Use cinterop with stub headers instead of Flutter cocoapod dependency

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## unreleased
 
+- Use cinterop with stub headers instead of Flutter cocoapod dependency
+
 ## v0.1.0-rc.3
 
 - Fix conflicts with same method names across different modules on iOS by prefixing method names

example/FlutterKmpExample.podspec

@@ -8,8 +8,8 @@ Pod::Spec.new do |spec|
     spec.summary                  = 'Shared Kotlin code for flutter-kmp example'
     spec.vendored_frameworks      = 'build/cocoapods/framework/flutterkmpexample.framework'
     spec.libraries                = 'c++'
-    spec.ios.deployment_target    = '11.0'
-    spec.dependency 'Flutter'
+                
+                
 
     if !Dir.exist?('build/cocoapods/framework/flutterkmpexample.framework') || Dir.empty?('build/cocoapods/framework/flutterkmpexample.framework')
         raise "

example/build.gradle.kts

@@ -33,16 +33,11 @@ kotlin {
             homepage = "https://github.com/voize-gmbh/flutter-kmp"
             summary = "Shared Kotlin code for flutter-kmp example"
             baseName = "flutterkmpexample"
-        }
-
-        // We can not use a specific version here, because the podspec generated by this KMP project
-        // will be referenced by the Flutter plugin podspec and therefore the Flutter target app.
-        // The target app also depends on Flutter but the Flutter.podspec it uses has a stub version (1.0.0).
-        // So specifying a version here will create a conflict and instead we have to rely on the assumption
-        // that the interop for the Flutter in the Cocoapods registry is compatible with the Flutter version used in the target app.
-        pod("Flutter")
 
-        ios.deploymentTarget = "11.0"
+            // without setting the framework to static, you will get errors during linking
+            // that symbols e.g. for _OBJC_CLASS_$_FlutterError are missing
+            isStatic = true
+        }
     }
 
     sourceSets {

flutter-kmp-ksp/src/main/kotlin/de/voize/flutterkmp/ksp/processor/IOSKotlinModuleGenerator.kt

@@ -138,11 +138,11 @@ class IOSKotlinModuleGenerator {
 private val ExperimentalForeignApi = ClassName("kotlinx.cinterop", "ExperimentalForeignApi")
 private val NSObject = ClassName("platform.darwin", "NSObject")
 
-private val FlutterResult = ClassName("cocoapods.Flutter", "FlutterResult")
-private val FlutterMethodCall = ClassName("cocoapods.Flutter", "FlutterMethodCall")
-private val FlutterMethodChannel = ClassName("cocoapods.Flutter", "FlutterMethodChannel")
-private val FlutterEventChannel = ClassName("cocoapods.Flutter", "FlutterEventChannel")
-private val FlutterPluginRegistrar = ClassName("cocoapods.Flutter", "FlutterPluginRegistrarProtocol")
-private val FlutterPlugin = ClassName("cocoapods.Flutter", "FlutterPluginProtocol")
-private val FlutterStandardMethodCodec = ClassName("cocoapods.Flutter", "FlutterStandardMethodCodec")
+private val FlutterResult = ClassName("flutter", "FlutterResult")
+private val FlutterMethodCall = ClassName("flutter", "FlutterMethodCall")
+private val FlutterMethodChannel = ClassName("flutter", "FlutterMethodChannel")
+private val FlutterEventChannel = ClassName("flutter", "FlutterEventChannel")
+private val FlutterPluginRegistrar = ClassName("flutter", "FlutterPluginRegistrarProtocol")
+private val FlutterPlugin = ClassName("flutter", "FlutterPluginProtocol")
+private val FlutterStandardMethodCodec = ClassName("flutter", "FlutterStandardMethodCodec")
 private val toEventStreamHandler = MemberName(flutterKmpPackageName, "toEventStreamHandler")

flutter-kmp/build.gradle.kts

@@ -1,7 +1,8 @@
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
+
 plugins {
     kotlin("multiplatform")
     kotlin("plugin.serialization")
-    kotlin("native.cocoapods")
     id("com.android.library")
 }
 
@@ -30,21 +31,18 @@ kotlin {
         publishLibraryVariants("release")
     }
 
-    cocoapods {
-        // this cocoapods dependency is needed for the iOS EventStreamHandler utils
-        pod("Flutter")
-
-        // we do not need to create a podspec file because the KMP projects that use this library 
-        // must produce a podspec that contains the Flutter cocoapod dependency
-        noPodspec()
-
-        ios.deploymentTarget = "11.0"
+    fun KotlinNativeTarget.configureFlutterInterop() {
+        val main by compilations.getting {
+            val flutter by cinterops.creating {
+                includeDirs("src/nativeInterop/cinterop/")
+                packageName("flutter")
+            }
+        }
     }
 
