I am writing software for Android for communication between Arduino and Android.
The Arduino sends data using serial.println - I send the text "It works!".
The Android is receiving data in this way:
bytes = mmInStream.read(buffer);
mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer).sendToTarget();
And it displays some code instead of "it works!", more exactly it displays [B#40e3f9b8.
What is the reason and how can this problem be fixed?
You just tried to print a byte array. In Java, that just prints out the type of the object [B, followed by its address #40e3f9b8.
If you want to print the text out, use new String(bytes) to get a string from the bytearray (using the default charset), then print the string out.
You have to create a string from a byte array:
String strIncom = new String(buffer, 0, msg.arg1);
Full example with \r\n handler:
h = new Handler() {
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case RECIEVE_MESSAGE: // if receive massage
byte[] readBuf = (byte[]) msg.obj;
String strIncom = new String(readBuf, 0, msg.arg1); // create string from bytes array
sb.append(strIncom); // append string
int endOfLineIndex = sb.indexOf("\r\n"); // determine the end-of-line
if (endOfLineIndex > 0) { // if end-of-line,
String sbprint = sb.substring(0, endOfLineIndex); // extract string
sb.delete(0, sb.length()); // and clear
txtArduino.setText("Data from Arduino: " + sbprint); // update TextView
}
//Log.d(TAG, "...String:"+ sb.toString() + "Byte:" + msg.arg1 + "...");
break;
}
};
};
See full example program with apk and sources here
Related
What I have :
HC-05 Bluetooth module
Arduino promini
BPM sensors
Android studio 3.0
What I have done :
Connect the Arduino, sensors, and HC-05 bluetooth using Serial
Send the data from Arduino script
Recieve and get the data using 3rd party apps from playstore
What I wanted to do :
Get the data from arduino's to be showed in the android text view, using native coded apps (not the one from the store) using android studio.
My current code :
Arduino script :
loop(){
Serial.println("*"+String(BPM)+"#"); //BPM from sensor
delay(200)
}
And some code for connecting and pairing using Android Bluetooth Adapter, which I can't showed here full because still hard coded, but the point is :
I made a handler, which recieves incoming inputs from the serial, and at least showing them on Toast component, but still haven't managed to make it work.
h = new Handler() {
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case RECIEVE_MESSAGE:
Toast.makeText(getApplicationContext(),"Data in",Toast.LENGTH_SHORT
).show();// if receive massage
byte[] readBuf = (byte[]) msg.obj;
String strIncom = new String(readBuf, 0, msg.arg1); // create string from bytes array
sb.append(strIncom); // append string
int endOfLineIndex = sb.indexOf("\r\n"); // determine the end-of-line
if (endOfLineIndex > 0) { // if end-of-line,
String sbprint = sb.substring(0, endOfLineIndex); // extract string
sb.delete(0, sb.length()); // and clear
sensorView0.setText("Data from Arduino: " + sbprint); // update TextView
btnOff.setEnabled(true);
btnOn.setEnabled(true);
}
//Log.d(TAG, "...String:"+ sb.toString() + "Byte:" + msg.arg1 + "...");
break;
}
};
};
I also have a class :
private class ConnectedThread extends Thread {
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket) {
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the input and output streams, using temp objects because
// member streams are final
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
byte[] buffer = new byte[256]; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
try {
Toast.makeText(getApplicationContext(),"Masuk ke handler private class",Toast.LENGTH_SHORT
).show();
// Read from the InputStream
bytes = mmInStream.read(buffer); // Get number of bytes and message in "buffer"
h.obtainMessage(RECIEVE_MESSAGE, bytes, -1, buffer).sendToTarget(); // Send to message queue Handler
} catch (IOException e) {
break;
}
}
}
}
Which I think calls for the handler to read the message, but haven't managed to make it work.
I wanted to at least show the message to the Toast, or TextView, but haven't got a clear answer this last 3 weeks.
So anyone who can help will be appreciated.
I am trying to send audio file via Bluetooth using the sample BluetoothChat code.
I have created a class that converts audio into bytes and vise-versa.
Here are the modifications I have made in the sample code
private void sendMessage(String message) {
// Check that we're actually connected before trying anything
if (mChatService.getState() != BluetoothChatService.STATE_CONNECTED) {
Toast.makeText(getActivity(), R.string.not_connected, Toast.LENGTH_SHORT).show();
return;
}
// Check that there's actually something to send
if (message.length() > 0) {
// Get the message bytes and tell the BluetoothChatService to write
byte[] send = message.getBytes();
//Convert noti.mp3 into byte array (noti.mp3 is an audio file I am using for testing)
try{send = Converter.convertAudioToBytes(path+"noti.mp3");}
catch(Exception e){Logger.append("Error while converting audio into bytes", e);}
mChatService.write(send);
// Reset out string buffer to zero and clear the edit text field
mOutStringBuffer.setLength(0);
mOutEditText.setText(mOutStringBuffer);
}
}
I am also adding some bytes at the end of the audio to identify the endOfFile on the receiving end.
