CODEWITHSUNDEEP
androidwifi-directwifip2p
Kavin Zhao
Kavin Zhao

Reputation: 55

android - Connecting to a WiFi P2P device without discovering peers

I want to establish a WiFi-Direct Connection with another device peered through NFC. My steps are as follows:

First, Device A gets its own WiFiP2P address and transmits it to Device B via NFC.

Then, Device B tries to establish a connection with Device A using the provided address.

As you can see I didn't involve discovering peers in the process. But when Device B is trying to connect, the result is always failed (reason 0, this should be ERROR).

I think this might be related to device visibility, but I don't know and can't find any code to make a device visible.

Here's my code:

 //NOTE: These code should be executed on Device B
 //Starting WiFi Direct Transmission
 //First we should establish a connection
 WifiP2pConfig config = new WifiP2pConfig();
 config.deviceAddress = remoteWifiP2pDevice; 
 //remoteWifiP2pDevice is the address of device A obtained from NFC
 config.wps.setup = WpsInfo.PBC;
 mManager.connect(mChannel, config, new WifiP2pManager.ActionListener() {
        @Override
        public void onSuccess() {
            //success logic
            Toast.makeText(MainActivity.this, "success", Toast.LENGTH_SHORT).show();
            if (!FILE_RECV)
            {
                new SendFilesTask().execute("");
            }
        }
        @Override
        public void onFailure(int reason) {
            //failure logic
            Toast.makeText(MainActivity.this, "failed" + reason, Toast.LENGTH_SHORT).show();
        }
    });

In OnCreate() I have

intentFilter.addAction(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);         
mManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
mChannel = mManager.initialize(this, getMainLooper(), null);
mReceiver = new WiFiDirectBroadcastReceiver(mManager, mChannel, this);

The WifiDirectBroadcastReceiver has code only related to getting Device A's address and can be considered empty.

So what's wrong with these and how can I fix it? Thanks in advance.

P.S. If I connect Device A and B manually, and run my code again, it returns success.

Upvotes: 0

Views: 1412

Answers (2)

KP_
KP_

Reputation: 1866

  • WIfi Direct assumptions:

All the devices should be in discoverable (scanning mode) simultaneously.

Devices scan for a 30 sec and after that it stops by default.So we need to initiate scan programatically using discoverpeers method.

Most important is displaying nearby devices is device specific.ie sometimes devices wont show nearby ones eventhough they are available.Thats why wifi direct is not reliable and because of these, there wont be much wifi direct apps in play store.

Upvotes: 1

Kavin Zhao
Kavin Zhao

Reputation: 55

I have discovered that delaying several seconds will make the connection succeed. I don't know the reason, but this can be used as a workaround.

So after all is there a better solution to this? And why does the delay work?

Upvotes: 0

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