Question

我想监听 textEditingController 中光标的变化，但目前监听器只对字符的添加和删除做出反应，有没有办法解决这个问题？

例如在带有 +7 (111) 111-11-11 的 TextField 中，如果用户在“+7”之前设置光标，我想将光标设置回位置 = 3

Answer 1

我不确定，但这是您想要做的吗？

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: 'Demo',
      home: MyHomePage(title: 'Demo Home Page'),
    );
  }
}

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

  final String title;

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

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

  @override
  void initState() {
    super.initState();
    _controller.addListener(_setPos3);
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  void _setPos3() {
    if (_controller.selection.baseOffset == 0 &&
        _controller.selection.extentOffset == 0 &&
        3 <= _controller.text.length) {
      _controller.value = _controller.value.copyWith(
        selection: const TextSelection(baseOffset: 3, extentOffset: 3),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: TextFormField(
          controller: _controller,
        ),
      ),
    );
  }
}

聆听 TextSelection 的变化

1 个答案: