I'm developing an app where I need to send the values of 3 seekbars via bluetooth. All the bluetooth method I've developed is based on the bluetoothChat example. The app communicates well sending characters, but as i said, i need to send the value of 3 seekbars.
So, I'm creating a sending function to send these 3 values in one string, but i think that i'm doing wrong the cast because i'm getting an error and the logcat refers my to this point.
This is the code, need to mention that the "savedProgressX" values are int type and have the current value of the seekbar, and the "sendX" values are textview type that I've created only to save these values:
public void sendValues() {
send1 = Integer.toString(savedProgress1);
send2 = Integer.toString(savedProgress2);
send3 = Integer.toString(savedProgress3);
/**Set the seekbars values into a string*/
String message = send1+":"+send2+":"+send3+"\n";
//String[] values = message.split(":");
//for (String value : values) {
//int number = Integer.valueOf(value);
//}
/**Check that we're actually connected before trying anything*/
if (GlobalVar.mTransmission.getState() != GlobalVar.STATE_CONNECTED) {
Toast.makeText(this, R.string.not_connected, Toast.LENGTH_SHORT).show();
return;
}
/**Get the message bytes and tell the Transmission to write*/
byte[] send = message.getBytes();
GlobalVar.mTransmission.write(send);
/**Reset out string buffer to zero*/
GlobalVar.mOutStringBuffer.setLength(0);
}
Related
I am using arduino to develop a small IoT project. Till now everything is working fine.
The steps of the projects are:
Create an XML String from sensor reading
Send the XML as POST to the server.
The odd thing is that the first three trials work perfectly. However, after that, the string holding the XML becomes empty.
Below is a portion of the code:
void loop()
{
while (Serial3.available()>0)
{
char c = Serial3.read();
if (gps.encode(c)){
createXML();
delay(1000);
if(seconds_passed==10000 && !IsXMLEmpty)
{
XML+="\n</start>";
Serial.print(XML);
Serial.print(F("Send to serveR"));
seconds_passed=0;
IsXMLEmpty=true;
String temp ="";
temp = "XML="+XML;
char *param = new char[temp.length()+1];
temp.toCharArray(param,temp.length());
Serial.println(param);
if(!postPage(serverName,serverPort,pushPage,"XML=123")) Serial.print(F("Fail "));
else Serial.print(F("Pass "));
XML="";
XML="<start>\n\t";
}
}
}
// if(data==false){ Serial.println("No data"); }
}
I thing the problem is with the String object. It might be a memory issue. Any idea?
In our company we are using IBM MQ server for message queueing. For the same queue we are putting both String and Object type data message with the help of methods WriteObject and WriteString.
The challenge is occured when it comes to consumption(read message) of queue. Since the Get data can be both Object or String we need to decide which method to use ReadString or ReadObject on the MQMessage instance. I made workaround like firstly using ReadObject method, if an exception occured then try it with ReadString.
I did not like this workaround, is there any way to identify message data type after calling MQQueue instance's Get method?
Here below you can find my workaround:
public object GetMessage(string queueName) {
MQQueueManager queueManager = new MQQueueManager("queueManagerName", "channel", "connection");
MQGetMessageOptions queueGetMessageOptions = new MQGetMessageOptions();
queueGetMessageOptions.Options = MQC.MQGMO_WAIT + MQC.MQGMO_FAIL_IF_QUIESCING + MQC.MQPMO_SYNCPOINT;
try {
queueRead = queueManager.AccessQueue(queueName, MQC.MQOO_INPUT_AS_Q_DEF + MQC.MQOO_FAIL_IF_QUIESCING);
queueMessage = new MQMessage();
queueMessage.Format = MQC.MQFMT_STRING;
queueRead.Get(queueMessage, queueGetMessageOptions);
try {
var readObject = queueMessage.ReadObject();
return readObject;
} catch (SerializationException) { } // if message in queue not a object
queueMessage.DataOffset = 0;
var stringMsg = queueMessage.ReadString(queueMessage.MessageLength);
return stringMsg;
} catch (MQException exp) {
if (exp.ReasonCode != 2033) {
log.ErrorFormat("MQException: ResonCode: {0}, {1}", exp.ReasonCode, exp.Message);
}
}
return "";
}
What a horrible design.
First off, why are you putting 2 different message types into the same queue? Bad, very bad idea. You should be using 2 different queues. What, does someone think queues are scarce or rare? You should be handing out queues like candy.
