How to merge Call programmatically while other call is running (Conference call)

Question

My requirement is like this: Say I am calling a number on that time and I want to call another number programmatically. So far what I have done is: I am able to call to a particular number while some call is already going. For example, suppose I am calling on number 123 and after 1 minute (by using Alarm Manger I trigger an event to call on another number 456 and that is done!

Intent intent = new Intent(Intent.ACTION_CALL);
intent.setData(Uri.parse("tel:456"));
startActivity(intent);

I am using such intent to call and now I am able to see the screen on my phone with a button to merge the calls:

In this image you can see a button of Merging calls. Now when the user clicks on merge, it will merge all 3 Calls. I want to do it programmatically, not with the user interface.

Answer 1

Your question seemed interesting so I started digging in Android Source. Here is what I found:

The activity in the picture you posted is called InCallUI

When you start looking around you will find InCallPresenter which at line 463 has:

final boolean canMerge = activeCall.can(Capabilities.MERGE_CALLS);

and then at 472:

CallCommandClient.getInstance().merge();

when you check that merge() method in CallCommandClient you will find it uses ICallCommandService interface which I think is what you where looking for :)

Initialization of that CallCommandClient is in CallHandlerService around line 193.

Hope this helps & good luck.

PS. The APIs I listed are mostly internal Android stuff. You may have to use reflection to call it or it might not be possible at all - it may be inaccesible for your app because it's not marked as system app.

Answer 2

Android API doesn't support call merging facility you can see this thread for this. https://groups.google.com/forum/?fromgroups#!searchin/android-developers/conference$20call/android-developers/6OXDEe0tCks/8cuKdW1J9b8J but what you can do is open phone's call pad screen using aidl from there user can add another call or merge the call.

Answer 3

You cannot manage a conference with a smart phone. You need an intermediate service that can do this for you. You can program a conference manager using CCXML.

Voxeo has a good hosted platform for CCXML implementations and you can look at their documentation on how to setup conferencing. There are examples in "Learning CCXML 1.0\Multi-Party Conferencing in CCXML 1.0".

You can develop and test for free on Voxeo and they only start charging you if you put it into production. Another option is Twillio.

Here is a link to how you program a conference call on their platform.

Check the links you will get useful information. #courtesy- SO

Answer 4

Afaik, There is no API in the SDK which do merge call programmatically.

You have to work on the RIL (Radio Interface Layer) for Call Conference which android use for telephony calls.

Android's Radio Interface Layer (RIL) provides an abstraction layer between Android telephony services (android.telephony) and radio hardware. The RIL is radio agnostic, and includes support for Global System for Mobile communication (GSM)-based radios.

See here : http://www.kandroid.org/online-pdk/guide/telephony.html

Update

How does Modem code talk to Android code

http://fabiensanglard.net/cellphoneModem/index2.php

http://www.e-consystems.com/blog/android/?p=498

So you have to write the AT modem commands in the socket then rild invoke callback to the vendor library, then vendor library in turn delegates to the radio firmware.

Answer 5

After lots of search i got success in merging call, here i would like to share my finding with you. For reference i used this link

1. Use CallList.java in you project

package com.example.confrencecalldemo;

import android.os.Handler;
import android.os.Message;
import android.os.Trace;
import android.telecom.DisconnectCause;
import android.telecom.PhoneAccount;

import com.google.common.base.Preconditions;
import com.google.common.collect.Maps;

import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;


public class CallList {

    private static final int DISCONNECTED_CALL_SHORT_TIMEOUT_MS = 200;
    private static final int DISCONNECTED_CALL_MEDIUM_TIMEOUT_MS = 2000;
    private static final int DISCONNECTED_CALL_LONG_TIMEOUT_MS = 5000;

    private static final int EVENT_DISCONNECTED_TIMEOUT = 1;

    private static CallList sInstance = new CallList();

    private final HashMap<String, CallHelper> mCallById = new HashMap<>();
    private final HashMap<android.telecom.Call, CallHelper> mCallByTelecommCall = new HashMap<>();
    private final HashMap<String, List<String>> mCallTextReponsesMap = Maps.newHashMap();
    /**
     * ConcurrentHashMap constructor params: 8 is initial table size, 0.9f is
     * load factor before resizing, 1 means we only expect a single thread to
     * access the map so make only a single shard
     */
    private final Set<Listener> mListeners = Collections.newSetFromMap(
            new ConcurrentHashMap<Listener, Boolean>(8, 0.9f, 1));
    private final HashMap<String, List<CallUpdateListener>> mCallUpdateListenerMap = Maps
            .newHashMap();
    private final Set<CallHelper> mPendingDisconnectCalls = Collections.newSetFromMap(
            new ConcurrentHashMap<CallHelper, Boolean>(8, 0.9f, 1));

    /**
     * Static singleton accessor method.
     */
    public static CallList getInstance() {
        return sInstance;
    }

    /**
     * USED ONLY FOR TESTING
     * Testing-only constructor.  Instance should only be acquired through getInstance().
     */
    CallList() {
    }

    public void onCallAdded(android.telecom.Call telecommCall) {
        Trace.beginSection("onCallAdded");
        CallHelper call = new CallHelper(telecommCall);
//        Log.d(this, "onCallAdded: callState=" + call.getState());
        if (call.getState() == CallHelper.State.INCOMING ||
                call.getState() == CallHelper.State.CALL_WAITING) {
            onIncoming(call, call.getCannedSmsResponses());
        } else {
            onUpdate(call);
        }
        Trace.endSection();
    }

    public void onCallRemoved(android.telecom.Call telecommCall) {
        if (mCallByTelecommCall.containsKey(telecommCall)) {
            CallHelper call = mCallByTelecommCall.get(telecommCall);
            if (updateCallInMap(call)) {
//                Log.w(this, "Removing call not previously disconnected " + call.getId());
            }
            updateCallTextMap(call, null);
        }
    }

    /**
     * Called when a single call disconnects.
     */
    public void onDisconnect(CallHelper call) {
        if (updateCallInMap(call)) {
//            Log.i(this, "onDisconnect: " + call);
            // notify those listening for changes on this specific change
            notifyCallUpdateListeners(call);
            // notify those listening for all disconnects
            notifyListenersOfDisconnect(call);
        }
    }

    /**
     * Called when a single call has changed.
     */
    public void onIncoming(CallHelper call, List<String> textMessages) {
        if (updateCallInMap(call)) {
//            Log.i(this, "onIncoming - " + call);
        }
        updateCallTextMap(call, textMessages);

        for (Listener listener : mListeners) {
            listener.onIncomingCall(call);
        }
    }

    public void onUpgradeToVideo(CallHelper call){
//        Log.d(this, "onUpgradeToVideo call=" + call);
        for (Listener listener : mListeners) {
            listener.onUpgradeToVideo(call);
        }
    }
    /**
     * Called when a single call has changed.
     */
    public void onUpdate(CallHelper call) {
        Trace.beginSection("onUpdate");
        onUpdateCall(call);
        notifyGenericListeners();
        Trace.endSection();
    }

    /**
     * Called when a single call has changed session modification state.
     *
     * @param call The call.
     * @param sessionModificationState The new session modification state.
     */
    public void onSessionModificationStateChange(CallHelper call, int sessionModificationState) {
        final List<CallUpdateListener> listeners = mCallUpdateListenerMap.get(call.getId());
        if (listeners != null) {
            for (CallUpdateListener listener : listeners) {
                listener.onSessionModificationStateChange(sessionModificationState);
            }
        }
    }

    /**
     * Called when the last forwarded number changes for a call.  With IMS, the last forwarded
     * number changes due to a supplemental service notification, so it is not pressent at the
     * start of the call.
     *
     * @param call The call.
     */
    public void onLastForwardedNumberChange(CallHelper call) {
        final List<CallUpdateListener> listeners = mCallUpdateListenerMap.get(call.getId());
        if (listeners != null) {
            for (CallUpdateListener listener : listeners) {
                listener.onLastForwardedNumberChange();
            }
        }
    }

