window_manager_plus

This plugin allows Flutter desktop apps to create and manage multiple windows, such as resizing and repositioning, and communicate between them.

This is a fork and a re-work of the original window_manager plugin. With inspiration from the desktop_multi_window plugin, this new implementation allows the creation and management of multiple windows.

Linux is not currently supported.

Platform Support
Quick Start
- Setup to support multiple windows
  - macOS
  - Windows
- Usage
Articles
API
- WindowManagerPlus
  - Methods
  - Static Methods
- WindowListener
  - Methods
Contributors
License

Platform Support

Linux	macOS	Windows
❌	✅	✅️

Quick Start

Setup to support multiple windows

macOS

Change the file macos/Runner/MainFlutterWindow.swift as follows:

import Cocoa
import FlutterMacOS
+ import window_manager_plus

class MainFlutterWindow: NSPanel {
    override func awakeFromNib() {
        let flutterViewController = FlutterViewController.init()
        let windowFrame = self.frame
        self.contentViewController = flutterViewController
        self.setFrame(windowFrame, display: true)
        
        RegisterGeneratedPlugins(registry: flutterViewController)
+        
+        WindowManagerPlusPlugin.RegisterGeneratedPlugins = RegisterGeneratedPlugins
        
        super.awakeFromNib()
    }
    
    override public func order(_ place: NSWindow.OrderingMode, relativeTo otherWin: Int) {
        super.order(place, relativeTo: otherWin)
        hiddenWindowAtLaunch()
    }
}

Change the file macos/Runner/AppDelegate.swift as follows:

import Cocoa
import FlutterMacOS
+ import window_manager_plus

@main
class AppDelegate: FlutterAppDelegate {
  override func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
-    return true
+    return NSApp.windows.filter({$0 is MainFlutterWindow || $0 is WindowManagerPlusFlutterWindow}).count == 1 // or return false
  }
}

Without changing the return logic, the application will close when the main flutter window is closed.

Windows

Change the file windows/runner/main.cpp as follows:

#include <flutter/dart_project.h>
#include <flutter/flutter_view_controller.h>
#include <windows.h>

#include "flutter_window.h"
#include "utils.h"

+ #include <iostream>
+ #include "window_manager_plus/window_manager_plus_plugin.h"

int APIENTRY wWinMain(_In_ HINSTANCE instance,
                      _In_opt_ HINSTANCE prev,
                      _In_ wchar_t* command_line,
                      _In_ int show_command) {
  // Attach to console when present (e.g., 'flutter run') or create a
  // new console when running with a debugger.
  if (!::AttachConsole(ATTACH_PARENT_PROCESS) && ::IsDebuggerPresent()) {
    CreateAndAttachConsole();
  }

  // Initialize COM, so that it is available for use in the library and/or
  // plugins.
  ::CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED);

  flutter::DartProject project(L"data");

  std::vector<std::string> command_line_arguments = GetCommandLineArguments();

  project.set_dart_entrypoint_arguments(std::move(command_line_arguments));

  FlutterWindow window(project);
  Win32Window::Point origin(10, 10);
  Win32Window::Size size(1280, 720);
  if (!window.Create(L"window_manager_example", origin, size)) {
    return EXIT_FAILURE;
  }
-  window.SetQuitOnClose(true);
+  window.SetQuitOnClose(false);
+
+  WindowManagerPlusPluginSetWindowCreatedCallback(
+      [](std::vector<std::string> command_line_arguments) {
+        flutter::DartProject project(L"data");
+
+        project.set_dart_entrypoint_arguments(
+            std::move(command_line_arguments));
+
+        auto window = std::make_shared<FlutterWindow>(project);
+        Win32Window::Point origin(10, 10);
+        Win32Window::Size size(1280, 720);
+        // Check whether window->Create or window->CreateAndShow is available.
+        // Take a look at the code above for the main flutter window and 
+        // what method the variable "FlutterWindow window(project)" calls
+        if (!window->Create(L"window_manager_example", origin, size)) {
+          std::cerr << "Failed to create a new window" << std::endl;
+        }
+        window->SetQuitOnClose(false);
+        return std::move(window);
+      });

  ::MSG msg;
  while (::GetMessage(&msg, nullptr, 0, 0)) {
    ::TranslateMessage(&msg);
    ::DispatchMessage(&msg);
  }

  ::CoUninitialize();
  return EXIT_SUCCESS;
}

window->SetQuitOnClose(false); is necessary to prevent the application from closing when the window is closed.

