I'm working on an Android project where i want to serialize a class object. I have looked around how to do this and i found out there are several solutions. The tried the following solution:
public static byte[] toByteArray(Object obj) throws IOException {
byte[] bytes = null;
ByteArrayOutputStream bos = null;
ObjectOutputStream oos = null;
try {
bos = new ByteArrayOutputStream();
oos = new ObjectOutputStream(bos);
oos.writeObject(obj);
oos.flush();
bytes = bos.toByteArray();
} finally {
if (oos != null) {
Log.i(TAG, "not null");
oos.close();
}
if (bos != null) {
bos.close();
Log.i(TAG, "not null");
}
}
return bytes;
}
The object that i'm trying to serialize is as followed defined:
// ObjectInfo struct definition
public class ObjectInfo implements java.io.Serializable
{
public int ObjectXCor;
public int ObjectYCor;
public int ObjectMass;
//Constructor
public ObjectInfo(){
ObjectMass = 0;
ObjectXCor = 0;
ObjectYCor = 0;
}
};
// ObjectInfo struct definition
public class SensorDataStruct implements java.io.Serializable
{
public int PingData;
public int IRData;
public int ForceData;
public int CompassData;
//Constructor
public SensorDataStruct(){
CompassData = 0;
ForceData = 0;
IRData = 0;
PingData = 0;
}
};
// ObjectInfo struct definition
public class CommStruct implements java.io.Serializable
{
public ObjectInfo VisionData;
public SensorDataStruct SensorData;
//Constructor
public CommStruct(){
// Call constructors
VisionData = new ObjectInfo();
SensorData = new SensorDataStruct();
}
};
The toByteArray method is called in a onClick method as followed:
try {
Log.i(TAG, "==== trying to serialize ====");
communicationmoduleUDSB.toByteArray(CMUSB.SendPacket);
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.i(TAG, "Failed to serialize!");
}
When i press the button that is attachted to te onClick method then i see that a exception is throwed. But i don't know why, does anyone have a idea? All suggestions are welcome!
The trace that is printed in the Catlog when the exception occurs (also added the first prints of the methods (not null):
10-30 12:21:15.474: I/CommunicatorApp:(12338): ==== trying to serialize ====
10-30 12:21:15.554: I/(12338): not null
10-30 12:21:15.554: I/(12338): not null
10-30 12:21:15.554: W/System.err(12338): java.io.NotSerializableException: com.example.communicationmodulebase.Server
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1364)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1671)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1517)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1481)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:979)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:368)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1074)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1404)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1671)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1517)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1481)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:979)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:368)
10-30 12:21:15.564: W/System.err(12338): at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1074)
10-30 12:21:15.574: W/System.err(12338): at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1404)
10-30 12:21:15.574: W/System.err(12338): at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1671)
10-30 12:21:15.574: W/System.err(12338): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1517)
10-30 12:21:15.594: W/System.err(12338): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1481)
10-30 12:21:15.604: W/System.err(12338): at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:979)
10-30 12:21:15.604: W/System.err(12338): at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:368)
10-30 12:21:15.604: W/System.err(12338): at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1074)
10-30 12:21:15.604: W/System.err(12338): at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1404)
10-30 12:21:15.614: W/System.err(12338): at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1671)
10-30 12:21:15.614: W/System.err(12338): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1517)
10-30 12:21:15.614: W/System.err(12338): at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1481)
10-30 12:21:15.614: W/System.err(12338): at com.example.communicationmoduleUSB.communicationmoduleUDSB.toByteArray(communicationmoduleUDSB.java:121)
10-30 12:21:15.614: W/System.err(12338): at com.example.communicationmodule.MainActivity$1.onClick(MainActivity.java:41)
10-30 12:21:15.614: W/System.err(12338): at android.view.View.performClick(View.java:4162)
10-30 12:21:15.624: W/System.err(12338): at android.view.View$PerformClick.run(View.java:17082)
10-30 12:21:15.624: W/System.err(12338): at android.os.Handler.handleCallback(Handler.java:615)
10-30 12:21:15.624: W/System.err(12338): at android.os.Handler.dispatchMessage(Handler.java:92)
10-30 12:21:15.624: W/System.err(12338): at android.os.Looper.loop(Looper.java:137)
10-30 12:21:15.634: W/System.err(12338): at android.app.ActivityThread.main(ActivityThread.java:4867)
10-30 12:21:15.634: W/System.err(12338): at java.lang.reflect.Method.invokeNative(Native Method)
10-30 12:21:15.634: W/System.err(12338): at java.lang.reflect.Method.invoke(Method.java:511)
10-30 12:21:15.634: W/System.err(12338): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
10-30 12:21:15.644: W/System.err(12338): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
10-30 12:21:15.644: W/System.err(12338): at dalvik.system.NativeStart.main(Native Method)
10-30 12:21:15.644: I/CommunicatorApp:(12338): Failed to serialize!