    /**
     * Called when the child number changes for a call.  The child number can be received after a
     * call is initially set up, so we need to be able to inform listeners of the change.
     *
     * @param call The call.
     */
    public void onChildNumberChange(CallHelper call) {
        final List<CallUpdateListener> listeners = mCallUpdateListenerMap.get(call.getId());
        if (listeners != null) {
            for (CallUpdateListener listener : listeners) {
                listener.onChildNumberChange();
            }
        }
    }

    public void notifyCallUpdateListeners(CallHelper call) {
        final List<CallUpdateListener> listeners = mCallUpdateListenerMap.get(call.getId());
        if (listeners != null) {
            for (CallUpdateListener listener : listeners) {
                listener.onCallChanged(call);
            }
        }
    }

    /**
     * Add a call update listener for a call id.
     *
     * @param callId The call id to get updates for.
     * @param listener The listener to add.
     */
    public void addCallUpdateListener(String callId, CallUpdateListener listener) {
        List<CallUpdateListener> listeners = mCallUpdateListenerMap.get(callId);
        if (listeners == null) {
            listeners = new CopyOnWriteArrayList<CallUpdateListener>();
            mCallUpdateListenerMap.put(callId, listeners);
        }
        listeners.add(listener);
    }

    /**
     * Remove a call update listener for a call id.
     *
     * @param callId The call id to remove the listener for.
     * @param listener The listener to remove.
     */
    public void removeCallUpdateListener(String callId, CallUpdateListener listener) {
        List<CallUpdateListener> listeners = mCallUpdateListenerMap.get(callId);
        if (listeners != null) {
            listeners.remove(listener);
        }
    }

    public void addListener(Listener listener) {
        Preconditions.checkNotNull(listener);

        mListeners.add(listener);

        // Let the listener know about the active calls immediately.
        listener.onCallListChange(this);
    }

    public void removeListener(Listener listener) {
        if (listener != null) {
            mListeners.remove(listener);
        }
    }

    /**
     * TODO: Change so that this function is not needed. Instead of assuming there is an active
     * call, the code should rely on the status of a specific CallHelper and allow the presenters to
     * update the CallHelper object when the active call changes.
     */
    public CallHelper getIncomingOrActive() {
        CallHelper retval = getIncomingCall();
        if (retval == null) {
            retval = getActiveCall();
        }
        return retval;
    }

    public CallHelper getOutgoingOrActive() {
        CallHelper retval = getOutgoingCall();
        if (retval == null) {
            retval = getActiveCall();
        }
        return retval;
    }

    /**
     * A call that is waiting for {@link PhoneAccount} selection
     */
    public CallHelper getWaitingForAccountCall() {
        return getFirstCallWithState(CallHelper.State.SELECT_PHONE_ACCOUNT);
    }

    public CallHelper getPendingOutgoingCall() {
        return getFirstCallWithState(CallHelper.State.CONNECTING);
    }

    public CallHelper getOutgoingCall() {
        CallHelper call = getFirstCallWithState(CallHelper.State.DIALING);
        if (call == null) {
            call = getFirstCallWithState(CallHelper.State.REDIALING);
        }
        return call;
    }

    public CallHelper getActiveCall() {
        return getFirstCallWithState(CallHelper.State.ACTIVE);
    }

    public CallHelper getBackgroundCall() {
        return getFirstCallWithState(CallHelper.State.ONHOLD);
    }

    public CallHelper getDisconnectedCall() {
        return getFirstCallWithState(CallHelper.State.DISCONNECTED);
    }

    public CallHelper getDisconnectingCall() {
        return getFirstCallWithState(CallHelper.State.DISCONNECTING);
    }

    public CallHelper getSecondBackgroundCall() {
        return getCallWithState(CallHelper.State.ONHOLD, 1);
    }