-
-    iosX64()
-    iosArm64()
-    iosSimulatorArm64()
+    iosX64 { configureFlutterInterop() }
+    iosArm64 { configureFlutterInterop() }
+    iosSimulatorArm64 { configureFlutterInterop() }
     wasmJs { nodejs() }
 
     applyDefaultHierarchyTemplate()

flutter-kmp/src/iosMain/kotlin/EventStreamHandlerUtils.kt

@@ -1,9 +1,6 @@
 package de.voize.flutterkmp
 
-import cocoapods.Flutter.FlutterError
-import cocoapods.Flutter.FlutterEventSink
 import kotlinx.coroutines.flow.Flow
-import cocoapods.Flutter.FlutterStreamHandlerProtocol
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
@@ -12,7 +9,9 @@ import kotlinx.coroutines.withContext
 import kotlinx.serialization.SerializationStrategy
 import kotlinx.serialization.serializer
 import platform.darwin.NSObject
-
+import flutter.FlutterStreamHandlerProtocol
+import flutter.FlutterEventSink
+import flutter.FlutterError
 
 inline fun <reified T> Flow<T>.toEventStreamHandler(): NSObject =
     toEventStreamHandler(serializer<T>())
@@ -45,4 +44,4 @@ fun <T> Flow<T>.toEventStreamHandler(serializer: SerializationStrategy<T>): NSOb
             return null
         }
     }
-}
+}

flutter-kmp/src/nativeInterop/cinterop/Flutter/FlutterPlugin.h

@@ -0,0 +1,74 @@
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/ios/framework/Headers/FlutterPlugin.h
+
+#import <Foundation/Foundation.h>
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterBinaryMessenger.h#L49C1-L49C44
+@protocol FlutterBinaryMessenger <NSObject>
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterChannels.h#L194
+typedef void (^FlutterResult)(id _Nullable result);
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h#L391
+@protocol FlutterMethodCodec
++ (instancetype)sharedInstance;
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h#L18C1-L18C30
+@protocol FlutterMessageCodec
++ (instancetype)sharedInstance;
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterChannels.h#L220
+@interface FlutterMethodChannel : NSObject
+- (instancetype)initWithName:(NSString*)name
+             binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
+                       codec:(NSObject<FlutterMessageCodec>*)codec;
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterChannels.h#L350
+typedef void (^FlutterEventSink)(id _Nullable event);
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h#L246C1-L246C35
+@interface FlutterError : NSObject
++ (instancetype)errorWithCode:(NSString*)code
+                      message:(NSString* _Nullable)message
+                      details:(id _Nullable)details;
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterChannels.h#L356
+@protocol FlutterStreamHandler <NSObject>
+- (FlutterError* _Nullable)onListenWithArguments:(id _Nullable)arguments
+                                       eventSink:(FlutterEventSink)events;
+- (FlutterError* _Nullable)onCancelWithArguments:(id _Nullable)arguments;
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterChannels.h#L400C1-L400C42
+@interface FlutterEventChannel : NSObject
+- (instancetype)initWithName:(NSString*)name
+             binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger
+                       codec:(NSObject<FlutterMethodCodec>*)codec;
+- (void)setStreamHandler:(NSObject<FlutterStreamHandler>* _Nullable)handler;
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/ios/framework/Headers/FlutterPlugin.h#L189
+@protocol FlutterPlugin <NSObject>
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/ios/framework/Headers/FlutterPlugin.h#L283
+@protocol FlutterPluginRegistrar <NSObject>
+- (NSObject<FlutterBinaryMessenger>*)messenger;
+- (void)addMethodCallDelegate:(NSObject<FlutterPlugin>*)delegate
+        channel:(FlutterMethodChannel*)channel;
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h#L220
+@interface FlutterMethodCall : NSObject
+@property(readonly, nonatomic) NSString* method;
+@property(readonly, nonatomic, nullable) id arguments;
+@end
+
+// https://github.com/flutter/engine/blob/3.22.2/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h#L469
+@interface FlutterStandardMethodCodec : NSObject <FlutterMethodCodec>
+@end

flutter-kmp/src/nativeInterop/cinterop/flutter.def

@@ -0,0 +1,3 @@
+language = Objective-C
+headers = Flutter/FlutterPlugin.h
+headerFilter = Flutter/*