只要 textField 中有一些文本，我希望箭头图标出现，否则它应该消失。 如果我使用 TextField 而不是 AutoCompleteTextField，它工作正常。另外，如果我删除 suffixIcon 处的条件，即使那样它也能正常工作。 请参阅下面的代码。

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  bool arrow = false;
  var controller = TextEditingController();

  @override
  void initState() {
    super.initState();
    controller.addListener(() {
      print(controller.text);
      setState(() {
        controller.text == '' ? arrow = false : arrow = true;
      });
    });
  }

  Widget suffixIcon() {
    var iconButton = IconButton(
        icon: Icon(Icons.arrow_forward),
        onPressed: () {},
        color: Theme.of(context).primaryColor);

    return arrow ? iconButton : null;
    // return iconButton;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            AutoCompleteTextField(
              controller: controller,
              decoration: InputDecoration(
                suffixIcon: suffixIcon(),
              ),
              itemSorter: (a, b) {},
              suggestions: [],
              itemSubmitted: (data) {},
              itemFilter: (suggestion, String query) {},
              itemBuilder: (BuildContext context, suggestion) {},
              key: null,
            ),
          ],
        ),
      ),
    );
  }
}

最佳答案

suffixIcon: Controller.text.length > 0 ? InkWell(
                            child: Icon(Icons.arrow_forward, color: Colors.grey,),
                            onTap: (){
                              setState(() {
                                Controller.clear();
                              });
                            },
                          ) : SizedBox()

https://stackoverflow.com/questions/65171117/