Secondly, if you really need to go with this design then you should read the MQ Knowledge Center on MQMD structure. It contains a field called 'Message Type'. Most applications use 'Message Type' to contain either 'MQMT_DATAGRAM' or 'MQMT_REQUEST' but you can set your own values starting with 'MQMT_APPL_FIRST'.
So, define a couple of constants:
public const int MY_MSG_OBJECT = MQC.MQMT_APPL_FIRST + 1;
public const int MY_MSG_STRING = MQC.MQMT_APPL_FIRST + 2;
Hence, the sending application putting a string message would do:
MQMessage sendmsg = new MQMessage();
sendmsg.Format = MQC.MQFMT_STRING;
sendmsg.MessageType = MY_MSG_STRING;
sendmsg.WriteString("This is a test message");
queue.Put(sendmsg, pmo);
and the sending application putting an object message would do:
MQMessage sendmsg = new MQMessage();
sendmsg.Format = MQC.MQFMT_NONE;
sendmsg.MessageType = MY_MSG_OBJECT;
sendmsg.WriteObject(someObject);
queue.Put(sendmsg, pmo);
The receiving application would do:
MQMessage rcvmsg = new MQMessage();
queue.Get(rcvmsg, gmo);
// Check the Message Type
if (rcvmsg.MessageType == MY_MSG_STRING)
{
readString = queue.ReadString();
}
else if (rcvmsg.MessageType == MY_MSG_OBJECT)
{
readObject = queue.ReadObject();
}
else
{
System.Console.Out.WriteLine("Error: Unknown message type.");
}
I have a Form that create a UDP object, in the UDP class a UDPClient is created and the received data is done in the BeginReceive Method using EndReceive.
When I print the string of the reveived data, after converting the byte[], to the console from within the beginreceive method, with text appended, only the received data prints not the appended text.
So it looks like the received data is incomplete.
When the string prints, the NewLine and appended "done" is not shown.
Any help would be great!!
Thanks
class Udp
{
public EventHandler _dataReceived;
public Udp()
{
int receiverPort = 1248;
UdpClient receiver = new UdpClient(receiverPort);
string discovery = "<?xml version=\"1.0\"?><ServiceQuery></ServiceQuery>";
receiver.BeginReceive(new AsyncCallback( DataReceived), receiver);
IPEndPoint end = new IPEndPoint(IPAddress.Broadcast, 1248);
receiver.Send(Encoding.ASCII.GetBytes(discovery + "\0"), discovery.Length + 1, end);
}
private void DataReceived(IAsyncResult ar)
{
UdpClient c = (UdpClient)ar.AsyncState;
IPEndPoint receivedIpEndPoint = new IPEndPoint(IPAddress.Any, 1248);
Byte[] receivedBytes = c.EndReceive(ar, ref receivedIpEndPoint);
string receivedText = ASCIIEncoding.ASCII.GetString(receivedBytes);
Console.WriteLine("\n");
if(_dataReceived != null)
{
Console.Write(receivedIpEndPoint + ": " + receivedText + Environment.NewLine + "done");
_dataReceived(receivedText, new EventArgs());
}
c.BeginReceive(new AsyncCallback(DataReceived), c);
}
}
The simplest repro I can think of for this problem is this code:
private void button1_Click(object sender, EventArgs e) {
Byte[] receivedBytes = new byte[] { 0x48, 0x65, 0x6c, 0x00, 0x6c, 0x6f };
string receivedText = Encoding.ASCII.GetString(receivedBytes);
Console.Write(receivedText + ", you won't see this");
}
Output after clicking the button several times:
HelHelHelHel
Surely you now recognize the poison-pill in the receivedBytes array, it is the presence of the 0x00 byte that causes the output string to get cut short. Nothing beyond that byte makes it into the Visual Studio Output window.
Explaining this behavior requires a pretty deep dive in how Console.Write() in a Winforms app works and how it is capable of generating output, even though your program has no console. It is a long-winded story that isn't that likely to entertain anybody so I'll punt for the short version. With the Visual Studio Hosting Process debugger option enabled, Console.Write() is equivalent to Debug.Write(). Debug output is intercepted by the DefaultTraceListener class, it pinvokes OutputDebugString() to get the text to appear in the debugger trace window. These winapi functions takes C strings, a C string is zero-terminated to indicate the end of the string.