If you want to close the App only when the main window is closed, you can set window->SetQuitOnClose(true); in the main window. The others called inside the WindowManagerPlusPluginSetWindowCreatedCallback should be set to false.

Usage

You must call WindowManagerPlus.ensureInitialized static method and await it before using any WindowManagerPlus methods or WindowManagerPlus.current. It is used to initialize the plugin with the current window ID.

When creating a new window, the args parameter of the main function will have the window ID as a String. You must parse it to an integer and pass it to the WindowManagerPlus.ensureInitialized method. If the args parameter is empty or the first argument is not an integer, then we are in the main window, which ID is exactly 0.

The other arguments will contain the arguments passed to the WindowManagerPlus.createWindow method, if any.

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

// Must add List<String> args parameter to your main function.
void main(List<String> args) async {
  WidgetsFlutterBinding.ensureInitialized();
  // await the initialization of the plugin.
  // Here is an example of how to use ensureInitialized in the main function:
  await WindowManagerPlus.ensureInitialized(args.isEmpty ? 0 : int.tryParse(args[0]) ?? 0);
  
  // Now you can use the plugin, such as WindowManagerPlus.current
  WindowOptions windowOptions = WindowOptions(
    size: Size(800, 600),
    center: true,
    backgroundColor: Colors.transparent,
    skipTaskbar: false,
    titleBarStyle: TitleBarStyle.hidden,
  );
  WindowManagerPlus.current.waitUntilReadyToShow(windowOptions, () async {
    await WindowManagerPlus.current.show();
    await WindowManagerPlus.current.focus();
  });

  runApp(MyApp());
}

Create a new window

You can create a new window by calling the WindowManagerPlus.createWindow static method. If you want control the new window, you can use the return value of the method, which returns a WindowManagerPlus instance.

final newWindow = await WindowManagerPlus.createWindow(['my test arg 1', 'my test arg 2']);
if (newWindow != null) {
  print('New Created Window: $newWindow');
}

Communication between windows

You can communicate with another window by using the WindowManagerPlus.invokeMethodToWindow method. The first parameter is the ID of the window you want to communicate with. The second parameter is the method name you want to call. The third parameter is the arguments you want to pass to the method, if any.

The other window must register and implement the WindowListener class and override the WindowListener.onEventFromWindow method to receive the event.

// assuming we are in the first window, Window ID 0, and we want to communicate with the second window.
final secondWindowId = 1; // ID of the second window
final result = await WindowManagerPlus.current.invokeMethodToWindow(secondWindowId, 'myTestMethod', ['arg1', 'arg2']);
// the result will be 'Hello from Window 1'

// assuming we are in the second window, Window ID 1
class _MyWidgetState extends State<MyWidget> with WindowListener {

  // ...

  @override
  void initState() {
    WindowManagerPlus.current.addListener(this);
    super.initState();
  }

  @override
  void dispose() {
    WindowManagerPlus.current.removeListener(this);
    super.dispose();
  }
  
  // ...
  
  @override
  Future<dynamic> onEventFromWindow(String eventName, int fromWindowId, dynamic arguments) async {
    print('[${WindowManagerPlus.current}] Event $eventName from Window $fromWindowId with arguments $arguments');
    return 'Hello from ${WindowManagerPlus.current}';
  }
}

Using WindowManagerPlus.getAllWindowManagerIds() static method you can get all the window manager ids available.

Please see the example app of this plugin for a full example.

Listening events

The WindowListener mixin class is used to listen to window events. If this is used as a Global Listener using the WindowManagerPlus.addGlobalListener static method, the windowId parameter will be the ID of the window that emitted the event, otherwise, it will be always null.

import 'package:flutter/cupertino.dart';
import 'package:window_manager_plus/window_manager_plus.dart';

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> with WindowListener {
  @override
  void initState() {
    super.initState();
    WindowManagerPlus.current.addListener(this);
  }

  @override
  void dispose() {
    WindowManagerPlus.current.removeListener(this);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    // ...
  }

  @override
  void onWindowEvent(String eventName, [int? windowId]) {
    print('[WindowManager] onWindowEvent: $eventName');
  }