On the receiving end I have updated the mHandler
//List to store bytes received from the other device
private List<Byte> list = new ArrayList<Byte>();
case Constants.MESSAGE_READ:
byte[] readBuf = (byte[]) msg.obj;
//Status for end of data
boolean endOfData = false;
//Add bytes to the Array list
for(int i=0;i<msg.arg1;i++){list.add(readBuf[i]);}
// construct a string from the valid bytes in the buffer
String readMessage = new String(readBuf, 0, msg.arg1);
mConversationArrayAdapter.add(mConnectedDeviceName + ": " + readMessage);
//Check if the received message contains this string
//Also check if the length of the data is less than 990
if(readMessage.contains("END OF AUDIO FILE") && msg.arg1<990){
endOfData = true;
}
//Check if all the data has been received
if(endOfData)
{
try{
Converter.convertBytesToAudio(list,path);
mConversationArrayAdapter.add(mConnectedDeviceName + ": Audio saved!");
}
catch(Exception e){
Logger.append("Error while converting bytes to audio", e);
}
finally{
list.clear();
}
}
break;
The code works fine for small audio files but when I send a file that is bigger than 3KB it does not properly receive the data and does not transfer it to audio properly.
I tried to send some long text like this
String str = "Message number ";
for(int i=0;i<1000;i++){message += str+i+" ,\n";}
byte[] send = message.getBytes();
mChatService.write(send);
on the receiving end I noticed, the messages received are not synchronized.
Can someone please help me solve this issue, or any other way to transfer audio messages via Bluetooth. I am trying to do something like WhatsApp audio messages but via Bluetooth.
Any help is appreciated.Thanks
Still waiting for an answer :( Please help
I am sending data from an arduino through a Bluetooth module. I am simply streaming different integers;
int bluetoothData;
//give value to bluetoothData
Serial1.println(bluetoothData);
In my Android code, I have a Bluetooth socket that receives the data from the arduino. The data is taken care of by a Handler. And here lies the problem, sometimes the data is misread. For instance, I am sending '100', but instead the Handler saves in my database '000' or I send '194' and what is read is '994'. Sometimes such a reading mistake would occur once in every 15. Sometimes there will not be any mistake at all. Does someone know what may the reason be? Is it some hardware malfunction of the bluetooth module, is it the way I am reading the data, etc. Here is the Android code for the Thread receiving data:
final int RECIEVE_MESSAGE = 1;
...
mmInStream = socket.getOutputStream();
byte[] buffer = new byte[256]; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
bytes = mmInStream.read(buffer);
h.obtainMessage(RECIEVE_MESSAGE, bytes, -1, buffer).sendToTarget();
}
Here is the code for the handler itself:
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case RECIEVE_MESSAGE:
byte[] readBuf = (byte[]) msg.obj;
String strIncom = new String(readBuf, 0, msg.arg1);
sb.append(strIncom);
int endOfLineIndex = sb.indexOf("\r\n");
if (endOfLineIndex > 0) {
String sbprint = sb.substring(0, endOfLineIndex);
sb.delete(0, sb.length());
btData = Integer.parseInt(sbprint);
M = btData;
insert = mDataBaseHelper.insert(M,DataBaseHelper.TABLE_Temp);
}
I am building an Android application to communicate with my NR-42 bluetooth device. I am able to connect to the bluetooth and send data to the device which is a PIC18F but I am not able to receive bluetooth data from my device to my android phone.
I am following this example http://solderer.tv/data-transfer-between-android-and-arduino-via-bluetooth/comment-page-1/
When I use tera-term it shows me that the bluetooth module is doing what it is suppose to do, but I can't get the data in my textViews. I am trying to send float data. I am new to android but the issue is happening here I assume.
h = new Handler() {
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case RECIEVE_MESSAGE: // if receive massage
byte[] readBuf = (byte[]) msg.obj;
String strIncom = new String(readBuf, 0, msg.arg1); // create string from bytes array
sb.append(strIncom); // append string
int endOfLineIndex = sb.indexOf("\r\n"); // determine the end-of-line
if (endOfLineIndex > 0) { // if end-of-line,
String sbprint = sb.substring(0, endOfLineIndex); // extract string
sb.delete(0, sb.length()); // and clear
txtArduino.setText("Data from Arduino: " + sbprint); // update TextView
btnOff.setEnabled(true);
btnOn.setEnabled(true);
}
//Log.d(TAG, "...String:"+ sb.toString() + "Byte:" + msg.arg1 + "...");
break;
}
};
};
"
The input stream is being read here."
public void run() {
byte[] buffer = new byte[256]; // 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); // Get number of bytes and message in "buffer"
h.obtainMessage(RECIEVE_MESSAGE, bytes, -1, buffer).sendToTarget(); // Send to message queue Handler
Log.d(TAG, "sent handler");
} catch (IOException e) {
break;
}
}
}
Has anyone come across this issue or can help me out?