There are several ways to fix this, the programmer's way is to convert the byte[] array content to hex:
Byte[] receivedBytes = new byte[] { 0x48, 0x65, 0x6c, 0x00, 0x6c, 0x6f };
string receivedText = BitConverter.ToString(receivedBytes);
Console.WriteLine(receivedText + ", you see this");
Output:
48-65-6C-00-6C-6F, you see this
48-65-6C-00-6C-6F, you see this
48-65-6C-00-6C-6F, you see this
Or you might want to take a better look at the data you transmit, ensuring it is actually printable text that can be properly converted with Encoding.ASCII
In the applications I'm developing I need to store data for Customer,Products and their Prices.
In order to persist that data I use RMS, but knowing that RMS doesn't support object serializing directly and since that data I read already comes in json format, I store every JSONObject as its string version, like this:
rs = RecordStore.openRecordStore(mRecordStoreName, true);
JSONArray jsArray = new JSONArray(data);
for (int i = 0; i < jsArray.length(); i++) {
JSONObject jsObj = jsArray.getJSONObject(i);
stringJSON = jsObj.toString();
addRecord(stringJSON, rs);
}
The addRecord Method
public int addRecord(String stringJSON, RecordStore rs) throws JSONException,RecordStoreException {
int id = -1;
byte[] raw = stringJSON.getBytes();
id= rs.addRecord(raw, 0, raw.length);
return id;
}
So I have three RecordStores (Customer,Products and their Prices) and for each of them I do the save as shown above to save their corresponding data.
I know this might be a possible to solution, but I'm sure there's gotta be a better implementation. Even more,considering that over those three "tables" I'm going to perform searching, sorting,etc.
In those cases, having to deserialize before proceeding to search or sort doesn't seem a very good idea.
That's why I want to ask you guys. In your experience, how do store custom objects in RMS in way that is easy to work with them later??
I really appreciate all your comments and suggestions.
EDIT
It seems that it's easier to work with records when you define a fixed max length for each field. So here's what I tried:
1) First all, this is the class I use to retrieve the values from the record store:
public class Customer {
public int idCust;
public String name;
public String IDNumber;
public String address;
}
2) This is the code I use to save every jsonObject to the record store:
RecordStore rs = null;
try {
rs = RecordStore.openRecordStore(mRecordStoreName, true);
JSONArray js = new JSONArray(data);
for (int i = 0; i < js.length(); i++) {
JSONObject jsObj = js.getJSONObject(i);
byte[] record = packRecord(jsObj);
rs.addRecord(record, 0, record.length);
}
} finally {
if (rs != null) {
rs.closeRecordStore();
}
}
The packRecord method :
private byte[] packRecord(JSONObject jsonObj) throws IOException, JSONException {
ByteArrayOutputStream raw = new ByteArrayOutputStream();
DataOutputStream out = new DataOutputStream(raw);
out.writeInt(jsonObj.getInt("idCust"));
out.writeUTF(jsonObj.getString("name"));
out.writeUTF(jsonObj.getString("IDNumber"));
out.writeUTF(jsonObj.getString("address"));
return raw.toByteArray();
}
3) This is how I pull all the records from the record store :
RecordStore rs = null;
RecordEnumeration re = null;
try {
rs = RecordStore.openRecordStore(mRecordStoreName, true);
re = rs.enumerateRecords(null, null, false);
while (re.hasNextElement()) {
Customer c;
int idRecord = re.nextRecordId();
byte[] record = rs.getRecord(idRecord);
c = parseRecord(record);
//Do something with the parsed object (Customer)
}
} finally {
if (re != null) {
re.destroy();
}
if (rs != null) {
rs.closeRecordStore();
}
}
The parseRecord Method :
private Customer parseRecord(byte[] record) throws IOException {
Customer cust = new Customer();
ByteArrayInputStream raw = new ByteArrayInputStream(record);
DataInputStream in = new DataInputStream(raw);
cust.idCust = in.readInt();
cust.name = in.readUTF();
cust.IDNumber = in.readUTF();
cust.address = in.readUTF();
return cust;
}
This is how I implemented what Mister Smith suggested(hope it's what he had in mind). However, I'm still not very sure about how to implement the searchs.
I almost forget to mention that before I made theses changes to my code, the size of my RecordStore was 229048 bytes, now it is only 158872 bytes :)
RMS is nothing of the sort of a database. You have to think of it as a record set, where each record is a byte array.
Because of this, it is easier to work with it when you define a fixed max length for each field in the record. For instance, a record could be some info about a player in a game (max level reached, score, player name, etc). You could define the level field as 4 bytes long (int), then a score field of 8 bytes (a long), then the name as a 100 bytes field (string). This is tricky because strings usually will be of variable length, but you would probably like to have a fixed max length for this field, and if some string is shorter than that, you'd use a string terminator char to delimite it. (This example is actually bad because the string is the last field, so it would have been easier to keep it variable length. Just imagine you have several consecutive fields of type string.)
