USSDService

package velasolutions.velabank.services

import android.accessibilityservice.AccessibilityService
import android.accessibilityservice.AccessibilityServiceInfo
import android.content.Context
import android.graphics.PixelFormat
import android.os.Build
import android.util.Log
import android.view.Gravity
import android.view.LayoutInflater
import android.view.View
import android.view.WindowManager
import android.view.accessibility.AccessibilityEvent

import org.greenrobot.eventbus.EventBus
import timber.log.Timber
import velasolutions.velabank.R

import velasolutions.velabank.events.VelaBankEvent
import velasolutions.velabank.persistence.Session

class VelaBankAccessibilityService : AccessibilityService() {
    private var overlay: View? = null
    private lateinit var windowManager: WindowManager
    private var overlayDrawn: Boolean = false

    override fun onCreate() {
        super.onCreate()
        windowManager = getSystemService(Context.WINDOW_SERVICE) as WindowManager
    }

    override fun onAccessibilityEvent(event: AccessibilityEvent?) {
        Timber.d("On Event: $event")
        //get the text for subsequent events, which are events of interest
        val ussdResponse = event?.text.toString()
        closePopupDialog()

        if (event == null) {
            return
        }
        if ((event.eventType == AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED
                        || event.eventType == AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED) &&
                (!event.packageName.contains("com.android.phone") ||
                        !event.packageName.contains("com.android.phone"))) {
            return
        }

        val className = event.className
        if (className.contains("ProgressDialog")) {
            //The first event that has "ProgressDialog" as class name has been fired.
            //attach the window overlay at this point
            addOverlay()
        }

        if (className.contains("FrameLayout")) {
            removeOverlay()
        }
        //check if the second event is fired.
        if (className.contains("AlertDialog")) {
            removeOverlay()
            val velaBankEvent = VelaBankEvent(ussdResponse, Session.getInstance().getMenuServiceCode())
            EventBus.getDefault().post(velaBankEvent)
        }
    }

    private fun closePopupDialog() {
        performGlobalAction(AccessibilityService.GLOBAL_ACTION_BACK)
    }

    override fun onInterrupt() {
        Timber.d("onServiceInterrupted")
    }

    public override fun onServiceConnected() {
        super.onServiceConnected()
        Timber.d("onServiceConnected")
        val info = AccessibilityServiceInfo()
        info.flags = AccessibilityServiceInfo.DEFAULT
        info.packageNames = arrayOf("com.android.phone", "com.android.app")
        info.eventTypes = AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED or AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED
        info.feedbackType = AccessibilityServiceInfo.FEEDBACK_GENERIC
        serviceInfo = info
    }

    private fun addOverlay() {
        val params = WindowManager.LayoutParams(
                WindowManager.LayoutParams.MATCH_PARENT,
                WindowManager.LayoutParams.MATCH_PARENT,
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                    WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY
                } else {
                    WindowManager.LayoutParams.TYPE_SYSTEM_ALERT
                },
                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
                PixelFormat.OPAQUE)

        params.gravity = Gravity.CENTER
        overlay = LayoutInflater.from(this).inflate(R.layout.ussd_alert_overlay, null)
        windowManager.addView(overlay, params)
        overlayDrawn = true
    }

    private fun removeOverlay() {
        if (overlayDrawn && overlay != null) {
            try {
                windowManager.removeView(overlay)
                overlayDrawn = false
            } catch (e: IllegalArgumentException) {
                e.printStackTrace()
            }
        }
    }

    companion object {
        const val TAG = "AccessibilityService"
        fun getTAG(): String {
            return TAG
        }
    }
}

xml file
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/gray">


    <android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="8dp"
        android:padding="@dimen/fab_margin"
        app:cardElevation="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <ProgressBar
            android:id="@+id/progressBar"
            style="?android:attr/progressBarStyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_margin="48dp" />
    </android.support.v7.widget.CardView>
</android.support.constraint.ConstraintLayout>