java - Android - 通过 Wi-fi 传递简单的字符串？

Question

我有 Wi-fi 直接演示。因为我们可以将任何图像文件传输到其他设备。当连接另一台设备并显示从图库发送图像时。在另一边，它显示发送的图像。但我想发送一个简单的字符串，而在另一端我想为该字符串干杯。我在这里发布了他们实现文件传输的代码。我对这段代码很困惑。我不知道在哪里更改以仅传递字符串。请帮我。谢谢。

DeviceDetailFragment.java

/**
 * A fragment that manages a particular peer and allows interaction with device
 * i.e. setting up network connection and transferring data.
 */
public class DeviceDetailFragment extends Fragment implements 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.PBC;
                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();
//                            }
//                        }
                        );
                ((DeviceActionListener) getActivity()).connect(config);

            }
        });

        mContentView.findViewById(R.id.btn_disconnect).setOnClickListener(
                new View.OnClickListener() {

                    @Override
                    public void onClick(View v) {
                        ((DeviceActionListener) getActivity()).disconnect();
                    }
                });

        mContentView.findViewById(R.id.btn_start_client).setOnClickListener(
                new View.OnClickListener() {

                    @Override
                    public void onClick(View v) {
                        // Allow user to pick an image from Gallery or other
                        // registered apps
                        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
                        intent.setType("image/*");
                        startActivityForResult(intent, CHOOSE_FILE_RESULT_CODE);
                    }
                });

        return mContentView;
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {

        // User has picked an image. 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, 8988);
        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(8988);
                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()
                        + ".jpg");

                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);
                Intent intent = new Intent();
                intent.setAction(android.content.Intent.ACTION_VIEW);
                intent.setDataAndType(Uri.parse("file://" + result), "image/*");
                context.startActivity(intent);
            }

        }

        /*
         * (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;
        long startTime=System.currentTimeMillis();

        try {
            while ((len = inputStream.read(buf)) != -1) {
                out.write(buf, 0, len);
            }
            out.close();
            inputStream.close();
            long endTime=System.currentTimeMillis()-startTime;
            Log.v("","Time taken to transfer all bytes is : "+endTime);

        } catch (IOException e) {
            Log.d(WiFiDirectActivity.TAG, e.toString());
            return false;
        }
        return true;
    }

}

FileTransferService.java

/**
 * A service that process each file transfer request i.e Intent by opening a
 * socket connection with the WiFi Direct Group Owner and writing the file
 */
public class FileTransferService extends IntentService {

    private static final int SOCKET_TIMEOUT = 5000;
    public static final String ACTION_SEND_FILE = "com.example.android.wifidirect.SEND_FILE";
    public static final String EXTRAS_FILE_PATH = "file_url";
    public static final String EXTRAS_GROUP_OWNER_ADDRESS = "go_host";
    public static final String EXTRAS_GROUP_OWNER_PORT = "go_port";

    public FileTransferService(String name) {
        super(name);
    }

    public FileTransferService() {
        super("FileTransferService");
    }

    /*
     * (non-Javadoc)
     * @see android.app.IntentService#onHandleIntent(android.content.Intent)
     */
    @Override
    protected void onHandleIntent(Intent intent) {

        Context context = getApplicationContext();
        if (intent.getAction().equals(ACTION_SEND_FILE)) {
            String fileUri = intent.getExtras().getString(EXTRAS_FILE_PATH);
            String host = intent.getExtras().getString(EXTRAS_GROUP_OWNER_ADDRESS);
            Socket socket = new Socket();
            int port = intent.getExtras().getInt(EXTRAS_GROUP_OWNER_PORT);

            try {
                Log.d(WiFiDirectActivity.TAG, "Opening client socket - ");
                socket.bind(null);
                socket.connect((new InetSocketAddress(host, port)), SOCKET_TIMEOUT);

                Log.d(WiFiDirectActivity.TAG, "Client socket - " + socket.isConnected());
                OutputStream stream = socket.getOutputStream();
                ContentResolver cr = context.getContentResolver();
                InputStream is = null;
                try {
                    is = cr.openInputStream(Uri.parse(fileUri));
                } catch (FileNotFoundException e) {
                    Log.d(WiFiDirectActivity.TAG, e.toString());
                }
                DeviceDetailFragment.copyFile(is, stream);
                Log.d(WiFiDirectActivity.TAG, "Client: Data written");
            } catch (IOException e) {
                Log.e(WiFiDirectActivity.TAG, e.getMessage());
            } finally {
                if (socket != null) {
                    if (socket.isConnected()) {
                        try {
                            socket.close();
                        } catch (IOException e) {
                            // Give up
                            e.printStackTrace();
                        }
                    }
                }
            }

        }
    }
}

Answer 1

你可以这样做:

DeviceDetailFragment.java

    @Override
    protected String doInBackground(Void... params) {
        ServerSocket serverSocket = null;
        Socket client = null;
        DataInputStream inputstream = null;
        try {
            serverSocket = new ServerSocket(8988);
            client = serverSocket.accept();
            inputstream = new DataInputStream(client.getInputStream());
            String str = inputstream.readUTF();
            serverSocket.close();
            return str;
        } catch (IOException e) {
            Log.e(WiFiDirectActivity.TAG, e.getMessage());
            return null;
        }finally{
            if(inputstream != null){
               try{
                  inputstream.close();
               } catch (IOException e) {
                  Log.e(WiFiDirectActivity.TAG, e.getMessage());
               }
            }
            if(client != null){
               try{
                  client.close();
               } catch (IOException e) {
                  Log.e(WiFiDirectActivity.TAG, e.getMessage());
               }
            }
             if(serverSocket != null){
               try{
                  serverSocket.close();
               } catch (IOException e) {
                  Log.e(WiFiDirectActivity.TAG, e.getMessage());
               }
            }
        }
    }
    @Override
    protected void onPostExecute(String result) {
        if (result != null) {
          Toast.makeText(..., result, ...).show();;
        }

    }

文件传输服务.java

@Override
protected void onHandleIntent(Intent intent) {

    Context context = getApplicationContext();
    if (intent.getAction().equals(ACTION_SEND_FILE)) {
        String host = intent.getExtras().getString(EXTRAS_GROUP_OWNER_ADDRESS);
        Socket socket = new Socket();
        int port = intent.getExtras().getInt(EXTRAS_GROUP_OWNER_PORT);
        DataOutputStream stream = null;
        try {
            socket.connect((new InetSocketAddress(host, port)), SOCKET_TIMEOUT);
            stream = new DataOutputStream(socket.getOutputStream());
           stream.writeUTF("a string");
        } catch (IOException e) {
            Log.e(WiFiDirectActivity.TAG, e.getMessage());
        } finally {
            if (stream != null) {
                 try {
                    stream.close();
                 } catch (IOException e) {
                    e.printStackTrace();
                 }    
            }
            if (socket != null) {
                if (socket.isConnected()) {
                    try {
                        socket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

    }
}