UssdAccessibilityService.java

@Override
public void onAccessibilityEvent(AccessibilityEvent event) {
    final String messageViewId = "android:id/message";
    final String buttonViewId = "android:id/button1";

    // get root layout node of dialog
    AccessibilityNodeInfo rootNode = event.getSource();

    // find textview with message & button nodes
    List<AccessibilityNodeInfo> ussdResponseTextViewNodesList =
        rootNode.findAccessibilityNodeInfosByViewId(messageViewId);
    
    List<AccessibilityNodeInfo> cancelButtonNodesList =
        rootNode.findAccessibilityNodeInfosByViewId(buttonViewId);

    // if dialog doesn't contain views - skip accessibility event
    if (ussdResponseTextViewNodesList.isEmpty() || cancelButtonNodesList.isEmpty()) {
        return;
    }

    // get text from textview
    CharSequence ussdReponse = ussdResponseTextViewNodesList.get(0).getText();

    // store ussd response and notify activity
    App.INSTANCE.ussdExecutor.setResponse(ussdReponse.toString());
    App.INSTANCE.eventBus.sendEvent(EventBus.Event.USSD_RESULT_RECEIVED);

    // dismiss dialog
    cancelButtonNodesList.get(0).performAction(AccessibilityNodeInfo.ACTION_CLICK);
}