看起来不同的版本用不同的方法。我使用的是Flutter v1.17.1，下面的操作适合我。

onTap: () {
    FocusScopeNode currentFocus = FocusScope.of(context);
    if (!currentFocus.hasPrimaryFocus && currentFocus.focusedChild != null) {
       currentFocus.focusedChild.unfocus();
    }
}

使用SystemChannels.textInput.invokeMethod (' TextInput.hide ');。当屏幕加载时，它将关闭/解除键盘。

void initState() {
  super.initState();
  SystemChannels.textInput.invokeMethod('TextInput.hide');
}

你可以用这个。

FocusScope或(上下文)。requestFocus (FocusNode ());

你可以使用这个手势侦测器的onTap或者像这样的InkWell。

“GestureDetector ( onTap:() {' //这个焦点范围将关闭键盘 FocusScope.of(上下文).requestFocus (FocusNode ()); forgotPasswordAPI (emailController.text); }”、“

你可以用"GestureDetector"来包装你的小部件，然后将"FocusScope.of(context).unfocus()"赋值给它的onTap函数

GestureDetector(
 onTap: () => FocusScope.of(context).unfocus(),
 child: child,
);

你也可以为你的文本域声明一个focusNode，当你完成时，你可以在那个focusNode上调用unfocus方法 然后处理它

class MyHomePage extends StatefulWidget {
  MyHomePageState createState() => new MyHomePageState();
}

class MyHomePageState extends State<MyHomePage> {
  TextEditingController _controller = new TextEditingController();

/// declare focus
  final FocusNode _titleFocus = FocusNode();

  @override
  void dispose() {
    _titleFocus.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(),
      floatingActionButton: new FloatingActionButton(
        child: new Icon(Icons.send),
        onPressed: () {
          setState(() {
            // send message
            // dismiss on screen keyboard here

            _titleFocus.unfocus();
            _controller.clear();
          });
        },
      ),
      body: new Container(
        alignment: FractionalOffset.center,
        padding: new EdgeInsets.all(20.0),
        child: new TextFormField(
          controller: _controller,
          focusNode: _titleFocus,
          decoration: new InputDecoration(labelText: 'Example Text'),
        ),
      ),
    );
  }
}

您可以使用FocusNode类中的unfocus()方法。

import 'package:flutter/material.dart';

class MyHomePage extends StatefulWidget {
  MyHomePageState createState() => new MyHomePageState();
}

class MyHomePageState extends State<MyHomePage> {
  TextEditingController _controller = new TextEditingController();
  FocusNode _focusNode = new FocusNode(); //1 - declare and initialize variable

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(),
      floatingActionButton: new FloatingActionButton(
        child: new Icon(Icons.send),
        onPressed: () {
            _focusNode.unfocus(); //3 - call this method here
        },
      ),
      body: new Container(
        alignment: FractionalOffset.center,
        padding: new EdgeInsets.all(20.0),
        child: new TextFormField(
          controller: _controller,
          focusNode: _focusNode, //2 - assign it to your TextFormField
          decoration: new InputDecoration(labelText: 'Example Text'),
        ),
      ),
    );
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      home: new MyHomePage(),
    );
  }
}

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