Flutter 点击空白处关闭软键盘，点击非TextField 关闭软键盘的方法

在Flutter中，可以使用RawGestureDetector来监听空白处的点击事件，并通过SystemChannels.textInput.invokeMethod('hide')来隐藏软键盘。以下是实现点击空白处关闭软键盘的示例代码：

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(
      home: Scaffold(
        body: SafeArea(
          child: DismissKeyboard(
            child: Center(
              child: TextField(),
            ),
          ),
        ),
      ),
    );
  }
}
 
class DismissKeyboard extends StatefulWidget {
  final Widget child;
 
  DismissKeyboard({required this.child});
 
  @override
  _DismissKeyboardState createState() => _DismissKeyboardState();
}
 
class _DismissKeyboardState extends State<DismissKeyboard> {
  final FocusNode focusNode = FocusNode();
 
  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () {
        focusNode.unfocus();
        SystemChannels.textInput.invokeMethod('hide');
      },
      child: FocusScope.of(context).focusedChild != null
          ? RawGestureDetector(
              gestures: {
                TapGestureRecognizer: TapGestureRecognizer()..onTap = () => hideKeyboard(),
              },
              behavior: HitTestBehavior.opaque,
              child: widget.child,
            )
          : widget.child,
    );
  }
 
  void hideKeyboard() {
    focusNode.unfocus();
    SystemChannels.textInput.invokeMethod('hide');
  }
 
  @override
  void dispose() {
    focusNode.dispose();
    super.dispose();
  }
}

在这个示例中，我们创建了一个DismissKeyboard组件，它包装了需要使用的其他部分的UI。在DismissKeyboard的状态中，我们使用GestureDetector来监听点击事件，并且当点击发生时，如果当前焦点不是在TextField上，就会触发hideKeyboard方法，该方法会取消焦点并隐藏软键盘。