@Mackovich Thank you very much and also the others who tried to help. For the sake of other people who is having same problem. this is my solution after searching for long time.
P.S one thing I want to mention, I read about "Services" and it the right way. But I did it in other simple way.
I have two activities (1) Bluetooth search activity, and (2) Direction activity.
My problem was that I tried to do all the Bluetooth stuuf in activity (1) and just send command from activity (2) to (1) which will send it to the RC Car. And this is problem because as @Mackovich said the activity may be destroyed.
What did I do to solve is?
In activity (1) I used a ListView to display the Bluetooth devices broadcasting and to get these devices info. Then use an Intent to pass these info to the activity (2). Instated of connecting and trying to send in activity (1).
Note: In order to make a Bluetooth connection you need two important information:
1. UUID (which we aleard have).
2. MAC Address of the targeted Bluetooth device. (Which we get it form activity(1)).
So, first we need Bluetooth Adapter, Array Adapter (To holed the info of devices found) and Broadcast Receiver.
//Declare Bluetooth Stuff
BluetoothAdapter mBluetoothAdapter; // Make instance of the Bluetooth
ArrayAdapter mArrayAdapter; // Array where the devices will be stored
private static final int ENABLE_BT_REQUEST_CODE = 1;
private static final int DISCOVERABLE_BT_REQUEST_CODE = 2;
private static final int DISCOVERABLE_DURATION = 300;
public static String EXTRA_ADDRESS = "Device_MAC_Address";
//In order for the bluetooth to discover the devices that broadcasting and obtain their info.
BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
// Whenever a remote Bluetooth device is found
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
// Get the BluetoothDevice object from the Intent
BluetoothDevice mBluetoothDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
// Add the name and address to an array adapter to show in a ListView
mArrayAdapter.add(mBluetoothDevice.getName() + "\n" + mBluetoothDevice.getAddress());
} else {
Toast.makeText(getApplicationContext(), "No Paired Bluetooth Devices Found.", Toast.LENGTH_LONG).show();
}
}
};
Then, after the user select one of the devices listed. We will obtain the device MAC address and send it to activity (2) to connect and send.
//Obtain the value of the item clicked as String value
String itemValue = (String) DevicesList.getItemAtPosition(position);
//Extract the MAC Address from the String value above
String MAC = itemValue.substring(itemValue.length() - 17);
// Make an intent to start next activity.
Intent i = new Intent(BluetoothActivity.this, NavigationActivity.class);
//Change the activity.
i.putExtra(EXTRA_ADDRESS, MAC); //this will be received at NavigationActivity(class) Activity
startActivity(i);
}
});
Now, We solved the problem of passing data between activities. Because there is no need foe passing data.
This was for the Problem (1) in original post.
As for problem (2).
The problem is if you used the code provided by Google. There is things you need to adjust. In the class ConnectThread insaid run method you need to define the object of the class ConnectedThread you created. By this way you will pass the BluetoothSocket variable used to connect to send data throw it.
And that also solves problem (3). And yes you need the two classes.
As I said in the Original Post I am beginner. So, I figured that what is the best way to explain to beginners is to think like one. Which in this case I am actually beginner.
I hope this is going to help someone else. And PLEASE if some find any thing in this is wrong. PLEASE tell me to correct it.
Thank you.
