How to print a text file using WiFi Direct

Question

I have a working Android app that displays user stats. I want to send a small report with plain text format (.txt) to a WiFi Direct printer. I have downloaded the sample demo app from Android. I did the proper modification in order to look for .txt file. But I don't understand why my code is not working. After selecting the file I want to print, nothing happens.

The current configuration for my EPSON printer bellow.

Wi-Fi Direct Mode : On
Communication Mode: AP
Operation Mode: IEEE802.11g/n
Communication Speed: Auto
SSID: DIRECT-D3A36C54
Channel: 7
Security Level: WPA2-PSK(AES)
Link Status: Unknown

This is the DeviceDetailFragment class

public class DeviceDetailFragment extends Fragment implements WifiP2pManager.ConnectionInfoListener {
    protected static final int CHOOSE_FILE_RESULT_CODE = 20;
    private View mContentView = null;
    private WifiP2pDevice device;
    private WifiP2pInfo info;
    ProgressDialog progressDialog = null;
    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        mContentView = inflater.inflate(R.layout.device_detail, null);
        mContentView.findViewById(R.id.btn_connect).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                WifiP2pConfig config = new WifiP2pConfig();
                config.deviceAddress = device.deviceAddress;
                config.wps.setup = WpsInfo.LABEL;
                config.wps.pin = "12345677";
//                config.groupOwnerIntent = 15;
                if (progressDialog != null && progressDialog.isShowing()) {
                    progressDialog.dismiss();
                }
                progressDialog = ProgressDialog.show(getActivity(), "Press back to cancel",
                        "Connecting to :" + device.deviceAddress, true, true
//                        new DialogInterface.OnCancelListener() {
//
//                            @Override
//                            public void onCancel(DialogInterface dialog) {
//                                ((DeviceActionListener) getActivity()).cancelDisconnect();
//                            }
//                        }
                );
                ((DeviceListFragment.DeviceActionListener) getActivity()).connect(config);
            }
        });
        mContentView.findViewById(R.id.btn_disconnect).setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        ((DeviceListFragment.DeviceActionListener) getActivity()).disconnect();
                    }
                });
        mContentView.findViewById(R.id.btn_start_client).setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        // Allow user to pick a text file from storage or other
                        // registered apps
                        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
                        intent.setType("text/*");
//                        intent.setType("image/*");
                        startActivityForResult(intent, CHOOSE_FILE_RESULT_CODE);
                    }
                });
        return mContentView;
    }
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        // User has picked a text file. Transfer it to group owner i.e peer using
        // FileTransferService.
        Uri uri = data.getData();
        TextView statusText = (TextView) mContentView.findViewById(R.id.status_text);
        statusText.setText("Sending: " + uri);
        Log.d(WiFiDirectActivity.TAG, "Intent----------- " + uri);
        Intent serviceIntent = new Intent(getActivity(), FileTransferService.class);
        serviceIntent.setAction(FileTransferService.ACTION_SEND_FILE);
        serviceIntent.putExtra(FileTransferService.EXTRAS_FILE_PATH, uri.toString());
        serviceIntent.putExtra(FileTransferService.EXTRAS_GROUP_OWNER_ADDRESS,
                info.groupOwnerAddress.getHostAddress());
        serviceIntent.putExtra(FileTransferService.EXTRAS_GROUP_OWNER_PORT, 8315); //631
        getActivity().startService(serviceIntent);
    }
    @Override
    public void onConnectionInfoAvailable(final WifiP2pInfo info) {
        if (progressDialog != null && progressDialog.isShowing()) {
            progressDialog.dismiss();
        }
        this.info = info;
        this.getView().setVisibility(View.VISIBLE);
        // The owner IP is now known.
        TextView view = (TextView) mContentView.findViewById(R.id.group_owner);
        view.setText(getResources().getString(R.string.group_owner_text)
                + ((info.isGroupOwner == true) ? getResources().getString(R.string.yes)
                : getResources().getString(R.string.no)));
        // InetAddress from WifiP2pInfo struct.
        view = (TextView) mContentView.findViewById(R.id.device_info);
        view.setText("Group Owner IP - " + info.groupOwnerAddress.getHostAddress());
        // After the group negotiation, we assign the group owner as the file
        // server. The file server is single threaded, single connection server
        // socket.
        if (info.groupFormed && info.isGroupOwner) {
            new FileServerAsyncTask(getActivity(), mContentView.findViewById(R.id.status_text))
                    .execute();
        } else if (info.groupFormed) {
            // The other device acts as the client. In this case, we enable the
            // get file button.
            mContentView.findViewById(R.id.btn_start_client).setVisibility(View.VISIBLE);
            ((TextView) mContentView.findViewById(R.id.status_text)).setText(getResources()
                    .getString(R.string.client_text));
        }
        // hide the connect button
        mContentView.findViewById(R.id.btn_connect).setVisibility(View.GONE);
    }
    /**
     * Updates the UI with device data
     *
     * @param device the device to be displayed
     */
    public void showDetails(WifiP2pDevice device) {
        this.device = device;
        this.getView().setVisibility(View.VISIBLE);
        TextView view = (TextView) mContentView.findViewById(R.id.device_address);
        view.setText(device.deviceAddress);
        view = (TextView) mContentView.findViewById(R.id.device_info);
        view.setText(device.toString());
    }
    /**
     * Clears the UI fields after a disconnect or direct mode disable operation.
     */
    public void resetViews() {
        mContentView.findViewById(R.id.btn_connect).setVisibility(View.VISIBLE);
        TextView view = (TextView) mContentView.findViewById(R.id.device_address);
        view.setText(R.string.empty);
        view = (TextView) mContentView.findViewById(R.id.device_info);
        view.setText(R.string.empty);
        view = (TextView) mContentView.findViewById(R.id.group_owner);
        view.setText(R.string.empty);
        view = (TextView) mContentView.findViewById(R.id.status_text);
        view.setText(R.string.empty);
        mContentView.findViewById(R.id.btn_start_client).setVisibility(View.GONE);
        this.getView().setVisibility(View.GONE);
    }
    /**
     * A simple server socket that accepts connection and writes some data on
     * the stream.
     */
    public static class FileServerAsyncTask extends AsyncTask<Void, Void, String> {
        private Context context;
        private TextView statusText;
        /**
         * @param context
         * @param statusText
         */
        public FileServerAsyncTask(Context context, View statusText) {
            this.context = context;
            this.statusText = (TextView) statusText;
        }
        @Override
        protected String doInBackground(Void... params) {
            try {
                ServerSocket serverSocket = new ServerSocket(8315); //631
                Log.d(WiFiDirectActivity.TAG, "Server: Socket opened");
                Socket client = serverSocket.accept();

