✨ Merge branch 'plugin', Add support for the JSON MethodChannel Plugins

Author: Drakirus

README.md

@@ -168,6 +168,7 @@ go build
 </details>
 
 
+
 ## Flutter Demos Projects
 
 The examples are available [here](./example/).
@@ -179,16 +180,20 @@ The examples are available [here](./example/).
 - [x] Linux :penguin:
 - [x] Windows :checkered_flag:
 - [x] MacOS :apple:
-- [x] Text input
-- [ ] Plugins
 - [x] Importable go library
-- [x] Clipboard (through shortcuts)
-- [ ] Clipboard (through the click)
-- [x] Keyboard shortcuts
-   - [x] <kbd>ctrl-c</kbd>  <kbd>ctrl-v</kbd>  <kbd>ctrl-x</kbd>  <kbd>ctrl-a</kbd>
-   - [x] <kbd>Home</kbd>  <kbd>End</kbd>  <kbd>shift-Home</kbd>  <kbd>shift-End</kbd>
-   - [x] <kbd>Left</kbd>  <kbd>ctrl-Left</kbd>  <kbd>ctrl-shift-Left</kbd>
-   - [x] <kbd>Right</kbd>  <kbd>ctrl-Right</kbd>  <kbd>ctrl-shift-Right</kbd>
-   - [x] <kbd>Backspace</kbd>  <kbd>ctrl-Backspace</kbd> <kbd>Delete</kbd>
-   - [ ] <kbd>ctrl-Delete</kbd>
-- [ ] Key events
+- [ ] Plugins [Medium article on how the the Flutter's messaging works](https://medium.com/flutter-io/flutter-platform-channels-ce7f540a104e)
+   - [x] JSON MethodChannel
+   - [ ] StandardMethodCodec, ...
+- [ ] System plugins [Platform channels used by the Flutter system](https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/services/system_channels.dart)
+  - [x] Window Title
+  - [x] Text input
+  - [x] Clipboard (through shortcuts)
+  - [ ] Clipboard (through the click)
+  - [x] Keyboard shortcuts
+    - [x] <kbd>ctrl-c</kbd>  <kbd>ctrl-v</kbd>  <kbd>ctrl-x</kbd>  <kbd>ctrl-a</kbd>
+    - [x] <kbd>Home</kbd>  <kbd>End</kbd>  <kbd>shift-Home</kbd>  <kbd>shift-End</kbd>
+    - [x] <kbd>Left</kbd>  <kbd>ctrl-Left</kbd>  <kbd>ctrl-shift-Left</kbd>
+    - [x] <kbd>Right</kbd>  <kbd>ctrl-Right</kbd>  <kbd>ctrl-shift-Right</kbd>
+    - [x] <kbd>Backspace</kbd>  <kbd>ctrl-Backspace</kbd> <kbd>Delete</kbd>
+    - [ ] <kbd>ctrl-Delete</kbd>
+  - [ ] Key events

example/simpleDemo/flutter_project/demo/lib/main.dart

@@ -3,6 +3,9 @@ import 'package:flutter/material.dart';
 import 'package:flutter/foundation.dart'
     show debugDefaultTargetPlatformOverride;
 
+import 'package:flutter/services.dart';
+import 'dart:async';
+
 void main() {
   // Desktop platforms aren't a valid platform.
   debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
@@ -31,11 +34,26 @@ class MyHomePage extends StatefulWidget {
   final String title;
 
   @override
-  _MyHomePageState createState() => new _MyHomePageState();
+  _MyHomePageState createState() {
+    return new _MyHomePageState();
+  }
 }
 
 class _MyHomePageState extends State<MyHomePage> {
+
+
+  static MethodChannel _channel = new MethodChannel('plugin_demo', new JSONMethodCodec());
+  Future GetVersion() async {
+    var res = await _channel.invokeMethod('getNumber');
+    print(res);
+    setState(() {
+      _counter = res;
+    });
+  }
+
+
   int _counter = 0;
+  bool _ok = false;
 
   void _incrementCounter() {
     setState(() {
@@ -45,6 +63,10 @@ class _MyHomePageState extends State<MyHomePage> {
 