Update
For more information here are the CommunicationModule and CommunicationModuleUSB classes.
CommunicatoionModule (Base class):
package com.example.communicationmodulebaseclass;
public class communicationmodule implements java.io.Serializable
{
// ObjectInfo struct definition
public class ObjectInfo implements java.io.Serializable
{
public int ObjectXCor;
public int ObjectYCor;
public int ObjectMass;
//Constructor
public ObjectInfo(){
ObjectMass = 0;
ObjectXCor = 0;
ObjectYCor = 0;
}
};
// ObjectInfo struct definition
public class SensorDataStruct implements java.io.Serializable
{
public int PingData;
public int IRData;
public int ForceData;
public int CompassData;
//Constructor
public SensorDataStruct(){
CompassData = 0;
ForceData = 0;
IRData = 0;
PingData = 0;
}
};
// ObjectInfo struct definition
public class CommStruct implements java.io.Serializable
{
public ObjectInfo VisionData;
public SensorDataStruct SensorData;
//Constructor
public CommStruct(){
// Call constructors
VisionData = new ObjectInfo();
SensorData = new SensorDataStruct();
}
};
public CommStruct SendPacket;
public CommStruct RecievePacket;
public ObjectInfo Test;
public communicationmodule(){
}
public void SendBuffer(){
}
public void Send(){
}
public void RecieveBuffer(){
}
public void Recieve(){
}
}
And the CommuncationModuleUSB class that extens the CommuncationModule class
package com.example.communicationmoduleUSB;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import android.os.*;
import android.util.Log;
import com.example.communicationmodulebase.Server;
import com.example.communicationmodulebaseclass.communicationmodule;
import com.example.communicationmodulebaseclass.communicationmodule.CommStruct;
import com.example.communicationmodulebaseclass.communicationmodule.ObjectInfo;
public class communicationmoduleUDSB extends communicationmodule {
private static final String TAG = null;
public byte ArrayRecieved[] = new byte[2];
public byte ArrayOutput[] = new byte[2];
public boolean UseStructFunction = true;
// Create TCP server (based on MicroBridge LightWeight Server).
// Note: This Server runs in a separate thread.
Server server = null;
public communicationmoduleUDSB(){
SendPacket = new CommStruct();
RecievePacket = new CommStruct();
Test = new ObjectInfo();
RecievePacket.SensorData.CompassData = 0;
SendPacket.SensorData.CompassData = 0;
//SendPacket = RecievePacket;
// Create TCP server (based on MicroBridge LightWeight Server)
try
{
server = new Server(4568); //Use the same port number used in ADK Main Board firmware
server.start();
} catch (IOException e)
{
Log.e("Seeeduino ADK", "Unable to start TCP server", e);
}
server.addListener(new com.example.communicationmodulebase.AbstractServerListener() {
// Recieve handler example function
// Recieves data and sends it back
@Override
public void onReceive(com.example.communicationmodulebase.Client client, byte[] data)
{
if(UseStructFunction){
// Event handler for recieving data, the size of structs
//if (data.length < 10){
// return;
//}
// Send CommStruct
Send();
}
else{
// Event handler for recieving data, the size of the desired data to
// be recieved
if (data.length < 10){
return;
}
//For this example convert recieved data to char array before sending back
String str = new String(data); //using the platform's default charset
char[] chars = str.toCharArray();
//Send buffer function, send data back
SendBuffer(chars, 28);
}
}
});
}
// Send buffer function
public void SendBuffer(char Buffer[], int Size){
// Declare and init a byte array
byte ByteBuffer[] = new byte[Size];
// Fill byte array
for(int i=0; i < Size; i++){
ByteBuffer[i] = (byte) Buffer[i];
}
try
{
// Send byte array
server.send(ByteBuffer);
}
catch (IOException e)
{
Log.e("USBCommunicator", "problem sending TCP message", e);
}
}
public static byte[] toByteArray(CommStruct obj) throws IOException {
byte[] bytes = null;
ByteArrayOutputStream bos = null;
ObjectOutputStream oos = null;
try {
bos = new ByteArrayOutputStream();
oos = new ObjectOutputStream(bos);
oos.writeObject(obj);
oos.flush();
bytes = bos.toByteArray();
} finally {
if (oos != null) {
Log.i(TAG, "not null");
oos.close();
}
if (bos != null) {
bos.close();
Log.i(TAG, "not null");
}
}
return bytes;
}
// Send struct function
public void Send(){
try
{
// First convert the CommStruct to a byte array
// Then send the byte array
server.send(toByteArray(SendPacket));
}
catch (IOException e)
{
Log.e("USBCommunicator", "problem sending TCP message", e);
}
}
}