-1

这段代码的作用是在您单击光标时打印光标在文本中的位置。

  TextEditingController controller = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          widget.title,
        ),
      ),
      body: TextField(
        controller: controller,
        keyboardType: TextInputType.multiline,
        maxLines: null,
        onTap: () {
          int pos = controller.selection.start;
          print(
            "Position: $pos",
          );
        },
      ),
    );
  }

但问题是这是针对网络的，所以我需要它在光标移动时说出光标的位置，而不仅仅是在我点击它时。我的意思是如果你用键盘移动光标，它也应该打印位置。

我已经尝试过使用 GestureDetector 和 Focus，但什么也没有。知道我可以使用什么吗？

更新：我找到的解决方案如下，它可以完美地满足我的需要：

TextEditingController controller = TextEditingController();

int cursorPosition = 0;

@override
void initState() {
  controller.addListener(() {
    setState(() {
      cursorPosition = controller.selection.base.offset;
      print("cursorPosition: $cursorPosition");
    });
  });
  super.initState();
}

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(
      title: Text(
        widget.title,
      ),
    ),
    body: TextField(
      controller: controller,
      keyboardType: TextInputType.multiline,
      maxLines: null,
    ),
  );
}

完整代码：

    import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  TextEditingController controller = TextEditingController();

  int cursorPosition = 0;

  @override
  void initState() {
    controller.addListener(() {
      setState(() {
        cursorPosition = controller.selection.base.offset;
        print("cursorPosition: $cursorPosition");
      });
    });
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          widget.title,
        ),
      ),
      body: TextField(
        controller: controller,
        keyboardType: TextInputType.multiline,
        maxLines: null,
      ),
    );
  }
}
4

2 回答 2

0

我找到的解决方案如下，它可以完美地满足我的需要：

TextEditingController controller = TextEditingController();

int cursorPosition = 0;

@override
void initState() {
  controller.addListener(() {
    setState(() {
      cursorPosition = controller.selection.base.offset;
      print("cursorPosition: $cursorPosition");
    });
  });
  super.initState();
}

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(
      title: Text(
        widget.title,
      ),
    ),
    body: TextField(
      controller: controller,
      keyboardType: TextInputType.multiline,
      maxLines: null,
    ),
  );
}

完整代码：

    import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  TextEditingController controller = TextEditingController();

  int cursorPosition = 0;

  @override
  void initState() {
    controller.addListener(() {
      setState(() {
        cursorPosition = controller.selection.base.offset;
        print("cursorPosition: $cursorPosition");
      });
    });
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          widget.title,
        ),
      ),
      body: TextField(
        controller: controller,
        keyboardType: TextInputType.multiline,
        maxLines: null,
      ),
    );
  }
}
于 2021-02-19T16:22:58.460 回答
-1 
onChanged: (value) {
      int pos = controller.selection.start;
      print(
        "Position: $pos",
      );
    },
于 2021-02-19T06:50:32.507 回答