Dear Lebanese programmers,

I am working on my graduation project

It's about Network Coding: A way to optimize broadcast . I mean to implement it on mobile phones, and for that I need to connect the phones without the need for a router. So I decided to use Wifi-Direct or Android WiFiP2P API

I hope this isn't against this site's policy but , I already posted the question on StackOverflow. But it never even had one comment . I even added a bounty to no avail.

Link to question

I will post the question here, but if you have an account on SO with privilege to upvote posts, please gimme some upvotes so it would attract some people to it, I really need this fixed !

I am trying to connect multiple devices to a group owner that I select manually

I want the peers to connect to the group owner manually once they find him

I have 3 phones (no emulators), on each there is a "Create group" button with this click handler

    public void createWifiGroup(View view) {

        mManager.createGroup(mChannel, new WifiP2pManager.ActionListener() {
            @Override
            public void onSuccess() {

                mManager.requestGroupInfo(mChannel,new MyGroupInfoListener(MainActivity.this));

            }

            @Override
            public void onFailure(int reason) {

            }
        });

    }

As you can see I do `requestGroupInfo` and pass it a listener that is printing the following line in logs:

groupFormed: true isGroupOwner: true groupOwnerAddress: /192.168.49.1

So I suppose it succeeded

I also have a `MyPeerListener` class that the `BroadCastReceiver` calls when a `WIFI_P2P_PEERS_CHANGED_ACTION` action intent is received.

`MyPeerListener` will iterate through the peers and connect if it finds a group owner


     @Override
        public void onPeersAvailable(WifiP2pDeviceList wifiP2pDeviceList) {
            this.wifiP2pDeviceList = wifiP2pDeviceList;
            //Toast toast = Toast.makeText(receiver.mActivity, "I found some peers", Toast.LENGTH_LONG);
            // toast.show();
            Iterator<WifiP2pDevice> deviceListIterator = wifiP2pDeviceList.getDeviceList().iterator();
            boolean foundGroup = false;
            while (deviceListIterator.hasNext()) {
                final WifiP2pDevice device = deviceListIterator.next();
                if (!foundGroup && device.isGroupOwner() && !MainActivity.connected) {
    
                    //MainActivity.mManager.removeGroup(MainActivity.mChannel, null);
    
                    foundGroup = true;
    
                    final WifiP2pConfig config = new WifiP2pConfig();
                    //config.wps.setup = WpsInfo.PBC;
                    config.groupOwnerIntent = 0;
                    config.deviceAddress = device.deviceAddress;
                    
                    MainActivity.mManager.connect(MainActivity.mChannel, config, new WifiP2pManager.ActionListener() {
    
                        @Override
                        public void onSuccess() {
                            //success logic
                            Toast toast = Toast.makeText(receiver.mActivity, "connect success", Toast.LENGTH_SHORT);
                            toast.show();
                            MainActivity.connected = true;
                            MainActivity.mManager.requestGroupInfo(MainActivity.mChannel, new MyGroupInfoListener(receiver.mActivity));
                            MainActivity.mManager.requestConnectionInfo(MainActivity.mChannel, new MyConnectionInfoListener(receiver));
                             
    
                        }
    
                        @Override
                        public void onFailure(int reason) {
                            //failure logic
                            //MainActivity.connected = false;
                            Toast toast = Toast.makeText(receiver.mActivity, "connect fail, reason: " + reason, Toast.LENGTH_LONG);
                            toast.show();
                        }
    
                    });
                }
                ListView list = (ListView) receiver.mActivity.findViewById(R.id.device_list_view);
                list.setAdapter(new DeviceListViewAdapter(this, receiver.mActivity));
            }
            
            }
    
    
        }

(I am aware of the use of static variables and overall bad design , but this is a fast prototype to learn)

Now I get a `connect success` `Toast` but the `requestConnectionInfo` right after the connection shows me this line

    groupFormed: false isGroupOwner: false groupOwnerAddress: null

A call to requestGroupInfo also shows:

    group is null

This happens very often about 80% of the times. Sometimes it shows the default group IP `192.168.49.1` . But I'll be lucky if both the "slave" phones have correct group info.

When I try to connect a socket to the owner while the group info is null it fails with `destination host unreachable`. But when the group info is correct I can connect and send data properly.

So why is this happening ? How is it even possible that the connection succeeds but the group is null ?