Develop Reference

Connect to specific Bluetooth device with a click

I'm trying to connect to a specific device using my Android APP, until now what I was able to do is get the paired items doing this :
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Set < BluetoothDevice > pairedDevices = bluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
for (BluetoothDevice device: pairedDevices) {
mDeviceName.add(device.getName());
mDeviceMAC.add(device.getAddress());
}
}
bluetoothClass.setDeviceName(mDeviceName);
bluetoothClass.setDeviceMac(mDeviceMAC);
Where I get the MAC and the Device name of all of my paired devices. The thing that I would like to do is when I select one it connects to the Bluetooth device.
EXAMPLE
On a Samsung S4 when I turn on the Bluetooth it popups a Dialog whitch contains all of my paired devices and when I click on anyone it connects (I've i'm able to ...) so basically I want to do this, since now I've been getting the paired devices (I don't know if it's the best way to get that but it does) and then when user click on anyone it connects to the device.
It's something like this question but it's unfortunately unanswered.

It's impossible to give you an example within this format, so I have provided you
with a good sample and helpful links to help you understand the sample.
I recommend you follow the steps I have provided and then, when you have
specific problems, you can bring it here, with the code snippet you are having
difficulty with.
I recommend you use download this sample code:
http://developer.android.com/samples/BluetoothChat/index.html
If you haven't already, it's good to study this:
http://developer.android.com/reference/android/bluetooth/BluetoothDevice.html
This is a good tutorial and they have many tutorials:
http://www.tutorialspoint.com/android/android_bluetooth.htm
You will need the following permissions in your manifest:
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
This is one intent that is advisable to use, to check to see if BT is enabled:
if (!mBluetoothAdapter.isEnabled()) {
android.content.Intent enableIntent = new android.content.Intent(
android.bluetooth.BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
}
and to make your device discoverable to other devices:
if (mBluetoothAdapter.getScanMode() !=
android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
android.content.Intent discoverableIntent =
new android.content.Intent(
android.bluetooth.BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
discoverableIntent.putExtra(
android.bluetooth.BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION,
300); // You are able to set how long it is discoverable.
startActivity(discoverableIntent);
}
As I mentioned in my answer here:
You can avoid using an intent to search for paired devices. When
connecting to a device that is not paired, a notification will pop up
asking to pair the devices. Once paired this message should not show
again for these devices, the connection should be automatic (according
to how you have written your program).
I use an intent to enable bluetooth, and to make my device
discoverable, I then set up my code to connect, and press a button to
connect. In your case, you will need to ensure your accessories are
discoverable also. In my case I use a unique UUID, and both devices
must recognise this to connect. This can only be used if you are
programming both devices, whether both are android or one android and
one other device type.
You will need to understand how to use sockets, this is how the devices communicate.
I recommend studying these two links:
http://developer.android.com/reference/android/bluetooth/BluetoothSocket.html
http://developer.android.com/reference/android/bluetooth/BluetoothServerSocket.html
Sockets are used to set up connections between devices. There will be a server socket and device sockets (determined by many factors, the programmer, the actual devices). The server socket listens for incoming connections, when a connection is accepted the devices connect, each with a simple socket.
I am not sure how much you know about threading.
The connection needs to be managed with threads:
http://developer.android.com/guide/components/processes-and-threads.html
http://android-developers.blogspot.com.au/2009/05/painless-threading.html
The connection between the devices is managed on threads separate from the User
Interface thread. This is to prevent the phone from locking up while it is
setting up, seeking and making a BT connection.
For instance:
AcceptThread - the thread that listens for a connection and accepts the connection (via the serversocket). This thread can run for an extended time waiting for a device to connect with.
ConnectThread - the thread that the device connecting to the server uses to connect to the serversocket.
ConnectedThread - this is the thread that manages the connection between both sockets.
Let me know if this helps you.

