当键盘在 Flutter TextField 中可见时，键盘顶部有大量空白

这是我的代码：

build(BuildContext context) {
  return new Scaffold(
    body: new SafeArea(
    child: new ListView.builder(
        itemBuilder: (itemBuilder),
      itemCount: (1),
      padding: kMaterialListPadding,
    ),
  )
 );
}
itemBuilder(BuildContext context, int index) {
    return new TextFormField(
        decoration: new InputDecoration(
          border: const OutlineInputBorder(),
          hintText: "What's on your mind?",
          helperText: "5-500 characters",
        ),
        maxLines: 3,
    );
}

When I tap on the text field, keyboard opens but lot of blank space appears on top of keyboard as you can see in the picture (border of textfield is cut).

这是因为 ListView 的原因。如果我只将文本字段添加到正文中，外观就很好。

造成大量空间浪费的原因是因为脚手架里有脚手架。每个脚手架都增加了键盘的空间。去掉一个就解决了问题。