如何使用WiFi Direct打印文本文件

Question

我有一个可以显示用户统计数据的Android应用程序。我想将一个小型纯文本格式(.txt)的报告发送到WiFi直接打印机。我从Android下载了示例演示应用程序。我进行了适当的修改以查找.txt文件。但是我不明白为什么我的代码不起作用。在选择要打印的文件后，什么也没有发生。 我的EPSON打印机的当前配置如下。 - Wi-Fi直接模式：开启 - 通信模式：AP - 操作模式：IEEE802.11g/n - 通信速度：自动 - SSID：DIRECT-D3A36C54 - 频道：7 - 安全级别：WPA2-PSK(AES) - 连接状态：未知 这是DeviceDetailFragment类

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;
    }
}

编辑 #1 这是我的权限设置

<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" />

连接打印机后，我得到了选择文件的用户界面，但是在我选择文件后，什么也没有发生，我只看到下面的控制台输出（我选择的文件位于SD卡中）

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

编辑 #2

在我的清单中添加以下行后，仍然出现相同的结果，什么也没有发生。

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

编辑 #3

将WpsInfo.Label更改为WpsInfo.PBC后，现在我在调试控制台上得到了不同的输出（请参见下面的屏幕截图）。但是，打印机仍然没有发送打印作业。

- Carlos

---

安卓操作系统的版本？ - Onik

你能提供更多关于“什么都没发生”的细节吗？WiFi Direct连接是否已建立？从输出日志的哪个点开始失败？ - Nonos

该项目正在使用Android 6.0 API级别23。日志显示文件已发送并建立了正确的握手。 - Carlos

你是否已添加存储所需的权限： '''<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> ''' - firegnom

这些权限是在最开始设置的，因为我克隆了上述描述中的Android演示。请查看我的重新编辑的帖子。 - Carlos

Answer 1

原来我的代码没问题，在经过几天的测试和研究后，我发现问题出在socket类上。我一直使用的是Google提供的演示代码中默认的socket类，但是在阅读Wi-Fi.org的官方文档后，我明白了端口号的重要性。为了使其仅与WiFi Direct配合工作，必须针对端口#631，如果已启用，则打印机会询问您PIN密码。现在，如果您想使用P2P并绕过密码，您需要使用端口#9100。

因此，我使用了9100和631两个端口，现在我可以打印txt文件了。

现在，如果您想打印PDF文件，只需添加：

intent.setType("application/pdf"); 

并且

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

希望你能够到DeviceDetailFragment类（如上所述）。

我希望这篇文章能够提供关于Android打印与P2P通信的良好理解和内部信息。

- Carlos