    public CallHelper getActiveOrBackgroundCall() {
        CallHelper call = getActiveCall();
        if (call == null) {
            call = getBackgroundCall();
        }
        return call;
    }

    public CallHelper getIncomingCall() {
        CallHelper call = getFirstCallWithState(CallHelper.State.INCOMING);
        if (call == null) {
            call = getFirstCallWithState(CallHelper.State.CALL_WAITING);
        }

        return call;
    }

    public CallHelper getFirstCall() {
        CallHelper result = getIncomingCall();
        if (result == null) {
            result = getPendingOutgoingCall();
        }
        if (result == null) {
            result = getOutgoingCall();
        }
        if (result == null) {
            result = getFirstCallWithState(CallHelper.State.ACTIVE);
        }
        if (result == null) {
            result = getDisconnectingCall();
        }
        if (result == null) {
            result = getDisconnectedCall();
        }
        return result;
    }

    public boolean hasLiveCall() {
        CallHelper call = getFirstCall();
        if (call == null) {
            return false;
        }
        return call != getDisconnectingCall() && call != getDisconnectedCall();
    }


    public CallHelper getVideoUpgradeRequestCall() {
        for(CallHelper call : mCallById.values()) {
            if (call.getSessionModificationState() ==
                    CallHelper.SessionModificationState.RECEIVED_UPGRADE_TO_VIDEO_REQUEST) {
                return call;
            }
        }
        return null;
    }

    public CallHelper getCallById(String callId) {
        return mCallById.get(callId);
    }

    public CallHelper getCallByTelecommCall(android.telecom.Call telecommCall) {
        return mCallByTelecommCall.get(telecommCall);
    }

    public List<String> getTextResponses(String callId) {
        return mCallTextReponsesMap.get(callId);
    }

    /**
     * Returns first call found in the call map with the specified state.
     */
    public CallHelper getFirstCallWithState(int state) {
        return getCallWithState(state, 0);
    }

    /**
     * Returns the [position]th call found in the call map with the specified state.
     * TODO: Improve this logic to sort by call time.
     */
    public CallHelper getCallWithState(int state, int positionToFind) {
        CallHelper retval = null;
        int position = 0;
        for (CallHelper call : mCallById.values()) {
            if (call.getState() == state) {
                if (position >= positionToFind) {
                    retval = call;
                    break;
                } else {
                    position++;
                }
            }
        }

        return retval;
    }

    /**
     * This is called when the service disconnects, either expectedly or unexpectedly.
     * For the expected case, it's because we have no calls left.  For the unexpected case,
     * it is likely a crash of phone and we need to clean up our calls manually.  Without phone,
     * there can be no active calls, so this is relatively safe thing to do.
     */
    public void clearOnDisconnect() {
        for (CallHelper call : mCallById.values()) {
            final int state = call.getState();
            if (state != CallHelper.State.IDLE &&
                    state != CallHelper.State.INVALID &&
                    state != CallHelper.State.DISCONNECTED) {

                call.setState(CallHelper.State.DISCONNECTED);
                call.setDisconnectCause(new DisconnectCause(DisconnectCause.UNKNOWN));
                updateCallInMap(call);
            }
        }
        notifyGenericListeners();
    }

    /**
     * Called when the user has dismissed an error dialog. This indicates acknowledgement of
     * the disconnect cause, and that any pending disconnects should immediately occur.
     */
    public void onErrorDialogDismissed() {
        final Iterator<CallHelper> iterator = mPendingDisconnectCalls.iterator();
        while (iterator.hasNext()) {
            CallHelper call = iterator.next();
            iterator.remove();
            finishDisconnectedCall(call);
        }
    }

    /**
     * Processes an update for a single call.
     *
     * @param call The call to update.
     */
    private void onUpdateCall(CallHelper call) {
//        Log.d(this, "\t" + call);
        if (updateCallInMap(call)) {
//            Log.i(this, "onUpdate - " + call);
        }
        updateCallTextMap(call, call.getCannedSmsResponses());
        notifyCallUpdateListeners(call);
    }

