我无法进入主活动观察功能

Question

我有一个在授予权限时触发的服务类（AccessibilityService）。我检查在 onAccessibilityEvent() 方法中所做的窗口更改并将包名称发送到视图模型，然后我尝试在 MainActivity 中观察我的 LiveData 对象以在 UI 中显示它，但我无法进入观察功能

class ServiceAccess : AccessibilityService() {
    private val TAG = "ServiceAccess"

    override fun onAccessibilityEvent(event: AccessibilityEvent?) {
        Log.d(TAG, "AccesibilityEvent gerçekleşti")
        val packageName: String = event?.packageName.toString()
        val packageManager = applicationContext.packageManager

        val viewModel = ViewModelProvider.AndroidViewModelFactory.getInstance(application).create(PackageViewModel::class.java)

        val applicationInfo: ApplicationInfo = packageManager.getApplicationInfo(packageName, 0)
        val applicationLabel = packageManager.getApplicationLabel(applicationInfo)
        Log.d(TAG, "app name :$applicationLabel")

        if (event != null) {
            if (AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED == event.eventType) {
                if (event.packageName != null && event.className != null) {
                    viewModel.setRunningPackageNames(event)
                    Log.d(TAG, "runn app: " + event.packageName.toString())
                }
            }

        }
    }


    override fun onInterrupt() {
        Log.d(TAG, "error!!")
    }

    override fun onServiceConnected() {
        super.onServiceConnected()
        val info = AccessibilityServiceInfo()

        info.apply {
            eventTypes =
                AccessibilityEvent.TYPE_VIEW_CLICKED or AccessibilityEvent.TYPE_VIEW_FOCUSED or AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED
            feedbackType = AccessibilityServiceInfo.FEEDBACK_SPOKEN
            notificationTimeout = 100
        }
        this.serviceInfo = info
        Log.d(TAG, "connection")
    }


}

class PackageViewModel : ViewModel() {
    private val TAG = "PackageViewModel"
    private val _currentPackageName =MutableLiveData<NamePackage>()
    val currentPackageName: LiveData<NamePackage>
        get() = _currentPackageName

    fun setRunningPackageNames(event: AccessibilityEvent) {
        val eventData = NamePackage(currentPackageName = event.packageName.toString())
        _currentPackageName.value = eventData
        Log.d(TAG, "viewModel :${currentPackageName.value}")

    }



}

class MainActivity : AppCompatActivity() {
    private lateinit var binding: ActivityMainBinding
    private lateinit var packageViewModel: PackageViewModel
    private val TAG = "MainActivityObserve"

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        val accessibilityManager =
            getSystemService(Context.ACCESSIBILITY_SERVICE) as AccessibilityManager
        val isAccessibilityEnabled = accessibilityManager.isEnabled

        packageViewModel = ViewModelProvider(this).get(PackageViewModel::class.java)

        if (!isAccessibilityEnabled) { 
            openAccessibilitySettings()
        }

        packageViewModel.currentPackageName.observe(this, Observer { packageName ->
            Log.d(TAG, "mainActivty: $packageName")
        })
    }

    private fun openAccessibilitySettings() {
        val intent = Intent(Settings.ACTION_ACCESSIBILITY_SETTINGS)
        startActivity(intent)
    }

}