1.配置权限

<uses-permission
        android:required="true"
        android:name="android.permission.ACCESS_WIFI_STATE"/>
    <uses-permission
        android:required="true"
        android:name="android.permission.CHANGE_WIFI_STATE"/>
    <uses-permission
        android:required="true"
        android:name="android.permission.INTERNET"/>
    ...

2.加入本地服务

 manager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
        channel = manager.initialize(this, getMainLooper(), null);

  //  Create a string map containing information about your service.
//可加入以下键值信息广播给其他人
        Map record = new HashMap();
        record.put("listenport", String.valueOf(SERVER_PORT));
        record.put("buddyname", "John Doe" + (int) (Math.random() * 1000));
        record.put("available", "visible");

        // Service information.  Pass it an instance name, service type
        // _protocol._transportlayer , and the map containing
        // information other devices will want once they connect to this one.
        WifiP2pDnsSdServiceInfo serviceInfo =
                WifiP2pDnsSdServiceInfo.newInstance("_test", "_presence._tcp", record);

        // Add the local service, sending the service info, network channel,
        // and listener that will be used to indicate success or failure of
        // the request.
        manager.addLocalService(channel, serviceInfo, new ActionListener() {
            @Override
            public void onSuccess() {
                // Command successful! Code isn't necessarily needed here,
                // Unless you want to update the UI or add logging statements.
            }

            @Override
            public void onFailure(int arg0) {
                // Command failed.  Check for P2P_UNSUPPORTED, ERROR, or BUSY
            }
        });

3.注册监听服务

final HashMap<String, String> buddies = new HashMap<String, String>();
//可获取其他servece广播的信息
DnsSdTxtRecordListener txtListener = new DnsSdTxtRecordListener() {
        @Override
        /* Callback includes:
         * fullDomain: full domain name: e.g "printer._ipp._tcp.local."
         * record: TXT record dta as a map of key/value pairs.
         * device: The device running the advertised service.
         */

        public void onDnsSdTxtRecordAvailable(
                String fullDomain, Map record, WifiP2pDevice device) {
                Log.d(TAG, "DnsSdTxtRecord available -" + record.toString());
                buddies.put(device.deviceAddress, record.get("buddyname"));
            }
        };
//可发现其他设备的信息
DnsSdServiceResponseListener servListener = new DnsSdServiceResponseListener() {
        @Override
        public void onDnsSdServiceAvailable(String instanceName, String registrationType,
                WifiP2pDevice resourceType) {

                // Update the device name with the human-friendly version from
                // the DnsTxtRecord, assuming one arrived.
                resourceType.deviceName = buddies
                        .containsKey(resourceType.deviceAddress) ? buddies
                        .get(resourceType.deviceAddress) : resourceType.deviceName;

                // Add to the custom adapter defined specifically for showing
                // wifi devices.
                WiFiDirectServicesList fragment = (WiFiDirectServicesList) getFragmentManager()
                        .findFragmentById(R.id.frag_peerlist);
                WiFiDevicesAdapter adapter = ((WiFiDevicesAdapter) fragment
                        .getListAdapter());

                adapter.add(resourceType);
                adapter.notifyDataSetChanged();
                Log.d(TAG, "onBonjourServiceAvailable " + instanceName);
        }
    };

manager.setDnsSdResponseListeners(channel, servListener, txtListener);
 

4.查找服务

//必须先进行addServiceRequest才能进行查找
 serviceRequest = WifiP2pDnsSdServiceRequest.newInstance();
        manager.addServiceRequest(channel, serviceRequest,
                new ActionListener() {

                    @Override
                    public void onSuccess() {
                        appendStatus("Added service discovery request");
                    }

                    @Override
                    public void onFailure(int arg0) {
                        appendStatus("Failed adding service discovery request");
                    }
                });

manager.discoverServices(channel, new ActionListener() {

            @Override
            public void onSuccess() {
                appendStatus("Service discovery initiated");
            }

            @Override
            public void onFailure(int arg0) {
                appendStatus("Service discovery failed");

            }
        });

5.连接服务

在注册监听的时候当发现服务可用时会回调onDnsSdServiceAvailable方法中获取到WifiP2pDevice对象

 WifiP2pConfig config = new WifiP2pConfig();
        config.deviceAddress = device.deviceAddress;
        config.wps.setup = WpsInfo.PBC;
        if (serviceRequest != null)
            //连接时removeServiceRequest
            manager.removeServiceRequest(channel, serviceRequest,
                    new ActionListener() {

                        @Override
                        public void onSuccess() {
                        }

                        @Override
                        public void onFailure(int arg0) {
                        }
                    });

        manager.connect(channel, config, new ActionListener() {

            @Override
            public void onSuccess() {
                appendStatus("Connecting to service");
            }

            @Override
            public void onFailure(int errorCode) {
                appendStatus("Failed connecting to service");
            }
        });

6.后续操作参考我的另外一篇文章

android wifi 点对点传输