  @override
  void onWindowClose([int? windowId]) {
    // do something
  }

  @override
  void onWindowFocus([int? windowId]) {
    // do something
  }

  @override
  void onWindowBlur([int? windowId]) {
    // do something
  }

  @override
  void onWindowMaximize([int? windowId]) {
    // do something
  }

  @override
  void onWindowUnmaximize([int? windowId]) {
    // do something
  }

  @override
  void onWindowMinimize([int? windowId]) {
    // do something
  }

  @override
  void onWindowRestore([int? windowId]) {
    // do something
  }

  @override
  void onWindowResize([int? windowId]) {
    // do something
  }

  @override
  void onWindowMove([int? windowId]) {
    // do something
  }

  @override
  void onWindowEnterFullScreen([int? windowId]) {
    // do something
  }

  @override
  void onWindowLeaveFullScreen([int? windowId]) {
    // do something
  }
}

Quit on close

If you need to use the hide method, you need to disable QuitOnClose.

macOS

Change the file macos/Runner/AppDelegate.swift as follows:

import Cocoa
import FlutterMacOS

@NSApplicationMain
class AppDelegate: FlutterAppDelegate {
  override func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
-    return true
+    return false
  }
}

Windows

Change the file windows/runner/main.cpp as follows:

#include <flutter/dart_project.h>
#include <flutter/flutter_view_controller.h>
#include <windows.h>

#include <iostream>

#include "flutter_window.h"
#include "utils.h"

int APIENTRY wWinMain(_In_ HINSTANCE instance,
                      _In_opt_ HINSTANCE prev,
                      _In_ wchar_t* command_line,
                      _In_ int show_command) {
  // Attach to console when present (e.g., 'flutter run') or create a
  // new console when running with a debugger.
  if (!::AttachConsole(ATTACH_PARENT_PROCESS) && ::IsDebuggerPresent()) {
    CreateAndAttachConsole();
  }

  // Initialize COM, so that it is available for use in the library and/or
  // plugins.
  ::CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED);

  flutter::DartProject project(L"data");

  std::vector<std::string> command_line_arguments = GetCommandLineArguments();

  project.set_dart_entrypoint_arguments(std::move(command_line_arguments));

  FlutterWindow window(project);
  Win32Window::Point origin(10, 10);
  Win32Window::Size size(1280, 720);
  if (!window.CreateAndShow(L"window_manager_example", origin, size)) {
    return EXIT_FAILURE;
  }
-  window.SetQuitOnClose(true);
+  window.SetQuitOnClose(false);

  ::MSG msg;
  while (::GetMessage(&msg, nullptr, 0, 0)) {
    ::TranslateMessage(&msg);
    ::DispatchMessage(&msg);
  }

  ::CoUninitialize();
  return EXIT_SUCCESS;
}

Confirm before closing

import 'package:flutter/cupertino.dart';
import 'package:window_manager/window_manager.dart';

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> with WindowListener {
  @override
  void initState() {
    super.initState();
    WindowManagerPlus.current.addListener(this);
    _init();
  }

  @override
  void dispose() {
    WindowManagerPlus.current.removeListener(this);
    super.dispose();
  }

  void _init() async {
    // Add this line to override the default close handler
    await WindowManagerPlus.current.setPreventClose(true);
    setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    // ...
  }

  @override
  void onWindowClose() async {
    bool _isPreventClose = await WindowManagerPlus.current.isPreventClose();
    if (_isPreventClose) {
      showDialog(
        context: context,
        builder: (_) {
          return AlertDialog(
            title: Text('Are you sure you want to close this window?'),
            actions: [
              TextButton(
                child: Text('No'),
                onPressed: () {
                  Navigator.of(context).pop();
                },
              ),
              TextButton(
                child: Text('Yes'),
                onPressed: () {
                  Navigator.of(context).pop();
                  await WindowManagerPlus.current.destroy();
                },
              ),
            ],
          );
        },
      );
    }
  }
}

Hidden at launch

Linux

Change the file linux/my_application.cc as follows:


...

