            padding: const EdgeInsets.all(24.0),
            child: Text(message),
          )
        : SizedBox(),
  ],
);