How can i inject xamarin smali code into another apk?

Question

I tried to make a simple foreground service android application using xamarin... then decompile and inject it into another apk...but it always crashes.

here is adb logcat :

05-31 23:57:34.158  7680  7680 W Activity: Slow Operation: Activity com.injected.app/org.injected.cpp.AppActivity onCreate took 1440ms
05-31 23:57:34.169  7680  7680 D injectedActivity: onResume()
05-31 23:57:34.172  7680  7680 W AudioManager: Use of stream types is deprecated for operations other than volume control
05-31 23:57:34.172 7680  7680 W AudioManager: See the documentation of requestAudioFocus() for what to use instead with android.media.AudioAttributes to qualify your playback use case
05-31 23:57:34.180  7680  7680 D AudioFocusManager: requestAudioFocus succeed
05-31 23:57:34.190  7436  7465 I ui.cloudservic: ProcessProfilingInfo new_methods=0 is saved saved_to_disk=0 resolve_classes_delay=8000
05-31 23:57:34.196  7680  8021 I DpmTcmClient: RegisterTcmMonitor from: $Proxy0
05-31 23:57:34.202  1617  4424 E WindowManager: App trying to use insecure INPUT_FEATURE_NO_INPUT_CHANNEL flag. Ignoring
05-31 23:57:34.208  7680 7680 W Looper  : PerfMonitor longMsg : seq=3 plan=23:57:32.356 late=338ms wall=1514ms running=916ms runnable=174ms io=223ms h=android.app.ActivityThread$H w=159 procState=2
05-31 23:57:34.208  7680  7680 W Looper  : PerfMonitor looperActivity : package=com.injected.app/org.injected.cpp.AppActivity time=1514ms latency=338ms running=916ms  procState=2 ClientTransaction{ callbacks=[android.app.servertransaction.LaunchActivityItem] lifecycleRequest=android.app.servertransaction.ResumeActivityItem } historyMsgCount=2 (msgIndex=2 wall=327ms seq=2 running=05ms runnable=83ms io=8ms late=20ms h=android.app.ActivityThread$H w=110)
05-31 23:57:34.227 28 05 28517 W ocessService0:: Reducing the number of considered missed Gc histogram windows from 162 to 100
05-31 23:57:34.232  7680  7680 W Looper  : PerfMonitor looperActivity : package=com.injected.app/org.injected.cpp.AppActivity time=0ms latency=1875ms running=0ms  procState=2 ClientTransaction{ callbacks=[android.app.servertransaction.TopResumedActivityChangeItem] } historyMsgCount=3 (msgIndex=2 wall=327ms seq=2 running=05ms runnable=83ms io=8ms late=20ms h=android.app.ActivityThread$H w=110) (msgIndex=3 wall=1514ms seq=3 running=916ms runnable=174ms io=223ms late=338ms h=android.app.ActivityThread$H w=159)
05-31 23:57:34.233  7711  8033 I SecurityDevice: getService: sService == null. 
05-31 23:57:34.233  7711  8033 W SecurityDevice: getService: binder not alive. 
05-31 23:57:34.234  7680  7680 E m.injected.app: No implementation found for void mono.android.Runtime.register(java.lang.String, java.lang.Class, java.lang.String) (tried Java_mono_android_Runtime_register and Java_mono_android_Runtime_register__Ljava_lang_String_2Ljava_lang_Class_2Ljava_lang_String_2)
05-31 23:57:34.241  7680  7680 D AndroidRuntime: Shutting down VM
05-31 23:57:34.242  7680  7680 E AndroidRuntime: FATAL EXCEPTION: main
05-31 23:57:34.242  7680  7680 E AndroidRuntime: Process: com.injected.app, PID: 7680
05-31 23:57:34.242  7680  7680 E AndroidRuntime: java.lang.UnsatisfiedLinkError: No implementation found for void mono.android.Runtime.register(java.lang.String, java.lang.Class, java.lang.String) (tried Java_mono_android_Runtime_register and Java_mono_android_Runtime_register__Ljava_lang_String_2Ljava_lang_Class_2Ljava_lang_String_2)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at mono.android.Runtime.register(Native Method)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at crc6464567c73758a9f18.MainService.<clinit>(MainService.java:18)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at java.lang.Class.newInstance(Native Method)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at android.app.AppComponentFactory.instantiateService(AppComponentFactory.java:129)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at androidx.core.app.CoreComponentFactory.instantiateService(CoreComponentFactory.java:75)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at android.app.ActivityThread.handleCreateService(ActivityThread.java:4013)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at android.app.ActivityThread.access$1600(ActivityThread.java:229)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1917)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at android.os.Handler.dispatchMessage(Handler.java:107)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at android.os.Looper.loop(Looper.java:226)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at android.app.ActivityThread.main(ActivityThread.java:7592)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at java.lang.reflect.Method.invoke(Native Method)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
05-31 23:57:34.242  7680  7680 E AndroidRuntime:    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
05-31 23:57:34.249  3690 14633 I CryptauthV2: [EnrollCryptauthFramework] SyncKeysRequest successfully completed
05-31 23:57:34.251   634  8029 E ResolverController: No valid NAT64 prefix (109, <unspecified>/0)
05-31 23:57:34.263  7974  7974 I FeatureParser: can't find citrus.xml in assets/device_features/,it may be in /vendor/etc/device_features
05-31 23:57:34.266  7680  7680 D OOMEventManagerFK: checkEventAndDumpForJE: 0
05-31 23:57:34.266  7974  7974 I SpaceUtils: owner space
05-31 23:57:34.267  7680  7680 E m.injected.app: No implementation found for void mono.android.Runtime.propagateUncaughtException(java.lang.Thread, java.lang.Throwable) (tried Java_mono_android_Runtime_propagateUncaughtException and Java_mono_android_Runtime_propagateUncaughtException__Ljava_lang_Thread_2Ljava_lang_Throwable_2)
05-31 23:57:34.284  7680  7680 I m.injected.app: Waiting for a blocking GC ProfileSaver
05-31 23:57:34.314  7680  7680 I m.injected.app: WaitForGcToComplete blocked ProfileSaver on ClassLinker for 30.622ms