                Log.d(WiFiDirectActivity.TAG, "Server: connection done");
//                final File f = new File(Environment.getExternalStorageDirectory() + "/"
//                        + context.getPackageName() + "/wifip2pshared-" + System.currentTimeMillis()
//                        + ".txt");


                final File f = new File(Environment.getExternalStorageDirectory() + "/"
                        + context.getPackageName() + "/wifip2pshared-" + ".txt");
                File dirs = new File(f.getParent());
                if (!dirs.exists())
                    dirs.mkdirs();
                f.createNewFile();
                Log.d(WiFiDirectActivity.TAG, "server: copying files " + f.toString());
                InputStream inputstream = client.getInputStream();
                copyFile(inputstream, new FileOutputStream(f));
                serverSocket.close();
                return f.getAbsolutePath();
            } catch (IOException e) {
                Log.e(WiFiDirectActivity.TAG, e.getMessage());
                return null;
            }
        }
        /*
         * (non-Javadoc)
         * @see android.os.AsyncTask#onPostExecute(java.lang.Object)
         */
        @Override
        protected void onPostExecute(String result) {
            if (result != null) {
                statusText.setText("File copied - " + result);
//                Log.e("...File copied - ", result);
                Intent intent = new Intent();
                intent.setAction(android.content.Intent.ACTION_VIEW);
                intent.setDataAndType(Uri.parse("file://" + result), "text/*");
                context.startActivity(intent);
            } else {
                Log.e("File copied is NULL- ", result);
            }
        }
        /*
         * (non-Javadoc)
         * @see android.os.AsyncTask#onPreExecute()
         */
        @Override
        protected void onPreExecute() {
            statusText.setText("Opening a server socket");
        }
    }
    public static boolean copyFile(InputStream inputStream, OutputStream out) {
        byte buf[] = new byte[1024];
        int len;
        try {
            while ((len = inputStream.read(buf)) != -1) {
                out.write(buf, 0, len);
            }
            out.close();
            inputStream.close();
        } catch (IOException e) {
            Log.d(WiFiDirectActivity.TAG, e.toString());
            return false;
        }
        return true;
    }
}