Intent for change in preferred network

Is there any intent generated when the preferred network is changed on android?
Though WIFI has the higher priority when both Mobile data and WIFI are turned on.but it can be changed using this statement
connectivityManager.setNetworkPreference(ConnectivityManager.TYPE_MOBILE);
However,if I query preferred network immediately after the above statement using
connectivityManager.getNetworkPreference()
I still get ConnectivityManager.TYPE_WIFI as return value.
So it seems that setNetworkPreference doesn't change preferred network immediately.
My question,
Is there any intent generated for change in network preference?

Create a broadcast receiver listening for:
<action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
See
Android, How to handle change in network (from GPRS to Wi-fi and vice-versa) while polling for data for an example.

get bluetooth device leave the connection

I have a bluetooth device , I want to know how to obtain the method when connected Bluetooth device is out of range
like code
//if bluetooth is Not in the range of connection
{
}
Please give me some solution

To check whether a bluetooth device is connected or not you can use intent filters to listen to the ACTION_ACL_CONNECTED, ACTION_ACL_DISCONNECT_REQUESTED, and ACTION_ACL_DISCONNECTED broadcasts. For more details please check this post How to programmatically tell if a Bluetooth device is connected? (Android 2.2)

There is no internal method like DeviceNotInRange() {} hence you need to work it out by creating your customized method. You need to create a method that keep searching on a regular interval and when device is not in range, you can raise an Alert or sound for intimation.

Android bluetooth: how to poll for connections/disconnections

I need to continuously poll for getting bluetooth devices connections/disconnections in my activity to update a listView with the currenctly available devices.
I use btAdapter.startDiscovery() but it is not permanent ... how can i correctly get the on/off events for the devices?

I would suggest using a broadcastreceiver to listen for the specific events you are talking about. You could even fire off another discovery mode after it comes out of its current discovery mode to have it keep scanning
BluetoothAdapter.ACTION_DISCOVERY_FINISHED
BluetoothDevice.ACTION_ACL_CONNECTED
BluetoothDevice.ACTION_ACL_DISCONNECTED
You can use the intent extra's to be able to get the name (ect) from the device that connects
I would read http://developer.android.com/guide/topics/wireless/bluetooth.html and
http://developer.android.com/reference/android/content/BroadcastReceiver.html

Android 2.1 Detect Bluetooth audio connect/disconnect

I'm scratching my head trying to find a way to detect bluetooth headset connect and disconnect events for Android 2.1. I see in API Level 11 that there are some explicit ones, but how do I do it in API level 7? I just want to know when the user connects or disconnects a headset or car stereo capable of playing audio, so that I can pause the sounds I'm playing.

There is no public APIs,
This answer might help where the author used private APIs using reflections.
The author has also posted a comment on how he got it to work.

This looks like a good option to detect bluetooth connect/disconnect.
If that didn't work, another good option is to set a timer in a service that calls AudioManager.isBluetoothA2dpOn() to check if the bluetooth is connected or disconnected.

Not sure if this works in 2.1, but it works in 2.2 and 2.3.
It will capture Bluetooth-Headset connection state changes:
Declare the following intent-filter
<intent-filter >
<action android:name="android.bluetooth.headset.action.AUDIO_STATE_CHANGED" />
</intent-filter>
and in your Receiver in onReceive check for:
if ("android.bluetooth.headset.action.AUDIO_STATE_CHANGED".equals(intent.getAction())) {
headsetAudioState = intent.getIntExtra("android.bluetooth.headset.extra.AUDIO_STATE", -2);
}
and save the int as a static variable. Access it anytime you want to know if BT audio is connected(1) / disconnected(0). Not pretty, but gets the job done.
Also check out:
https://github.com/android/platform_frameworks_base/blob/gingerbread/core/java/android/bluetooth/BluetoothHeadset.java

You have to setup a BroadcastReceiver for android.bluetooth.headset.action.STATE_CHANGED action. The Intent's extra android.bluetooth.headset.extra.STATE contains current state (disconnected, connecting, connected). More info the Android source code