我的项目中有一个蓝牙服务，我连接了所有片段，但是无法使用Connected Thread发送消息。它无法正常工作。我的错在哪里？我正在寻找解决方案，因为3天找不到任何解决方案。 为什么我不能发送任何消息。我的日志返回：
BluetoothConnectionService.write(byte[])' on a null object reference
我知道ConnectedThread为空，但为什么为空？
public ConnectedThread(BluetoothSocket socket) {
Log.d(TAG, "ConnectedThread: Starting.");
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// ObjectInputStream tmpObjIn = null;
//ObjectOutputStream tmpObjOut = null;
if(socket!=null)
{
Log.d(TAG, "ConnectedThread: Socket not empty");
}
//dismiss the progressdialog when connection is established
try{
mProgressDialog.dismiss();
}catch (NullPointerException e){
e.printStackTrace();
}
try {
tmpIn = mmSocket.getInputStream();
tmpOut = mmSocket.getOutputStream();
//tmpObjOut = new ObjectOutputStream(tmpOut);
//tmpObjOut.flush();
//tmpObjIn = new ObjectInputStream(tmpIn);
} catch (IOException e) {
Log.d(TAG, "ConnectedThread: doest work OUTPUT");
e.printStackTrace();
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
// mObjectOutStream = tmpObjOut;
// mObjectInStream = tmpObjIn;
}
这就是所有service.java代码：
package com.example.duygu.mybluetoothdevicelist;
import android.app.ProgressDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.content.Intent;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.nio.charset.Charset;
import java.util.UUID;
public class BluetoothConnectionService {
private static final String TAG = "BluetoothConnectionServ";
private static final String appName = "MYAPP";
private static final UUID MY_UUID_INSECURE =
UUID.fromString("8ce255c0-200a-11e0-ac64-0800200c9a66");
private final BluetoothAdapter mBluetoothAdapter;
Context mContext;
private AcceptThread mInsecureAcceptThread;
private ConnectThread mConnectThread;
private BluetoothDevice mmDevice;
private UUID deviceUUID;
ProgressDialog mProgressDialog;
private BluetoothSocket mmSocket;
private ConnectedThread mConnectedThread;
public BluetoothConnectionService(Context context) {
mContext = context;
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
start();
}
/**
* This thread runs while listening for incoming connections. It behaves
* like a server-side client. It runs until a connection is accepted
* (or until cancelled).
*/
private class AcceptThread extends Thread {
// The local server socket
private final BluetoothServerSocket mmServerSocket;
public AcceptThread(){
BluetoothServerSocket tmp = null;
// Create a new listening server socket
try{
tmp = mBluetoothAdapter.listenUsingInsecureRfcommWithServiceRecord(appName, MY_UUID_INSECURE);
Log.d(TAG, "AcceptThread: Setting up Server using: " + MY_UUID_INSECURE);
}catch (IOException e){
Log.e(TAG, "AcceptThread: IOException: " + e.getMessage() );
}
mmServerSocket = tmp;
}
public void run(){
Log.d(TAG, "run: AcceptThread Running.");
BluetoothSocket socket = null;
try{
// This is a blocking call and will only return on a
// successful connection or an exception
Log.d(TAG, "run: RFCOM server socket start.....");
socket = mmServerSocket.accept();
Log.d(TAG, "run: RFCOM server socket accepted connection.");
}catch (IOException e){
Log.e(TAG, "AcceptThread: IOException: " + e.getMessage() );
}
//talk about this is in the 3rd
if(socket != null){
connected(socket,mmDevice);
}
Log.i(TAG, "END mAcceptThread ");
}
public void cancel() {
Log.d(TAG, "cancel: Canceling AcceptThread.");
try {
mmServerSocket.close();
} catch (IOException e) {
Log.e(TAG, "cancel: Close of AcceptThread ServerSocket failed. " + e.getMessage() );
}
}
}
/**
* This thread runs while attempting to make an outgoing connection
* with a device. It runs straight through; the connection either
* succeeds or fails.
