如何设置 showLicensePage function 以使用 Flutter？

Question

I'm wrapping up an ios app I am creating and realized I need to display the Flutter License somewhere in my settings screen.

I am trying to implement the showLicensePage function from Flutter but not sure how to go about this. https://api.flutter.dev/flutter/material/showLicensePage.html

How do I use this function?

import 'package:flutter/material.dart';

class FlutterLicense extends StatelessWidget {
  void showLicensePage({
    @required BuildContext context,
    String applicationName,
    String applicationVersion,
    Widget applicationIcon,
    String applicationLegalese,
    bool useRootNavigator = false,
  }) {
    assert(context != null);
    assert(useRootNavigator != null);
    Navigator.of(context, rootNavigator: useRootNavigator)
        .push(MaterialPageRoute<void>(
      builder: (BuildContext context) => LicensePage(
        applicationName: applicationName,
        applicationVersion: applicationVersion,
        applicationIcon: applicationIcon,
        applicationLegalese: applicationLegalese,
      ),
    ));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Color(0XFFeb1555),
        title: Text(
          'LICENSES',
          style: TextStyle(),
        ),
      ),
      body: SafeArea(
        child: SingleChildScrollView(
          child: Padding(
            padding: const EdgeInsets.all(20.0),
            child: Column(
              children: showLicensePage(context: null),
            ),
          ),
        ),
      ),
    );
  }
}

Answer 1

1. You are passing null to as the context parameter which is wrong. Do showLicensePage(context: context) instead.

2. The showLicensePage is a function which returns null so you cannot pass it as the children of the Column .

3. You do not need a dedicated widget to display your licenses page. The framework takes care of it for you.

Solution

On your settings page, you may have a widget on which when clicked, shows the license page. Just call the function showLicensePage(context: context) inside the onTap or onPressed of that widget.

Example

import 'package:flutter/material.dart';

class SettingsPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Center(
        child: FlatButton(
          onPressed: () {
            showLicensePage(
              context: context,
              // applicationIcon: Image.asset(name)
              // applicationName: "App Name"
              // Other parameters
            );
          },
          child: Text('Show Licenses'),
        ),
      ),
    );
  }
}

This code produces, this when the button is clicked: