feat: instantiate channel and return to go

android/NotificationHelper.java

@@ -1,5 +1,6 @@
 package ht.sr.git.whereswaldon.niotify;
 
+import android.content.Context;
 import android.app.Notification;
 import android.app.NotificationChannel;
 import android.app.NotificationManager;
@@ -8,7 +9,20 @@ import android.graphics.Bitmap;
 import android.graphics.drawable.Icon;
 
 public class NotificationHelper {
-    public static void newChannel() {
+    public static NotificationChannel newChannel(Context ctx) {
-        Log.w("NotificationHelper",String.format("newChannel invoked"));
+        String tag = "NotificationHelper";
+        Log.w(tag,String.format("newChannel invoked"));
+        String CHANNEL_ID = "CHANNEL_ID";
+        CharSequence name = "notification_channel_name";
+        String description = "notification_channel_description";
+        int importance = NotificationManager.IMPORTANCE_DEFAULT;
+        NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);
+    	Log.e(tag,String.format("channel: %s",channel));
+        channel.setDescription(description);
+
+        NotificationManager notificationManager = ctx.getSystemService(NotificationManager.class);
+    	Log.e(tag,String.format("manager: %s",notificationManager));
+        notificationManager.createNotificationChannel(channel);
+        return channel;
     }
 }

android/notify_android.go

@@ -2,27 +2,45 @@ package android
 
 import (
 	"fmt"
+	"runtime"
 
 	"gioui.org/app"
 	"github.com/tailscale/tailscale-android/jni"
 )
 
 type NotificationChannel struct {
+	javaObj jni.Object
 }
 
-func NewChannel(jvm uintptr, name, description string) (*NotificationChannel, error) {
+func NewChannel(name, description string) (*NotificationChannel, error) {
-	if err := jni.Do(jni.JVMFor(jvm), func(env jni.Env) error {
+	var channel jni.Object
-		classLoader := jni.ClassLoaderFor(env, jni.Object(app.AppContext()))
+	if err := jni.Do(jni.JVMFor(app.JavaVM()), func(env jni.Env) error {
+		appCtx := jni.Object(app.AppContext())
+		classLoader := jni.ClassLoaderFor(env, appCtx)
 		notifyClass, err := jni.LoadClass(env, classLoader, "ht/sr/git/whereswaldon/niotify/NotificationHelper")
 		if err != nil {
 			return err
 		}
-		newChannelMethod := jni.GetStaticMethodID(env, notifyClass, "newChannel", "()V")
+		newChannelMethod := jni.GetStaticMethodID(env, notifyClass, "newChannel", "(Landroid/content/Context;)Landroid/app/NotificationChannel;")
-		jname := jni.Value(jni.JavaString(env, name))
+		// jname := jni.Value(jni.JavaString(env, name))
-		jdescription := jni.Value(jni.JavaString(env, description))
+		// jdescription := jni.Value(jni.JavaString(env, description))
-		return jni.CallStaticVoidMethod(env, notifyClass, newChannelMethod, jname, jdescription)
+		channel, err = jni.CallStaticObjectMethod(env, notifyClass, newChannelMethod, jni.Value(app.AppContext()))
+		if err != nil {
+			return err
+		}
+		channel = jni.NewGlobalRef(env, channel)
+		return nil
 	}); err != nil {
 		return nil, fmt.Errorf("failed creating notification channel: %w", err)
 	}
-	return &NotificationChannel{}, nil
+	nc := &NotificationChannel{
+		javaObj: channel,
+	}
+	runtime.SetFinalizer(nc, func(obj *NotificationChannel) {
+		_ = jni.Do(jni.JVMFor(app.JavaVM()), func(env jni.Env) error {
+			jni.DeleteGlobalRef(env, obj.javaObj)
+			return nil
+		})
+	})
+	return nc, nil
 }

example/hello.go

@@ -31,7 +31,7 @@ func main() {
 		}
 	}()
 	go func() {
-		channel, err := android.NewChannel(app.JavaVM(), "hello", "description")
+		channel, err := android.NewChannel("hello", "description")
 		if err != nil {
 			log.Printf("channel creation failed: %v", err)
 		}