To help you with serialization/deserialization, you can use DataOutputstream and DataInputStream. With these classes you can read/write strings in UTF and they will insert the string delimiters for you. But this means that when you need a field, as you don't know exactly where it is located, you'll have to read the array up to that position first.
The advantage of fixed lengths is that you could later use a RecordFilter and if you wanted to retrieve recors of players that have reached a score greater than 10000, you can look at the "points" field in exactly the same position (an offset of 4 bytes from the start of the byte array).
So it's a tradeoff. Fixed lengths means faster access to fields (faster searches), but potential waste of space. Variable lengths means minimum storage space but slower searches. What is best for your case will depend on the number of records and the kind of searches you need.
You have a good collection of tutorials in the net. Just to name a few:
http://developer.samsung.com/java/technical-docs/Java-ME-Record-Management-System
http://developer.nokia.com/community/wiki/Persistent_Data_in_Java_ME
I have been using the ABPeoplePickerNavigationController in a project, written in MonoTouch, to pick a specific email address or phone number of a contact.
The code set a delegate, and in the delegate I implemented the ShouldContinue method, and retrieved the contact using the Handle property of all contacts. Unfortunately, it looks like something changed, or that I used undocumented features, or that I was simply lucky, because now when I'm in the process of updating the app for iPhone 5, the code no longer works.
Edit: Ok, my initial thoughts was that this was caused by changes in MonoTouch, since there has been quite a few updates since I last worked on this app. However, I now removed it from my device and downloaded the version I have on the app store, and it crashes in the same manner, null reference exception.
This means it is an iOS upgrade that made my code non-functional.
The goal of my code:
Pick a person's specific email address, not just the person, but navigating into the details of the person, and selecting a specific email address or telephone number.
The below code deals with phone numbers only, the email code looks 95% similar.
Here is the code that constructs the picker:
var picker = new ABPeoplePickerNavigationController();
picker.Init();
picker.DisplayedProperties.Clear();
picker.DisplayedProperties.Add(ABPersonProperty.FirstName);
picker.DisplayedProperties.Add(ABPersonProperty.Phone);
var del = new PhonePickerDelegate();
picker.Delegate = del;
Here is the delegate class:
private class PhonePickerDelegate : ABPeoplePickerNavigationControllerDelegate
{
public override bool ShouldContinue(ABPeoplePickerNavigationController peoplePicker, IntPtr selectedPerson, int propertyId, int identifier)
{
peoplePicker.DismissModalViewControllerAnimated(true);
// THE NEXT LINE IS THE ONE THAT NO LONGER WORKS
var contact = peoplePicker.AddressBook.SingleOrDefault(s => s.Handle == selectedPerson) as ABPerson;
using (var phones = contact.GetPhones())
{
int index = phones.GetIndexForIdentifier(identifier);
var phone = phones.GetValues()[index];
var name = (contact.FirstName + " " + contact.MiddleName).Trim() + " " + contact.LastName;
Selected(name + ": " + phone);
}
return false;
}
public override void Cancelled(ABPeoplePickerNavigationController peoplePicker)
{
peoplePicker.DismissModalViewControllerAnimated(true);
}
}
Unfortunately this code no longer finds the correct contact, as none of the contacts has a Handle value that corresponds to the selectedPerson IntPtr value.
My questions are these:
How can I fix the above code?
Can I fix the above code?
Is there some other class/method/delegate/event or whatnot I should be using instead?
You could do something like the following:
Note that AppDelegate.navigation would be your current NavigationController
using MonoTouch.AddressBookUI;
using MonoTouch.AddressBook;
ABPeoplePickerNavigationController _contactController = new ABPeoplePickerNavigationController ();
AppDelegate.navigation.PresentViewController (_contactController, true, null);
_contactController.Cancelled += delegate {
AppDelegate.navigation.DismissViewController (true, null);
return;
};
_contactController.SelectPerson += delegate(object sender, ABPeoplePickerSelectPersonEventArgs e) {
_importedContact = e.Person;
AppDelegate.navigation.DismissViewController (true, delegate {
// What to do when you dismiss the picker here.
});
};
e.Person is only going to give you the whole contact. You would want to do something like:
e.Person.GetEmails().FirstOrDefault
Hope this helps