   @override
   Widget build(BuildContext context) {
+    if (!_ok) {
+      GetVersion();
+      _ok = true;
+    }
     return new Scaffold(
       appBar: new AppBar(
         title: new Text(widget.title),

example/simpleDemo/flutter_project/demo/pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: analyzer
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.32.5"
+    version: "0.33.0"
   args:
     dependency: transitive
     description:
@@ -63,7 +63,7 @@ packages:
       name: csslib
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.14.5"
+    version: "0.14.6"
   cupertino_icons:
     dependency: "direct main"
     description:
@@ -87,7 +87,7 @@ packages:
       name: front_end
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.4+1"
+    version: "0.1.6"
   glob:
     dependency: transitive
     description:
@@ -108,7 +108,7 @@ packages:
       name: http
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.11.3+17"
+    version: "0.12.0"
   http_multi_server:
     dependency: transitive
     description:
@@ -150,7 +150,7 @@ packages:
       name: kernel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.4+1"
+    version: "0.3.6"
   logging:
     dependency: transitive
     description:
@@ -206,7 +206,7 @@ packages:
       name: package_resolver
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "1.0.6"
   path:
     dependency: transitive
     description:
@@ -288,7 +288,7 @@ packages:
       name: source_maps
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.10.7"
+    version: "0.10.8"
   source_span:
     dependency: transitive
     description:
@@ -330,7 +330,7 @@ packages:
       name: test
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0"
+    version: "1.3.4"
   typed_data:
     dependency: transitive
     description:
@@ -381,4 +381,4 @@ packages:
     source: hosted
     version: "2.1.15"
 sdks:
-  dart: ">=2.0.0-dev.68.0 <3.0.0"
+  dart: ">=2.0.0 <3.0.0"

example/simpleDemo/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bufio"
 	"image"
 	_ "image/png"
 	"log"
@@ -9,6 +10,7 @@ import (
 	"runtime"
 
 	gutter "github.com/Drakirus/go-flutter-desktop-embedder"
+	"github.com/Drakirus/go-flutter-desktop-embedder/flutter"
 
 	"github.com/go-gl/glfw/v3.2/glfw"
 )
@@ -29,6 +31,7 @@ func main() {
 		gutter.OptionWindowInitializer(setIcon),
 		gutter.OptionPixelRatio(1.2),
 		gutter.OptionVMArguments([]string{"--dart-non-checked-mode", "--observatory-port=50300"}),
+		gutter.OptionAddPluginReceiver(ownPlugin, "plugin_demo"),
 	}
 
 	if err = gutter.Run(options...); err != nil {
@@ -51,3 +54,26 @@ func setIcon(window *glfw.Window) error {
 	window.SetIcon([]image.Image{img})
 	return nil
 }
+
+// Plugin that read the stdin and send the number to the dart side
+func ownPlugin(
+	platMessage flutter.PlatformMessage,
+	flutterEngine *flutter.EngineOpenGL,
+	window *glfw.Window,
+) bool {
+	if platMessage.Message.Method != "getNumber" {
+		log.Printf("Unhandled platform method: %#v from channel %#v\n",
+			platMessage.Message.Method, platMessage.Channel)
+		return false
+	}
+
+	go func() {
+		reader := bufio.NewReader(os.Stdin)
+		print("Reading (A number): ")
+		s, _ := reader.ReadString('\n')
+		flutterEngine.SendPlatformMessageResponse(platMessage, []byte("[ "+s+" ]"))
+	}()
+
+	return true
+
+}

example/stocks/main.go

@@ -22,7 +22,7 @@ func main() {
 		// gutter.OptionICUDataPath("./FlutterEmbedder.framework/Resources/icudtl.dat"),             // OSX
 		gutter.OptionWindowDimension(800, 600),
 		gutter.OptionWindowInitializer(setIcon),
-		gutter.OptionPixelRatio(1.9),
+		gutter.OptionPixelRatio(1.2),
 		gutter.OptionVMArguments([]string{"--dart-non-checked-mode", "--observatory-port=50300"}),
 	}
 

flutter/flutter.go

@@ -12,7 +12,17 @@ import (
 )
 
 // the current FlutterEngine running (associated with his callback)
-var globalFlutterOpenGL EngineOpenGL
+var flutterEngines []*EngineOpenGL
+
+// SelectEngine return a EngineOpenGL from an index
+func SelectEngine(index int) *EngineOpenGL {
+	return flutterEngines[index]
+}
+
+// NumberOfEngines return the number of engine registered into this embedder
+func NumberOfEngines() C.int {
+	return C.int(len(flutterEngines))
+}
 
 // Result corresponds to the C.enum retuned by the shared flutter library
 // whenever we call it.
@@ -42,20 +52,20 @@ type EngineOpenGL struct {
 