    /**
     * Sends a generic notification to all listeners that something has changed.
     * It is up to the listeners to call back to determine what changed.
     */
    private void notifyGenericListeners() {
        for (Listener listener : mListeners) {
            listener.onCallListChange(this);
        }
    }

    private void notifyListenersOfDisconnect(CallHelper call) {
        for (Listener listener : mListeners) {
            listener.onDisconnect(call);
        }
    }

    /**
     * Updates the call entry in the local map.
     * @return false if no call previously existed and no call was added, otherwise true.
     */
    private boolean updateCallInMap(CallHelper call) {
        Preconditions.checkNotNull(call);

        boolean updated = false;

        if (call.getState() == CallHelper.State.DISCONNECTED) {
            // update existing (but do not add!!) disconnected calls
            if (mCallById.containsKey(call.getId())) {
                // For disconnected calls, we want to keep them alive for a few seconds so that the
                // UI has a chance to display anything it needs when a call is disconnected.

                // Set up a timer to destroy the call after X seconds.
                final Message msg = mHandler.obtainMessage(EVENT_DISCONNECTED_TIMEOUT, call);
                mHandler.sendMessageDelayed(msg, getDelayForDisconnect(call));
                mPendingDisconnectCalls.add(call);

                mCallById.put(call.getId(), call);
                mCallByTelecommCall.put(call.getTelecommCall(), call);
                updated = true;
            }
        } else if (!isCallDead(call)) {
            mCallById.put(call.getId(), call);
            mCallByTelecommCall.put(call.getTelecommCall(), call);
            updated = true;
        } else if (mCallById.containsKey(call.getId())) {
            mCallById.remove(call.getId());
            mCallByTelecommCall.remove(call.getTelecommCall());
            updated = true;
        }

        return updated;
    }

    private int getDelayForDisconnect(CallHelper call) {
        Preconditions.checkState(call.getState() == CallHelper.State.DISCONNECTED);


        final int cause = call.getDisconnectCause().getCode();
        final int delay;
        switch (cause) {
            case DisconnectCause.LOCAL:
                delay = DISCONNECTED_CALL_SHORT_TIMEOUT_MS;
                break;
            case DisconnectCause.REMOTE:
            case DisconnectCause.ERROR:
                delay = DISCONNECTED_CALL_MEDIUM_TIMEOUT_MS;
                break;
            case DisconnectCause.REJECTED:
            case DisconnectCause.MISSED:
            case DisconnectCause.CANCELED:
                // no delay for missed/rejected incoming calls and canceled outgoing calls.
                delay = 0;
                break;
            default:
                delay = DISCONNECTED_CALL_LONG_TIMEOUT_MS;
                break;
        }

        return delay;
    }

    private void updateCallTextMap(CallHelper call, List<String> textResponses) {
        Preconditions.checkNotNull(call);

        if (!isCallDead(call)) {
            if (textResponses != null) {
                mCallTextReponsesMap.put(call.getId(), textResponses);
            }
        } else if (mCallById.containsKey(call.getId())) {
            mCallTextReponsesMap.remove(call.getId());
        }
    }

    private boolean isCallDead(CallHelper call) {
        final int state = call.getState();
        return CallHelper.State.IDLE == state || CallHelper.State.INVALID == state;
    }

    /**
     * Sets up a call for deletion and notifies listeners of change.
     */
    private void finishDisconnectedCall(CallHelper call) {
        if (mPendingDisconnectCalls.contains(call)) {
            mPendingDisconnectCalls.remove(call);
        }
        call.setState(CallHelper.State.IDLE);
        updateCallInMap(call);
        notifyGenericListeners();
    }

    /**
     * Notifies all video calls of a change in device orientation.
     *
     * @param rotation The new rotation angle (in degrees).
     */
    public void notifyCallsOfDeviceRotation(int rotation) {
        for (CallHelper call : mCallById.values()) {
            // First, ensure a VideoCall is set on the call so that the change can be sent to the
            // provider (a VideoCall can be present for a call that does not currently have video,
            // but can be upgraded to video).
            // Second, ensure that the call videoState has video enabled (there is no need to set
            // device orientation on a voice call which has not yet been upgraded to video).
            if (call.getVideoCall() != null && CallUtils.isVideoCall(call)) {
                call.getVideoCall().setDeviceOrientation(rotation);
            }
        }
    }

