我已经阅读了大量的SO线程，我仍然感到困惑。我需要发送一个舰船对象，用于战舰游戏。我已经使船类实现了serializable，但我似乎无法发送该对象。我基本上只使用了我在网上找到的代码并将其纳入我的connectedThread代码（与android dev网站相同）。代码如下。谁能告诉我哪里出错了，非常感谢任何帮助。当我运行代码时出现错误，这似乎来自于objectinputstream端
public class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
private ObjectOutput out = null;
byte[] yourBytes = new byte[1024];
public ConnectedThread(BluetoothSocket socket) {
Log.d(TAG, "connectedthread started");
// mHandler.obtainMessage(TEST).sendToTarget();
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
yourBytes = null;
// Get the input and output streams, using temp objects because
// member streams are final
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
out = new ObjectOutputStream(bos);
} catch (IOException e) {
Log.e(TAG, "temp sockets not created");
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
Log.i(TAG, "Begin mConnectedThread");
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) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI activity
Log.i(TAG, "reaaaad msg");
mHandler.obtainMessage(SetUpGame.MESSAGE_READ2, bytes,
-1, buffer).sendToTarget();
Log.i(TAG, "READ OBJECT");
// ........................................THIS IS CODE THAT HAS ERRORS-----------
ByteArrayInputStream bis = new ByteArrayInputStream(yourBytes);
ObjectInput in = null;
try {
in = new ObjectInputStream(mmInStream);
Ship yourObject = (Ship) in.readObject();
//Log.i("Object received maybe", yourObject.toString());
if(yourObject!=null)
mHandler.obtainMessage(SetUpGame.MESSAGE_READ_OBJ, -1, -1, yourObject).sendToTarget();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
bis.close();
in.close();
}
// -----------------------------------IF I DELETE THE ABOVE CODE IT WORKS FOR STRINGS PERFECTLY------
}
catch (IOException e) {
Log.e(TAG, "disconnectd");
break;
}
}
}
/*
* Call this from the main activity to send data to the remote device
*/
public void write(byte[] buffer) {
try {
mmOutStream.write(buffer);
Log.i(TAG, "writeeee msg");
mHandler.obtainMessage(SetUpGame.MESSAGE_WRITE, -1, -1, buffer)
.sendToTarget();
} catch (IOException e) {
Log.e(TAG, "Exception during write");
}
}
public void writeObj(Ship ship) {
bos = new ByteArrayOutputStream();
ObjectOutput out = null;
try {
out = new ObjectOutputStream(mmOutStream);
out.writeObject(ship);
yourBytes = bos.toByteArray();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
out.close();
bos.close();
} catch (IOException e) {
Log.e(TAG, "close of connect socket failed");
}
}
}
和logcat：
03-21 02:41:41.594: E/AndroidRuntime(12529): java.lang.NullPointerException
03-21 02:41:41.594: E/AndroidRuntime(12529): at java.io.ByteArrayInputStream.<init>(ByteArrayInputStream.java:58)
03-21 02:41:41.594: E/AndroidRuntime(12529): at com.example.battleships.v2.ChatService$ConnectedThread.run(ChatService.java:280)
03-21 02:41:41.875: E/ActivityThread(12529): Activity com.example.battleships.v2.MainScreen has leaked IntentReceiver com.example.battleships.v2.MainScreen$2@40521320 that was originally registered here. Are you missing a call to unregisterReceiver()?
03-21 02:41:41.875: E/ActivityThread(12529): android.app.IntentReceiverLeaked: Activity com.example.battleships.v2.MainScreen has leaked IntentReceiver com.example.battleships.v2.MainScreen$2@40521320 that was originally registered here. Are you missing a call to unregisterReceiver()?
03-21 02:41:41.875: E/ActivityThread(12529): at android.app.LoadedApk$ReceiverDispatcher.<init>(LoadedApk.java:799)
03-21 02:41:41.875: E/ActivityThread(12529): at android.app.LoadedApk.getReceiverDispatcher(LoadedApk.java:575)
03-21 02:41:41.875: E/ActivityThread(12529): at android.app.ContextImpl.registerReceiverInternal(ContextImpl.java:865)
03-21 02:41:41.875: E/ActivityThread(12529): at android.app.ContextImpl.registerReceiver(ContextImpl.java:852)
03-21 02:41:41.875: E/ActivityThread(12529): at android.app.ContextImpl.registerReceiver(ContextImpl.java:846)
03-21 02:41:41.875: E/ActivityThread(12529): at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:318)
03-21 02:41:41.875: E/ActivityThread(12529): at com.example.battleships.v2.MainScreen.setUpUI(MainScreen.java:167)
03-21 02:41:41.875: E/ActivityThread(12529): at com.example.battleships.v2.MainScreen.onCreate(MainScreen.java:160)
03-21 02:41:41.875: E/ActivityThread(12529): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
03-21 02:41:41.875: E/ActivityThread(12529): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836)
03-21 02:41:41.875: E/ActivityThread(12529): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1893)
答案 0 :(得分：0)
看起来你已经通过在方法writeObj（）中重新声明它来重写类变量“out”。删除“ObjectOutput out = null;”来自writeObj（）。
当你继续重置类变量“bos”时，你似乎有点不确定要写入哪个流。
你可能会得到一个NullPointerException，因为你试图以你认为的方式使用不在范围内的变量。