 	// Engine arguments
 	PixelRatio  float64
-	AssetsPath  unsafe.Pointer
-	IcuDataPath unsafe.Pointer
+	AssetsPath  string
+	IcuDataPath string
 }
 
 // Run launches the Flutter Engine in a background thread.
 func (flu *EngineOpenGL) Run(window uintptr, vmArgs []string) Result {
 
-	globalFlutterOpenGL = *flu
+	flutterEngines = append(flutterEngines, flu)
 
 	args := C.FlutterProjectArgs{
-		assets_path:   (*C.char)(flu.AssetsPath),
+		assets_path:   C.CString(flu.AssetsPath),
 		main_path:     C.CString(""),
 		packages_path: C.CString(""),
-		icu_data_path: (*C.char)(flu.IcuDataPath),
+		icu_data_path: C.CString(flu.IcuDataPath),
 	}
 
 	args.struct_size = C.size_t(unsafe.Sizeof(args))
@@ -136,17 +146,24 @@ func (flu *EngineOpenGL) EngineSendWindowMetricsEvent(Metric WindowMetricsEvent)
 	return (Result)(res)
 }
 
-type platformMessageResponseHandle C.FlutterPlatformMessageResponseHandle
-
-// PlatformMessage represents a message from or to the Flutter Engine (and thus the dart code)
+// PlatformMessage represents a `MethodChannel` serialized with the `JSONMethodCodec`
+// TODO Support for `StandardMethodCodec`
 type PlatformMessage struct {
 	Channel        string
 	Message        Message
-	ResponseHandle *platformMessageResponseHandle
+	ResponseHandle *C.FlutterPlatformMessageResponseHandle
+}
+
+// Message is the json content of a PlatformMessage
+type Message struct {
+	// Describe the method
+	Method string `json:"method"`
+	// Actual datas
+	Args json.RawMessage `json:"args"`
 }
 
-// EngineSendPlatformMessage is used to send a PlatformMessage to the Flutter engine.
-func (flu *EngineOpenGL) EngineSendPlatformMessage(Message PlatformMessage) Result {
+// SendPlatformMessage is used to send a PlatformMessage to the Flutter engine.
+func (flu *EngineOpenGL) SendPlatformMessage(Message PlatformMessage) Result {
 
 	marshalled, err := json.Marshal(Message.Message)
 	if err != nil {
@@ -170,6 +187,22 @@ func (flu *EngineOpenGL) EngineSendPlatformMessage(Message PlatformMessage) Resu
 	return (Result)(res)
 }
 
+// SendPlatformMessageResponse is used to send a message to the Flutter side using the correct ResponseHandle!
+func (flu *EngineOpenGL) SendPlatformMessageResponse(
+	responseTo PlatformMessage,
+	data []byte,
+) Result {
+
+	res := C.FlutterEngineSendPlatformMessageResponse(
+		flu.Engine,
+		(*C.FlutterPlatformMessageResponseHandle)(responseTo.ResponseHandle),
+		(*C.uint8_t)(unsafe.Pointer(C.CBytes(data))),
+		(C.ulong)(len(data)))
+
+	return (Result)(res)
+
+}
+
 // EngineFlushPendingTasksNow flush tasks on a  message loop not controlled by the Flutter engine.
 // deprecated soon.
 func EngineFlushPendingTasksNow() {

flutter/flutter_helper.c

@@ -15,18 +15,18 @@ bool proxy_on_platform_message(FlutterPlatformMessage *message,
 
 // C helper
 FlutterResult runFlutter(uintptr_t window, FlutterEngine *engine, FlutterProjectArgs * Args,
-						 const char *const * vmArgs, int nVmAgrs) {
+												const char *const * vmArgs, int nVmAgrs) {
 
 	FlutterRendererConfig config = {};
 	config.type = kOpenGL;
 
 	config.open_gl.struct_size = sizeof(FlutterOpenGLRendererConfig);
 
-	config.open_gl.make_current = proxy_make_current;
-	config.open_gl.clear_current = proxy_clear_current;
-	config.open_gl.present = proxy_present;
-	config.open_gl.fbo_callback = proxy_fbo_callback;
-	config.open_gl.make_resource_current = proxy_make_resource_current;
+  config.open_gl.make_current = proxy_make_current;
+  config.open_gl.clear_current = proxy_clear_current;
+  config.open_gl.present = proxy_present;
+  config.open_gl.fbo_callback = proxy_fbo_callback;
+  config.open_gl.make_resource_current = proxy_make_resource_current;
 
 	Args->command_line_argc = nVmAgrs;
 	Args->command_line_argv = vmArgs;