    /**
     * Handles the timeout for destroying disconnected calls.
     */
    private Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case EVENT_DISCONNECTED_TIMEOUT:
//                    Log.d(this, "EVENT_DISCONNECTED_TIMEOUT ", msg.obj);
                    finishDisconnectedCall((CallHelper) msg.obj);
                    break;
                default:
//                    Log.wtf(this, "Message not expected: " + msg.what);
                    break;
            }
        }
    };

    /**
     * Listener interface for any class that wants to be notified of changes
     * to the call list.
     */
    public interface Listener {
        /**
         * Called when a new incoming call comes in.
         * This is the only method that gets called for incoming calls. Listeners
         * that want to perform an action on incoming call should respond in this method
         * because {@link #onCallListChange} does not automatically get called for
         * incoming calls.
         */
        public void onIncomingCall(CallHelper call);
        /**
         * Called when a new modify call request comes in
         * This is the only method that gets called for modify requests.
         */
        public void onUpgradeToVideo(CallHelper call);
        /**
         * Called anytime there are changes to the call list.  The change can be switching call
         * states, updating information, etc. This method will NOT be called for new incoming
         * calls and for calls that switch to disconnected state. Listeners must add actions
         * to those method implementations if they want to deal with those actions.
         */
        public void onCallListChange(CallList callList);

        /**
         * Called when a call switches to the disconnected state.  This is the only method
         * that will get called upon disconnection.
         */
        public void onDisconnect(CallHelper call);


    }

    public interface CallUpdateListener {
        // TODO: refactor and limit arg to be call state.  Caller info is not needed.
        public void onCallChanged(CallHelper call);

        /**
         * Notifies of a change to the session modification state for a call.
         *
         * @param sessionModificationState The new session modification state.
         */
        public void onSessionModificationStateChange(int sessionModificationState);

        /**
         * Notifies of a change to the last forwarded number for a call.
         */
        public void onLastForwardedNumberChange();

        /**
         * Notifies of a change to the child number for a call.
         */
        public void onChildNumberChange();
    }
}

2.Call methods of CallList.java from InCallService class.

@Override
    public void onCallAdded(Call call) {
        super.onCallAdded(call);
        Log.d("MyConnectionService","onCallAdded");

        CallList.getInstance().onCallAdded(call);
        
    }

    @Override
    public void onCallRemoved(Call call) {
        super.onCallRemoved(call);
        Log.d("MyConnectionService","onCallRemoved"); 

        CallList.getInstance().onCallRemoved(call);
    }

3. finally call function to merge call

public void mergeCall() {

        final CallList calls = CallList.getInstance();
        CallHelper activeCall = calls.getActiveCall();

        if (activeCall != null) {

            final boolean canMerge = activeCall.can(
                    android.telecom.Call.Details.CAPABILITY_MERGE_CONFERENCE);
            final boolean canSwap = activeCall.can(
                    android.telecom.Call.Details.CAPABILITY_SWAP_CONFERENCE);
            // (2) Attempt actions on conference calls
            if (canMerge) {
                TelecomAdapter.getInstance().merge(activeCall.getId());

            } else if (canSwap) {
                TelecomAdapter.getInstance().swap(activeCall.getId());
            }
        }
    }

I am editing my answer, i forgot to place CallHelper.java class. Please visit below link for CallHelper.java file.

https://gist.github.com/amitsemwal1/4e9ca712adc8daaf070a0cc0e0d58c26

Answer 6

There is no api for getting conference call in android, you may want to play with the root system and get your work done.

officially android is not providing any api for conference call. You can study more for root access play here

http://www.kandroid.org/online-pdk/guide/telephony.html