fix(v3): restore Android build and runtime message handling

Fixes five regressions in Android support:

1. Restore events.Android struct (IDs 1259-1270) and JS event mappings
   that were removed from events.go, breaking events_common_android.go
2. Pass flags to runtime.Core() in nativeOnPageFinished to match the
   updated API signature used by all other platforms
3. Call setupCommonEvents() in the CGO build's run() method (the
   non-CGO build already did this)
4. Replace the stub handleMessageForAndroid() with real MessageProcessor
   routing so JS-to-Go runtime calls (bound methods, clipboard, etc.)
   actually work
5. Handle non-JSON string messages (e.g. "wails:runtime:ready") that
   the JS bridge sends before attempting JSON parse

Fixes #5020

Co-authored-by: Varun Chawla <varun_6april@hotmail.com>

v3/pkg/application/application_android.go

@@ -139,8 +139,11 @@ static void executeJavaScriptOnBridge(const char* js) {
 import "C"
 
 import (
+	"context"
+	"encoding/json"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -148,8 +151,6 @@ import (
 	"time"
 	"unsafe"
 
-	"encoding/json"
-
 	"github.com/wailsapp/wails/v3/internal/runtime"
 )
 
@@ -221,6 +222,12 @@ func (a *App) platformRun() {
 	globalApp = a
 	globalAppLock.Unlock()
 
+	// Create MessageProcessor so JNI message callbacks can route runtime calls
+	messageProc := NewMessageProcessor(slog.Default())
+	globalMessageProcLock.Lock()
+	globalMessageProc = messageProc
+	globalMessageProcLock.Unlock()
+
 	// Signal that the app is ready to serve requests
 	signalAppReady()
 
@@ -259,6 +266,9 @@ func newPlatformApp(app *App) *androidApp {
 func (a *androidApp) run() error {
 	androidLogf("info", "🤖 [application_android.go] androidApp.run() called")
 
+	// Wire platform events → common events (same as non-CGO build)
+	a.setupCommonEvents()
+
 	// Emit application started event
 	a.parent.Event.Emit("ApplicationStarted")
 
@@ -433,7 +443,7 @@ func Java_com_wails_app_WailsBridge_nativeOnPageFinished(env *C.JNIEnv, obj C.jo
 		if win != nil {
 			androidLogf("info", "🤖 [JNI] Injecting runtime.Core() into window %d", id)
 			// Get the runtime core JavaScript
-			runtimeJS := runtime.Core()
+			runtimeJS := runtime.Core(app.impl.GetFlags(app.options))
 			androidLogf("info", "🤖 [JNI] Runtime JS length: %d bytes", len(runtimeJS))
 			app.windowsLock.RUnlock()
 			// IMPORTANT: We must bypass win.ExecJS because it queues if runtimeLoaded is false.
@@ -621,16 +631,60 @@ func serveAssetForAndroid(app *App, path string) ([]byte, error) {
 	return body, nil
 }
 
+// Global MessageProcessor for Android JNI callbacks
+var (
+	globalMessageProc     *MessageProcessor
+	globalMessageProcLock sync.RWMutex
+)
+
 func handleMessageForAndroid(app *App, message string) string {
-	// Parse the message
+	// Some messages are plain strings (e.g. "wails:runtime:ready"), not JSON.
-	var msg map[string]interface{}
+	// The JS bridge sends: typeof m==='string' ? m : JSON.stringify(m)
-	if err := json.Unmarshal([]byte(message), &msg); err != nil {
+	if len(message) == 0 || message[0] != '{' {
+		androidLogf("debug", "🤖 [handleMessageForAndroid] Non-JSON message: %s", message)
+		return `{"success":true}`
+	}
+
+	var req RuntimeRequest
+	if err := json.Unmarshal([]byte(message), &req); err != nil {
+		androidLogf("error", "🤖 [handleMessageForAndroid] Failed to parse: %v", err)
 		return fmt.Sprintf(`{"error":"%s"}`, err.Error())
 	}
 
-	// TODO: Route to appropriate handler based on message type
+	// Fill in a window ID if none was provided (Android typically has one window)
-	// For now, return success
+	if req.WebviewWindowID == 0 && req.WebviewWindowName == "" {
-	return `{"success":true}`
+		windows := app.Window.GetAll()
+		if len(windows) > 0 {
+			req.WebviewWindowID = uint32(windows[0].ID())
+		}
+	}
+
+	globalMessageProcLock.RLock()
+	messageProc := globalMessageProc
+	globalMessageProcLock.RUnlock()
+
+	if messageProc == nil {
+		androidLogf("error", "🤖 [handleMessageForAndroid] MessageProcessor not initialized")
+		return `{"error":"MessageProcessor not initialized"}`
+	}
+
+	ctx := context.Background()
+	result, err := messageProc.HandleRuntimeCallWithIDs(ctx, &req)
+	if err != nil {
+		androidLogf("error", "🤖 [handleMessageForAndroid] Error: %v", err)
+		return fmt.Sprintf(`{"error":"%s"}`, err.Error())
+	}
+
+	if result == nil {
+		return `{"success":true}`
+	}
+
+	resp, err := json.Marshal(result)
+	if err != nil {
+		androidLogf("error", "🤖 [handleMessageForAndroid] Marshal error: %v", err)
+		return fmt.Sprintf(`{"error":"%s"}`, err.Error())
+	}
+	return string(resp)
 }
 
 func getMimeTypeForPath(path string) string {

v3/pkg/application/application_android_nocgo.go

@@ -3,11 +3,12 @@
 package application
 
 import (
+	"context"
+	"encoding/json"
 	"fmt"
+	"log/slog"
 	"sync"
 	"unsafe"
-
-	"encoding/json"
 )
 
 var (
@@ -38,6 +39,12 @@ func (a *App) platformRun() {
 	globalApp = a
 	globalAppLock.Unlock()
 
+	// Create MessageProcessor so message callbacks can route runtime calls
+	messageProc := NewMessageProcessor(slog.Default())
+	globalMessageProcLock.Lock()
+	globalMessageProc = messageProc
+	globalMessageProcLock.Unlock()
+
 	androidLogf("info", "🤖 [application_android.go] Waiting for Android lifecycle...")
 