EDIT #1 This is my permission setting

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.BIND_PRINT_SERVICE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

After connecting to the printer, I've got the UI to select the file, after I select it, nothing happens, I just got the below console output (the file I am picking up is located in the SD card)

05-17 10:39:50.994 28659-28659/com.example.ccano.wifidirect E/ViewRootImpl: sendUserActionEvent() mView == null

05-17 10:39:52.314 28659-28659/com.example.ccano.wifidirect D/ViewRootImpl: ViewPostImeInputStage processPointer 0

05-17 10:39:52.384 28659-28659/com.example.ccano.wifidirect D/ViewRootImpl: ViewPostImeInputStage processPointer 1

05-17 10:39:56.484 28659-28659/com.example.ccano.wifidirect D/wifidirectdemo: Intent-----------
content://com.android.externalstorage.documents/document/9C33-6BBD%3Asample_file.txt

05-17 10:39:56.514 28659-28659/com.example.ccano.wifidirect D/wifidirectdemo: P2P state changed - 2

05-17 10:39:56.514 28659-29309/com.example.ccano.wifidirect D/wifidirectdemo: Opening client socket -

05-17 10:39:56.514 28659-28659/com.example.ccano.wifidirect D/wifidirectdemo: Peer status :0

05-17 10:39:56.524 28659-29309/com.example.ccano.wifidirect D/wifidirectdemo: Client socket - true

05-17 10:39:56.524 28659-29309/com.example.ccano.wifidirect E/ccano..copyfile: true

05-17 10:39:56.524 28659-29309/com.example.ccano.wifidirect D/wifidirectdemo: Client: Data written

05-17 10:39:56.534 28659-28659/com.example.ccano.wifidirect I/Timeline: Timeline: Activity_idle id:
android.os.BinderProxy@75dd5e time:4602644

05-17 10:41:01.714 28659-28659/com.example.ccano.wifidirect D/ViewRootImpl: ViewPostImeInputStage processPointer 0

05-17 10:41:01.774 28659-28659/com.example.ccano.wifidirect D/ViewRootImpl: ViewPostImeInputStage processPointer 1

05-17 10:41:02.564 28659-28659/com.example.ccano.wifidirect D/wifidirectdemo: P2P peers changed

05-17 10:41:02.574 28659-28659/com.example.ccano.wifidirect D/wifidirectdemo: Peer status :3

05-17 10:41:02.594 28659-28659/com.example.ccano.wifidirect D/wifidirectdemo: No devices found

EDIT #2

After adding the below line into my manifiest, still I am getting same result, nothing happens.

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

Edit #3

After changing WpsInfo.Label to WpsInfo.PBC now, I am getting a different output on the debugger console. (see screen shot below). But, still I the printer is not sending the print job.

Can you provide more details about "nothing happens", is the WiFi Direct connection established? At which point does it fail from the output log? — Nonos, May 10 '17 at 21:09
The project is using Android 6.0 API level 23. The log show that the file was sent and the proper handshake was established. — Carlos, May 11 '17 at 13:27
Those permissions where set at the very beginning, since I cloned the Android demo described above in my description.see my re-edit post. — Carlos, May 17 '17 at 19:54
are you sure your printer supports printing a txt file just by dumping it? I believe you may need to use ipp printing protocol to communicate with the printer. — Nonos, May 23 '17 at 20:08
set targetSdkVersion 22 (or you need to implement run time permissions) — phnmnn, May 23 '17 at 20:32

score 2 · Accepted Answer · answered May 26 '17 at 16:23

It turned out that my code was fine, after several days of testing and doing research, I found out that the issue was the socket class, I was using the default one that Google provides in the demo code (which is the one I was using) but, after reading the official documentation from Wi-Fi.org I could understand that port number matters and, in order to make it work with WiFi Direct only you have to target port #631 and the printer will ask you about the PIN password in case that it is enabled. Now, if you want to use P2P and by-passing the password, you have to use the port #9100.

So, I did it using both ports 9100 and 631 and now I am printing txt files.

Now, if you want to print PDF, you just need to add:

intent.setType("application/pdf");

and

intent.setDataAndType(Uri.parse("file://" + result), "application/pdf");

to the DeviceDetailFragment class (the one is posted above).

I hope this post will provide a good understanding and inside about Android printing with P2P communication.

How to print a text file using WiFi Direct

1 Answers1