客户端方法仅在第一次调用时正常工作

Question

我在客户端有一个方法，当服务器发送<PING>消息时，它会将字符串<PING>发送到服务器。该方法称为parseMessage(String message)。出于某种原因，它只识别在服务器第一次发送此消息时发送了<PING>消息。我知道服务器正在正确发送邮件，因为publishProgress()正确地将其附加到arrayList并显示在屏幕上。

任何人都可以解释造成这种行为的原因吗？以下是相关代码：

public class connectTask extends AsyncTask<String,String,TCPClient> {

    @Override
    protected TCPClient doInBackground(String... message) {

        //we create a TCPClient object and
        mTcpClient = new TCPClient(new TCPClient.OnMessageReceived() {
            @Override
            //here the messageReceived method is implemented
            public void messageReceived(String message) {
                //this method calls the onProgressUpdate
                publishProgress(message);

                parseMessage(message);
            }
        });

        mTcpClient.run();

        return null;
    }

    @Override
    protected void onProgressUpdate(String... values) {
        super.onProgressUpdate(values);

        //in the arrayList we add the messaged received from server
        arrayList.add(values[0]);
        // notify the adapter that the data set has changed. This means that new message received
        // from server was added to the list
        mAdapter.notifyDataSetChanged();
    }

    private void parseMessage(String theMessage)
    {
        if (theMessage.equals("<PING>"))
        {
            if (mTcpClient != null)
            {
                mTcpClient.sendMessage("<PING>");   
            }
        }
        else
        {
            mTcpClient.sendMessage(theMessage); 
        }
    }
}