// Implements GApplication::activate.
static void my_application_activate(GApplication* application) {
  
  ...

  gtk_window_set_default_size(window, 1280, 720);
-  gtk_widget_show(GTK_WIDGET(window));
+  gtk_widget_realize(GTK_WIDGET(window));

  g_autoptr(FlDartProject) project = fl_dart_project_new();
  fl_dart_project_set_dart_entrypoint_arguments(project, self->dart_entrypoint_arguments);

  FlView* view = fl_view_new(project);
  gtk_widget_show(GTK_WIDGET(view));
  gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(view));

  fl_register_plugins(FL_PLUGIN_REGISTRY(view));

  gtk_widget_grab_focus(GTK_WIDGET(view));
}

...

macOS

Change the file macos/Runner/MainFlutterWindow.swift as follows:

import Cocoa
import FlutterMacOS
+import window_manager

class MainFlutterWindow: NSWindow {
    override func awakeFromNib() {
        let flutterViewController = FlutterViewController.init()
        let windowFrame = self.frame
        self.contentViewController = flutterViewController
        self.setFrame(windowFrame, display: true)

        RegisterGeneratedPlugins(registry: flutterViewController)

        super.awakeFromNib()
    }

+    override public func order(_ place: NSWindow.OrderingMode, relativeTo otherWin: Int) {
+        super.order(place, relativeTo: otherWin)
+        hiddenWindowAtLaunch()
+    }
}

Windows

Change the file windows/runner/win32_window.cpp as follows:

bool Win32Window::CreateAndShow(const std::wstring& title,
                                const Point& origin,
                                const Size& size) {
  ...                              
  HWND window = CreateWindow(
-      window_class, title.c_str(), WS_OVERLAPPEDWINDOW | WS_VISIBLE,
+      window_class, title.c_str(),
+      WS_OVERLAPPEDWINDOW, // do not add WS_VISIBLE since the window will be shown later
      Scale(origin.x, scale_factor), Scale(origin.y, scale_factor),
      Scale(size.width, scale_factor), Scale(size.height, scale_factor),
      nullptr, nullptr, GetModuleHandle(nullptr), this);

Since flutter 3.7 new windows project Change the file windows/runner/flutter_window.cpp as follows:

bool FlutterWindow::OnCreate() {
  ...
  flutter_controller_->engine()->SetNextFrameCallback([&]() {
-   this->Show();
+   //delete this->Show()
  });

Make sure to call setState once on the onWindowFocus event.

import 'package:flutter/cupertino.dart';
import 'package:window_manager/window_manager.dart';

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> with WindowListener {
  @override
  void initState() {
    super.initState();
    WindowManagerPlus.current.addListener(this);
  }

  @override
  void dispose() {
    WindowManagerPlus.current.removeListener(this);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    // ...
  }

  @override
  void onWindowFocus() {
    // Make sure to call once.
    setState(() {});
    // do something
  }
}

Articles

API

WindowManagerPlus

Methods

addListener(WindowListener listener) → void

Add a listener to the window.

blur() → Future<void>

Removes focus from the window.

center({bool animate = false}) → Future<void>

Moves window to the center of the screen.

close() → Future<void>

Try to close the window.

destroy() → Future<void>

Force closing the window.

dock({required DockSide side, required int width}) → Future<void>

Docks the window. only works on Windows

focus() → Future<void>

Focuses on the window.

getBounds() → Future<Rect>

Returns Rect - The bounds of the window as Object.

getDevicePixelRatio() → double

Get the device pixel ratio.

getOpacity() → Future<double>

Returns double - between 0.0 (fully transparent) and 1.0 (fully opaque).

getPosition() → Future<Offset>

Returns Offset - Contains the window's current position.

getSize() → Future<Size>

Returns Size - Contains the window's width and height.

getTitle() → Future<String>

Returns String - The title of the native window.

getTitleBarHeight() → Future<int>

Returns int - The title bar height of the native window.

hasShadow() → Future<bool>

Returns bool - Whether the window has a shadow. On Windows, always returns true unless window is frameless.

hide() → Future<void>

Hides the window.

invokeMethodToWindow(int targetWindowId, String method, [dynamic args]) → Future

Invokes a method on the window with id targetWindowId. It could return a Future that resolves to the return value of the invoked method, otherwise null. Use WindowListener.onEventFromWindow to listen for the event.

isAlwaysOnBottom() → Future<bool>

Returns bool - Whether the window is always below other windows.

