How can I dismiss the on screen keyboard?

问题:

I am collecting user input with a TextFormField and when the user presses a FloatingActionButton indicating they are done, I want to dismiss the on screen keyboard.

How do I make the keyboard go away automatically?

import 'package:flutter/material.dart';

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

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

  @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
            _controller.clear();
          });
        },
      ),
      body: new Container(
        alignment: FractionalOffset.center,
        padding: new EdgeInsets.all(20.0),
        child: new TextFormField(
          controller: _controller,
          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());
}

回答1:

You can dismiss the keyboard by taking away the focus of the TextFormField and giving it to an unused FocusNode:

FocusScope.of(context).requestFocus(new FocusNode());

回答2:

Solution with FocusScope doesn't work for me. I found another:

import 'package:flutter/services.dart';

SystemChannels.textInput.invokeMethod('TextInput.hide');

It solved my problem.

回答3:

Take a GestureDetector on the top level of all widgets and onTap() of that gestureDetector and call

FocusScope.of(context).requestFocus(new FocusNode());

回答4:

None of the above solutions don't work for me.

Flutter suggests this - Put your widget inside new GestureDetector() on which tap will hide keyboard and onTap use FocusScope.of(context).requestFocus(new FocusNode())

class Home extends StatelessWidget {
@override
  Widget build(BuildContext context) {
    var widget = new MaterialApp(
        home: new Scaffold(
            body: new Container(
                height:500.0,
                child: new GestureDetector(
                    onTap: () {
                        FocusScope.of(context).requestFocus(new FocusNode());
                    },
                    child: new Container(
                        color: Colors.white,
                        child:  new Column(
                            mainAxisAlignment:  MainAxisAlignment.center,
                            crossAxisAlignment: CrossAxisAlignment.center,

                            children: [
                                new TextField( ),
                                new Text("Test"),                                
                            ],
                        )
                    )
                )
            )
        ),
    );

    return widget;
}}