Thanks
I am using Bluetooth Chat sample app from Android website. I want to pass the complete incoming message, (message format included in the code below as this website is parsing the message for me which is my job in the code as well, to a function which removes the tags and extracts message name and value and uses it for further action. The readMessage string (in the switch case Message_Read) sends selected characters and omits few special characters. Following is the code from Bluetooth Chat app (from Android website).
I am not able to receive the complete message in the format which I have mentioned in the code. It gets displayed in multiple lines and many characters get deleted. Any suggestion why this is happening?
// The Handler that gets information back from the BluetoothChatService
private final Handler mHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MESSAGE_STATE_CHANGE:
if(D) Log.i(TAG, "MESSAGE_STATE_CHANGE: " + msg.arg1);
switch (msg.arg1) {
case BluetoothChatService.STATE_CONNECTED:
mTitle.setText(R.string.title_connected_to);
mTitle.append(mConnectedDeviceName);
mConversationArrayAdapter.clear();
break;
case BluetoothChatService.STATE_CONNECTING:
mTitle.setText(R.string.title_connecting);
break;
case BluetoothChatService.STATE_LISTEN:
case BluetoothChatService.STATE_NONE:
mTitle.setText(R.string.title_not_connected);
break;
}
break;
case MESSAGE_WRITE:
byte[] writeBuf = (byte[]) msg.obj;
// construct a string from the buffer
String writeMessage = new String(writeBuf);
mConversationArrayAdapter.add("Me: " + writeMessage);
break;
case MESSAGE_READ:
byte[] readBuf = (byte[]) msg.obj;
// construct a string from the valid bytes in the buffer
String readMessage = new String(readBuf, 0, msg.arg1);
mConversationArrayAdapter.add(mConnectedDeviceName+": " + readMessage);
//Make sure there is a received message. Extract it's name and value
//int msgLen = readMessage.length();
//if( msgLen!= 0)
// Message format is <MSG><N>shiftDirection<!N><V>1<!V><!MSG>
if (readBuf.equals("<MSG><N>.*<!N><V>.*<!V><!MSG>"))
extractData(readMessage);
else mTitle.setText(R.string.floor_it);
break;
case MESSAGE_DEVICE_NAME:
// save the connected device's name
mConnectedDeviceName = msg.getData().getString(DEVICE_NAME);
Toast.makeText(getApplicationContext(), "Connected to "
+ mConnectedDeviceName, Toast.LENGTH_SHORT).show();
break;
case MESSAGE_TOAST:
Toast.makeText(getApplicationContext(), msg.getData().getString(TOAST),
Toast.LENGTH_SHORT).show();
break;
}
}
};
The part of the code which reads the incoming stream of bytes into a buffer and passes the buffer object for display.
public void run() {
Log.i(TAG, "BEGIN mConnectedThread");
byte[] buffer = new byte[1024];
int bytes;
// Keep listening to the InputStream while connected
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
//String Incoming = new String(buffer);
//Pass "Incoming" instead of "buffer"
// Send the obtained bytes to the UI Activity
mHandler.obtainMessage(BluetoothChat.MESSAGE_READ, bytes, -1, buffer)
.sendToTarget();
} catch (IOException e) {
Log.e(TAG, "disconnected", e);
connectionLost();
break;
}
}
}
I think the problem is, that case MESSAGE_READ: is not only called if a complete Packet is received, it is also called if a small fragment is received. So you should place the readMessage in a separate buffer (i.e. mNewBuf += readMessage) check the mNewBuf has a complete packet in it. If so, you parse your message and after that you clear your buffer. It worked for me.
if (readBuf.equals("<MSG><N>.*<!N><V>.*<!V><!MSG>"))
extractData(readMessage);
equals() doesn't apply regular expressions. If you want to match .*, use classes from java.util.regex to help you.
I was having the same issue, and I'm not 100% this will always work but I found this on the javadoc:
read(byte[] b, int off, int len)
Reads up to len bytes of data from the input stream into an array of bytes.
If you know how many bytes you are expecting then you could try using
bytes = mmInStream.read(buffer, 0, lengthYouWant);
However, this wouldn't work if your incoming data is variable in length.