isAlwaysOnTop() → Future<bool>

Returns bool - Whether the window is always on top of other windows.

isClosable() → Future<bool>

Returns bool - Whether the window can be manually closed by user.

isDockable() → Future<bool>

Returns bool - Whether the window is dockable or not.

isDocked() → Future<DockSide?>

Returns bool - Whether the window is docked.

isFocused() → Future<bool>

Returns bool - Whether window is focused.

isFullScreen() → Future<bool>

Returns bool - Whether the window is in fullscreen mode.

isMaximizable() → Future<bool>

Returns bool - Whether the window can be manually maximized by the user.

isMaximized() → Future<bool>

Returns bool - Whether the window is maximized.

isMinimizable() → Future<bool>

Returns bool - Whether the window can be manually minimized by the user.

isMinimized() → Future<bool>

Returns bool - Whether the window is minimized.

isMovable() → Future<bool>

Returns bool - Whether the window can be moved by user.

isPreventClose() → Future<bool>

Check if is intercepting the native close signal.

isResizable() → Future<bool>

Returns bool - Whether the window can be manually resized by the user.

isSkipTaskbar() → Future<bool>

Returns bool - Whether skipping taskbar is enabled.

isVisible() → Future<bool>

Returns bool - Whether the window is visible to the user.

isVisibleOnAllWorkspaces() → Future<bool>

Returns bool - Whether the window is visible on all workspaces.

maximize({bool vertically = false}) → Future<void>

Maximizes the window. vertically simulates aero snap, only works on Windows

minimize() → Future<void>

Minimizes the window. On some platforms the minimized window will be shown in the Dock.

popUpWindowMenu() → Future<void>

removeListener(WindowListener listener) → void

Remove a listener from the window.

restore() → Future<void>

Restores the window from minimized state to its previous state.

setAlignment(Alignment alignment, {bool animate = false}) → Future<void>

Move the window to a position aligned with the screen.

setAlwaysOnBottom(bool isAlwaysOnBottom) → Future<void>

Sets whether the window should show always below other windows.

setAlwaysOnTop(bool isAlwaysOnTop) → Future<void>

Sets whether the window should show always on top of other windows.

setAsFrameless() → Future<void>

You can call this to remove the window frame (title bar, outline border, etc), which is basically everything except the Flutter view, also can call setTitleBarStyle(TitleBarStyle.normal) or setTitleBarStyle(TitleBarStyle.hidden) to restore it.

setAspectRatio(double aspectRatio) → Future<void>

This will make a window maintain an aspect ratio.

setBackgroundColor(Color backgroundColor) → Future<void>

Sets the background color of the window.

setBadgeLabel([String? label]) → Future<void>

Set/unset label on taskbar(dock) app icon

setBounds(Rect? bounds, {Offset? position, Size? size, bool animate = false}) → Future<void>

Resizes and moves the window to the supplied bounds.

setBrightness(Brightness brightness) → Future<void>

Sets the brightness of the window.

setClosable(bool isClosable) → Future<void>

Sets whether the window can be manually closed by user.

setFullScreen(bool isFullScreen) → Future<void>

Sets whether the window should be in fullscreen mode.

setHasShadow(bool hasShadow) → Future<void>

Sets whether the window should have a shadow. On Windows, doesn't do anything unless window is frameless.

setIcon(String iconPath) → Future<void>

Sets window/taskbar icon.

setIgnoreMouseEvents(bool ignore, {bool forward = false}) → Future<void>

Makes the window ignore all mouse events.

setMaximizable(bool isMaximizable) → Future<void>

Sets whether the window can be manually maximized by the user.

setMaximumSize(Size size) → Future<void>

Sets the maximum size of window to width and height.

setMinimizable(bool isMinimizable) → Future<void>

Sets whether the window can be manually minimized by user.

setMinimumSize(Size size) → Future<void>

Sets the minimum size of window to width and height.

setMovable(bool isMovable) → Future<void>

Sets whether the window can be moved by user.

setOpacity(double opacity) → Future<void>

Sets the opacity of the window.

setPosition(Offset position, {bool animate = false}) → Future<void>

Moves window to position.

setPreventClose(bool isPreventClose) → Future<void>

Set if intercept the native close signal. May useful when combine with the onclose event listener. This will also prevent the manually triggered close event.