Answering a Whatsapp video call programmatically

Question

Is there a way to auto answer whatsapp video call using AccessibilityService in Android?

OR is there a way to stimulate a click on headset's/bluetooth's call answering button? How can i get the id of the answering button?? to perform a click with accessibility service

I know that starting from Android 8.0 Oreo we have ANSWER_PHONE_CALLS permission, but for my project i want to use an old device for remote monitoring.

Any help would be appreciated!

----- Update: Thanks to the answer of Mr. hemisphire and Mr. Kahbazi, the app is able to answer the call,but needs to be a system app to work! is there any way to make it work without being a system app? without the headset's button hack?

public class AnswerCall  extends AccessibilityService {
    @Override
    public void onAccessibilityEvent( AccessibilityEvent event )
    {
        if(event.getEventType() == TYPE_WINDOW_CONTENT_CHANGED)
        {

            if(event.getPackageName().equals("com.whatsapp"))
            {

                Thread thread = new Thread() {
                    @Override
                    public void run() {
                        try {
                            while(true) {
                                Instrumentation inst = new Instrumentation();
                                inst.sendKeyDownUpSync(KeyEvent.KEYCODE_HEADSETHOOK);
                            }
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                };

                thread.start();
                StringBuilder sb = new StringBuilder();
                List<CharSequence> texts = event.getText();
                if (!texts.isEmpty())
                {
                    for (CharSequence s : event.getText()) {
                        sb.append(s);
                    }
                    if(sb.toString().equals("Incoming video call"))
                        Log.d( "onAccessibilityEvent", "whatsapp video call" );

                }
            }
        }
    }

    @Override
    public void onInterrupt() {

    }
}

Answer 1

I don't think you can do what you want. Using the AccessibilityService you can know when the video call comes in:

@Override
public void onAccessibilityEvent( AccessibilityEvent event )
{
    if(event.getEventType() == AccessibilityEvent.TYPE_NOTIFICATION_STATE_CHANGED)
    {
        if(event.getPackageName().equals("com.whatsapp"))
        {
            StringBuilder sb = new StringBuilder();
            List<CharSequence> texts = event.getText();
            if (!texts.isEmpty()) 
            {
                for (CharSequence s : event.getText()) 
                {
                    sb.append(s);
                }
                if(sb.toString().equals("Incoming video call"))
                {
                    Log.d( "onAccessibilityEvent", "whatsapp video call" );
                }
            }
        }
    }
}

However, I've never been able to answer the call programmatically. The question at How can incoming calls be answered programmatically in Android 5.0 (Lollipop)? does a great job of enumerating all possible options, but most require root and/or being a system app.

Answer 2

You can use sendKeyDownUpSync method from Instrumentation class.

Instrumentation inst = new Instrumentation();
inst.sendKeyDownUpSync(KeyEvent.KEYCODE_HEADSETHOOK);

if this code didn't work, try to use another KeyEvent to find the correct one.

You can see the list of KeyEvent from this link : https://developer.android.com/reference/android/view/KeyEvent.html

You can check more info in from here : Instrumentation

Answer 3

A classic way to achieve this is to observe notifications using the NotificationListenerService and act on the relevant action of the notification.