Commandline or GUI Windows

This plugin allows you to run a flutter windows app in gui, or commandline mode. io.dart is used to access stdout and stderr

Setup

If the setup isn't performed the below code will not run as expected

1. Import the package (add to pubspec.yaml and run pub get)
2. Open powershell and navigate to the root directory of your app. This is typically the directory where your pubspec.yaml resides.
3. run flutter pub run commandline_or_gui_windows:create If you want more details run flutter pub run commandline_or_gui_windows:create --help

Restore (not part of setup)

The below two options can be used to attempt to restore your project after using commandline_or_gui_windows.

Option 1 - restore only modified C++ files

1. Open powershell and navigate to the root directory of your app. This is typically the directory where your pubspec.yaml resides.
2. run flutter pub run commandline_or_gui_windows:restore If you want more details run flutter pub run commandline_or_gui_windows:restore --help

Option 2 - restore all C++ files

1. delete windows folder C:\project_path\windows\
2. Open powershell and navigate to the root directory of your app. This is typically the directory where your pubspec.yaml resides.
3. run flutter create .

Please Post Questions on StackOverflow, and tag @CatTrain (user:16200950)

stackoverflow.com/

Importing

YAML

dependencies:
    commandline_or_gui_windows: ^2.1.0

Dart

import 'package:commandline_or_gui_windows/commandline_or_gui_windows.dart';

Example - Commandline Only

Note that at least one argument must be passed or the app will crash and enter gui mode

import 'package:commandline_or_gui_windows/commandline_or_gui_windows.dart';
import 'dart:io';

void main(List<String> args) {
  CommandlineOrGuiWindows.runAppCommandlineOrGUI(
    argsCount: args.length,
    commandlineRun: () async {
      stdout.writeln("Hello world");
      stderr.writeln("Oh no!");
    },
  );
}

Example - GUI Only

Note that it will crash if any commandline arguments are passed, because commandlineRun isn't set

import 'package:commandline_or_gui_windows/commandline_or_gui_windows.dart';
import 'package:flutter/material.dart';

void main(List<String> args) {
  CommandlineOrGuiWindows.runAppCommandlineOrGUI(
    argsCount: args.length,
    gui: const MaterialApp(
      home: Scaffold(
        body: Text("Hello World"),
      ),
    ),
  );
}

Example - GUI or Commandline

This example uses args.dart package, and dart:io (for accessing stdio).

// flutter library for gui
import 'package:flutter/material.dart';

// import of the plugin
import 'package:commandline_or_gui_windows/commandline_or_gui_windows.dart';

// used to write to stdout and stderr
import 'dart:io';

// not part of plugin, added to add commandline input
import 'package:args/args.dart';

/*
  Commandline and dart
    https://dart.dev/tutorials/server/cmdline
  Error codes:
    https://docs.microsoft.com/en-us/windows/win32/debug/system-error-codes--0-499-
 */
void main(List<String> args) async {
  // create flags
  ArgParser parser = ArgParser();
  parser.addOption(
    "two_multiplied_by",
    abbr: "m",
    mandatory: false,
    help: "Pass an int, and see 2 * int",
  );
  parser.addFlag(
    "help",
    abbr: "h",
    negatable: true,
    defaultsTo: false,
    help: "If passed help for flags is displayed",
  );

  // parse results exit if error
  ArgResults results;
  try {
    // parse
    results = parser.parse(args);

    // if help is passed display help
    if (results["help"]) {
      stdout.writeln(parser.usage);
      exit(0);
    }
  } catch (err) {
    stderr.writeln(err.toString());
    exit(1);
  }

  /*
    Runs in commandline mode if one or more args are passed
    trys to multiply by the value passed by two_multiplied_by
    and outputs result to stdout
    on error prints to stderr
    if no args, runs in gui mode
   */
  CommandlineOrGuiWindows.runAppCommandlineOrGUI(
    // if there are 1 or more args passed the app will run in commandline mode
    argsCount: args.length,

    // if false the app won't close at the end of commandline mode
    // this is allows you to work on code without builing after every change
    // set to true if you want the app to close when commandline finishes
    closeOnCompleteCommandlineOptionOnly: false,

    // when in commandline mode run the below function
    commandlineRun: () async {
      // if a value is passed attempt to parse and multiply by 2
      if (results["two_multiplied_by"] != null) {
        try {
          stdout.writeln(int.parse(results["two_multiplied_by"]) * 2);
        } catch (err) {
          stderr.writeln(
              "Unable to multiply, 2 * ${results["two_multiplied_by"]}:\n${err.toString()}");
          CommandlineOrGuiWindows.commandlineExit(
              exitCode: 87); // ERROR_INVALID_PARAMETER
        }
        // write error to stderr and send 1 as error exit code
      } else {
        stdout.writeln("You didn't pass anything to be multiplied by 2");
      }
    },

    // gui to be shown when running in gui mode
    gui: const MaterialApp(
      home: Scaffold(
        body: Center(
          child: Text("Hello World"),
        ),
      ),
    ),
  );
}

Running code in commandline mode

Debug

Using PowerShell, in the above example, "GUI or Commandline" the code can be run in debug mode using the following flutter run command

flutter run -a -m -a 5

Note that -a indicates the following value will be passed to your app. Run the below command for further documentation

flutter run --help

Release

Using PowerShell, first build your app for release using the following command, from the root of your app typically the same folder as your pubspec.yaml

flutter build windows --release

Then navigate to the build location from the root trypically .\build\windows\runner\Release, and now you can run the example without -a

.\commandline_or_gui_windows_example.exe -m 5

Functions

static Future<void> runAppCommandlineOrGUI({
  Widget? gui,
  Future<void> Function()? commandlineRun,
  required int argsCount,
  bool closeOnCompleteCommandlineOptionOnly = true,
  int commandlineExitSuccessCode = 0,
}) async

• runs runApp, is a replacment for runApp. Allows running of the app in commandline or GUI mode.
• Parameters:
  • Widget? gui
    • The gui that will be displayed, only required if there are one or more commandline arguments passed
  • Future<void> Function()? commandlineRun
    • Function that must be passed if there are one or more commandline arguments passed
    • This is the code that is run when in commandline mode
  • required int argsCount
    • if > 0 run in commandline mode
      • commandlineRun must be passed
    • if < 1
      • gui must be passed
  • bool closeOnCompleteCommandlineOptionOnly = true
    • closes the app when commandlineRun is done being run
    • Only relevant if in commandline mode
  • int commandlineExitSuccesCode = 0
    • exit code that is sent when the app exits in commandline mode successfully

static commandlineExit({int exitCode = 0})

• Exits the commandline app when called
  • should only be called from the afterLoaded function passed to runAppCommandlineOrGUI
  • will not close app if closeOnCompleteCommandlineOptionOnly passed to runAppCommandlineOrGUI is false
    • this allows for debugging in certain scenarios

Ref

github.com/Honeyman-Applications/commandline_or_gui_windows/ api.flutter.dev/flutter/material/CircularProgressIndicator-class.html pub.dev/packages/args dart.dev/tutorials/server/cmdline docs.microsoft.com/en-us/windows/win32/debug/system-error-codes--0-499- api.flutter.dev/flutter/dart-io/dart-io-library.html