*/
private class ConnectThread extends Thread {
public ConnectThread(BluetoothDevice device, UUID uuid) {
Log.d(TAG, "ConnectThread: started.");
mmDevice = device;
deviceUUID = uuid;
}
public void run(){
BluetoothSocket tmp = null;
Log.i(TAG, "RUN mConnectThread ");
// Get a BluetoothSocket for a connection with the
// given BluetoothDevice
try {
Log.d(TAG, "ConnectThread: Trying to create InsecureRfcommSocket using UUID: "
+MY_UUID_INSECURE );
tmp = mmDevice.createRfcommSocketToServiceRecord(deviceUUID);
} catch (IOException e) {
Log.e(TAG, "ConnectThread: Could not create InsecureRfcommSocket " + e.getMessage());
}
mmSocket = tmp;
// Always cancel discovery because it will slow down a connection
mBluetoothAdapter.cancelDiscovery();
// Make a connection to the BluetoothSocket
try {
// This is a blocking call and will only return on a
// successful connection or an exception
mmSocket.connect();
Log.d(TAG, "run: ConnectThread connected.");
} catch (IOException e) {
// Close the socket
try {
mmSocket.close();
Log.d(TAG, "run: Closed Socket.");
} catch (IOException e1) {
Log.e(TAG, "mConnectThread: run: Unable to close connection in socket " + e1.getMessage());
}
Log.d(TAG, "run: ConnectThread: Could not connect to UUID: " + MY_UUID_INSECURE );
}
//will talk about this in the 3rd video
connected(mmSocket,mmDevice);
}
public void cancel() {
try {
Log.d(TAG, "cancel: Closing Client Socket.");
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "cancel: close() of mmSocket in Connectthread failed. " + e.getMessage());
}
}
}
/**
* Start the chat service. Specifically start AcceptThread to begin a
* session in listening (server) mode. Called by the Activity onResume()
*/
public synchronized void start() {
Log.d(TAG, "start");
// Cancel any thread attempting to make a connection
if (mConnectThread != null) {
mConnectThread.cancel();
mConnectThread = null;
}
if (mInsecureAcceptThread == null) {
mInsecureAcceptThread = new AcceptThread();
mInsecureAcceptThread.start();
}
}
/**
AcceptThread starts and sits waiting for a connection.
Then ConnectThread starts and attempts to make a connection with the other devices AcceptThread.
**/
public void startClient(BluetoothDevice device,UUID uuid){
Log.d(TAG, "startClient: Started.");
//initprogress dialog
mProgressDialog = ProgressDialog.show(mContext,"Connecting Bluetooth"
,"Please Wait...",true);
mConnectThread = new ConnectThread(device, uuid);
mConnectThread.start();
}
/**
Finally the ConnectedThread which is responsible for maintaining the BTConnection, Sending the data, and
receiving incoming data through input/output streams respectively.
**/
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
//private final ObjectInputStream mObjectInStream;
// private final ObjectOutputStream mObjectOutStream;
public ConnectedThread(BluetoothSocket socket) {
Log.d(TAG, "ConnectedThread: Starting.");
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// ObjectInputStream tmpObjIn = null;
//ObjectOutputStream tmpObjOut = null;
if(socket!=null)
{
Log.d(TAG, "ConnectedThread: Socket not empty");
}
//dismiss the progressdialog when connection is established
try{
mProgressDialog.dismiss();
}catch (NullPointerException e){
e.printStackTrace();
}
try {
tmpIn = mmSocket.getInputStream();
tmpOut = mmSocket.getOutputStream();
//tmpObjOut = new ObjectOutputStream(tmpOut);
//tmpObjOut.flush();
//tmpObjIn = new ObjectInputStream(tmpIn);
} catch (IOException e) {
Log.d(TAG, "ConnectedThread: doest work OUTPUT");
e.printStackTrace();
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
// mObjectOutStream = tmpObjOut;
// mObjectInStream = tmpObjIn;
}
public void run(){
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
// Read from the InputStream
try {
bytes = mmInStream.read(buffer);
String incomingMessage = new String(buffer, 0, bytes);
Log.d(TAG, "InputStream: " + incomingMessage);
Intent incomingMessageIntent = new Intent("incomingMessage");
incomingMessageIntent.putExtra("theMessage", incomingMessage);
LocalBroadcastManager.getInstance(mContext).sendBroadcast(incomingMessageIntent);
} catch (IOException e) {
Log.e(TAG, "write: Error reading Input Stream. " + e.getMessage() );
break;
}
}
}
//Call this from the main activity to send data to the remote device
public void write(byte[] bytes) {
String text = new String(bytes, Charset.defaultCharset());
Log.d(TAG, "write: Writing to outputstream: " + text);
try {
mmOutStream.write(bytes);
} catch (IOException e) {
Log.e(TAG, "write: Error writing to output stream. " + e.getMessage() );
}
}
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
private void connected(BluetoothSocket mmSocket, BluetoothDevice mmDevice) {
Log.d(TAG, "connected: Starting.");
// Start the thread to manage the connection and perform transmissions
mConnectedThread = new ConnectedThread(mmSocket);
mConnectedThread.start();
}
/**
* Write to the ConnectedThread in an unsynchronized manner
*
* @param out The bytes to write
* @see ConnectedThread#write(byte[])
*/
public void write(byte[] out) { //changed this
// Create temporary object
ConnectedThread r;
r=mConnectedThread;
// Synchronize a copy of the ConnectedThread
Log.d(TAG, "write: Write Called.");
//perform the write
r.write(out);
}
}
答案 0 :(得分：0)
我找到了解决方案。如果使用片段，则只能接收消息，但不能发送消息。如果要发送消息，则必须使用MainActivity.java。如果要在片段上获取价值，请使用以下类型：
* MainActivty.java上的创建方法（即使用参数mBluetoothService.write（bytes）发送消息）
*在片段端，您必须编写要发送的方法。而且您必须将方法发送到MainActivity.java
我工作了5天，终于找到了解决方法。