收到的对象为空

Question

简单套接字客户端 - 服务器应用程序： 我把serializeble对象放在ArrayList＆lt;＆gt;中并将他发送给客户 - ＆gt;客户端获取此对象并没有。我的数组是空的。

为什么ArrayList<GameObject> arrayList = (ArrayList<GameObject>) in.readObject();为空？

class GameObject implements Serializable{
    public int CX;
    public int CY;

    public GameObject(int cx, int cy) {
        this.CX = cx; this.CY = cy;
    }
}

    public class MainActivity extends AppCompatActivity implements View.OnClickListener {
        private GameObject[] array;
        private ObjectOutputStream out;

        Server server;
        Client client;

        Button btServer;
        Button btClient;
        Button btSend;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            btServer = (Button) findViewById(R.id.btServer);
            btClient = (Button) findViewById(R.id.btClient);
            btSend = (Button) findViewById(R.id.btSend);

            btServer.setOnClickListener(this);
            btClient.setOnClickListener(this);

            array = new GameObject[5];
            for(int i = 0; i < array.length; ++i)
                array[i] = new GameObject(i, 100-i);

            btSend.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    server.send();
                }
            });
        }

        @Override
        public void onClick(View v) {
            btClient.setEnabled(false);
            btServer.setEnabled(false);
            switch (v.getId())
            {
                case R.id.btServer:
                    server = new Server();
                    server.start();
                    break;
                case R.id.btClient:
                    client = new Client();
                    client.start();
                    break;
            }

            btSend.setEnabled(true);
        }

        class Server extends Thread {
            public static final int SERVERPORT = 4444;

            public void send() {
                if(out != null)
                {
                    try
                    {
                        ArrayList<GameObject> arrayList = new ArrayList<>();
                        for(int i = 0; i < arrayList.size(); ++i)
                            if(array[i] != null) arrayList.add(array[i]);

                        out.writeObject(arrayList);
                        out.flush();
                    }
                    catch (Exception e)
                    {
                        e.printStackTrace();
                        Log.e("myLogs", e.getMessage());
                    }
                }
            }

            @Override
            public void run() {
                super.run();

                try {
                    ServerSocket serverSocket = new ServerSocket(SERVERPORT);
                    Socket client = serverSocket.accept();
                    try {
                        out = new ObjectOutputStream(client.getOutputStream());
                        ObjectInputStream in = new ObjectInputStream(client.getInputStream());
                        while (true) {
                            //ArrayList<GameObject> array = (ArrayList<GameObject>) in.readObject();
                            //if(array != null) gameMessenger.updateField(array);
                        }

                    } catch (Exception e) {
                        e.printStackTrace();
                        Log.e("myLogs", e.getMessage());
                    } finally {
                        client.close();
                    }

                } catch (Exception e) {
                    Log.e("myLogs", e.getMessage());
                }

            }
        }

        class Client extends Thread {
            public static final String SERVERIP = "192.168.1.9";
            public static final int SERVERPORT = 4444;

            @Override
            public void run() {
                super.run();
                try
                {
                    InetAddress address = InetAddress.getByName(SERVERIP);
                    Socket socket = new Socket(address, SERVERPORT);
                    try
                    {
                        ObjectInputStream in = new ObjectInputStream(socket.getInputStream());

                        while (true) {
                            ArrayList<GameObject> arrayList = (ArrayList<GameObject>) in.readObject();
                            if(array != null) {
                                for(int i = 0; i < arrayList.size(); ++i)
                                    Log.d("myLogs", String.format("%d. (%d; %d)", i, arrayList.get(i).CX, arrayList.get(i).CY));
                                Log.d("myLogs", "---");
                            }
                        }
                    }
                    catch (Exception e)
                    {
                        Log.e("myLogs", e.getMessage());
                    }
                    finally {
                        socket.close();
                    }
                }
                catch (Exception e)
                {
                    Log.e("myLogs", e.getMessage());
                }
            }
        }
    }

activity_main.xml中

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.wertyj.deleteittest.MainActivity"
    android:gravity="center_vertical|center_horizontal">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="SERVER"
            android:id="@+id/btServer"
            android:layout_centerVertical="true"
            android:layout_toRightOf="@+id/textView"
            android:layout_toEndOf="@+id/textView"
            android:layout_gravity="center_horizontal"/>

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="CLIENT"
            android:id="@+id/btClient"
            android:layout_centerVertical="true"
            android:layout_toRightOf="@+id/btServer"
            android:layout_toEndOf="@+id/btServer"
            android:layout_gravity="center_horizontal"/>

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Send"
            android:id="@+id/btSend"
            android:enabled="false"/>
</LinearLayout>
</LinearLayout>