 	// Block forever - Android manages the app lifecycle via JNI callbacks
@@ -171,16 +178,58 @@ func serveAssetForAndroid(app *App, path string) ([]byte, error) {
 	return nil, fmt.Errorf("asset serving not yet implemented: %s", path)
 }
 
+// Global MessageProcessor for message callbacks
+var (
+	globalMessageProc     *MessageProcessor
+	globalMessageProcLock sync.RWMutex
+)
+
 func handleMessageForAndroid(app *App, message string) string {
-	// Parse the message
+	// Some messages are plain strings (e.g. "wails:runtime:ready"), not JSON.
-	var msg map[string]interface{}
+	if len(message) == 0 || message[0] != '{' {
-	if err := json.Unmarshal([]byte(message), &msg); err != nil {
+		androidLogf("debug", "🤖 [handleMessageForAndroid] Non-JSON message: %s", message)
+		return `{"success":true}`
+	}
+
+	var req RuntimeRequest
+	if err := json.Unmarshal([]byte(message), &req); err != nil {
+		androidLogf("error", "🤖 [handleMessageForAndroid] Failed to parse: %v", err)
 		return fmt.Sprintf(`{"error":"%s"}`, err.Error())
 	}
 
-	// TODO: Route to appropriate handler based on message type
+	if req.WebviewWindowID == 0 && req.WebviewWindowName == "" {
-	// For now, return success
+		windows := app.Window.GetAll()
-	return `{"success":true}`
+		if len(windows) > 0 {
+			req.WebviewWindowID = uint32(windows[0].ID())
+		}
+	}
+
+	globalMessageProcLock.RLock()
+	messageProc := globalMessageProc
+	globalMessageProcLock.RUnlock()
+
+	if messageProc == nil {
+		androidLogf("error", "🤖 [handleMessageForAndroid] MessageProcessor not initialized")
+		return `{"error":"MessageProcessor not initialized"}`
+	}
+
+	ctx := context.Background()
+	result, err := messageProc.HandleRuntimeCallWithIDs(ctx, &req)
+	if err != nil {
+		androidLogf("error", "🤖 [handleMessageForAndroid] Error: %v", err)
+		return fmt.Sprintf(`{"error":"%s"}`, err.Error())
+	}
+
+	if result == nil {
+		return `{"success":true}`
+	}
+
+	resp, err := json.Marshal(result)
+	if err != nil {
+		androidLogf("error", "🤖 [handleMessageForAndroid] Marshal error: %v", err)
+		return fmt.Sprintf(`{"error":"%s"}`, err.Error())
+	}
+	return string(resp)
 }
 
 func getMimeTypeForPath(path string) string {

v3/pkg/events/events.go

@@ -523,6 +523,40 @@ func newIOSEvents() iosEvents {
 	}
 }
 
+var Android = newAndroidEvents()
+
+type androidEvents struct {
+	ActivityCreated          ApplicationEventType
+	ActivityStarted          ApplicationEventType
+	ActivityResumed          ApplicationEventType
+	ActivityPaused           ApplicationEventType
+	ActivityStopped          ApplicationEventType
+	ActivityDestroyed        ApplicationEventType
+	ApplicationLowMemory     ApplicationEventType
+	ApplicationConfigChanged ApplicationEventType
+	WebViewDidStartNavigation  WindowEventType
+	WebViewDidFinishNavigation WindowEventType
+	WebViewDidFailNavigation   WindowEventType
+	WebViewReceivedError       WindowEventType
+}
+
+func newAndroidEvents() androidEvents {
+	return androidEvents{
+		ActivityCreated:            1259,
+		ActivityStarted:            1260,
+		ActivityResumed:            1261,
+		ActivityPaused:             1262,
+		ActivityStopped:            1263,
+		ActivityDestroyed:          1264,
+		ApplicationLowMemory:       1265,
+		ApplicationConfigChanged:   1266,
+		WebViewDidStartNavigation:  1267,
+		WebViewDidFinishNavigation: 1268,
+		WebViewDidFailNavigation:   1269,
+		WebViewReceivedError:       1270,
+	}
+}
+
 func JSEvent(event uint) string {
 	return eventToJS[event]
 }
@@ -763,4 +797,16 @@ var eventToJS = map[uint]string{
 	1256: "ios:WebViewDidFinishNavigation",
 	1257: "ios:WebViewDidFailNavigation",
 	1258: "ios:WebViewDecidePolicyForNavigationAction",
+	1259: "android:ActivityCreated",
+	1260: "android:ActivityStarted",
+	1261: "android:ActivityResumed",
+	1262: "android:ActivityPaused",
+	1263: "android:ActivityStopped",
+	1264: "android:ActivityDestroyed",
+	1265: "android:ApplicationLowMemory",
+	1266: "android:ApplicationConfigChanged",
+	1267: "android:WebViewDidStartNavigation",
+	1268: "android:WebViewDidFinishNavigation",
+	1269: "android:WebViewDidFailNavigation",
+	1270: "android:WebViewReceivedError",
 }