Develop Reference

How to check for DolbyDigtal (AC3) support on device?

I'm trying to understand: is there a way to check if Android device supports DolbyDigital (AC3).
I found a broadcast action ACTION_HDMI_AUDIO_PLUG that indicates wether HDMI connected or not. Also it sends an array of all the supported encodings via the value EXTRA_ENCODINGS. But, as I understand, those are the values that the TV supports, not the Android device itself.

How to know if my App is connected to a device using BLE in Flutter?.. when app is the beacon

So my android app is behaving as a beacon, means, it will be advertising and other BLE devices will be connecting to it. Well, this is how our project is working so please don't raise questions on this as why am i using my app as a beacon and not as a scanner. Anyways, It behaves as a beacon and starts advertising and now I want to know that if a device connected to it. I cant find a way how to do this.
Of course, I am using this flutter package. beacon_broadcast 0.3.0
This is my code.
void startAdvertising() {
BeaconBroadcast beaconBroadcast = BeaconBroadcast();
beaconBroadcast
.setUUID(advertisingUUID)
.setMajorId(1)
.setMinorId(100)
.start();
}

First, Flutter is just a UI toolkit and has no support for other system APIs such as Bluetooth.
You should therefore look what the official Android APIs offer in the first place. Usually when using BluetoothLeAdvertiser for advertising, one often also adds an instance of BluetoothGattServer in order to handle connections. If you have created a BluetoothGattServer using openGattServer, you will get a onConnectionStateChange callback whenever a device connects or disconnects. So that answers your question how an Android app can get notified when a device connects. You probably also want to use the same API to add a GATT service so that the other device can communicate with your app. Other alternatives is to use the GATT client API if it's the other device that has a GATT server, or you might want to use the L2CAP CoC API.
Note that if Bluetooth is turned off/disabled/restarted, your BluetoothGattServer object will automatically die and you need to recreate it. To get notified when this happens, use a state change intent receiver for BluetoothAdapter.ACTION_STATE_CHANGED as explained in this example https://stackoverflow.com/a/9694138/556495 to recreate your BluetoothGattServer (and advertiser) when state is changed to STATE_ON.
Now, since you want to use Flutter but Flutter uses Dart, you cannot directly consume the Android APIs. Instead you need to write a bridge/plugin, to bridge your Dart code and Java code. See https://docs.flutter.dev/development/platform-integration/platform-channels for a tutorial how to do this. If you're lucky, someone else might have already created such a package that does exactly what you want. Unfortunately, the beacon_broadcast package you found, only implements BluetoothLeAdvertiser and not BluetoothGattServer, as can be seen by the source code here: https://github.com/pszklarska/beacon_broadcast/tree/master/android/src/main/kotlin/pl/pszklarska/beaconbroadcast.

Determine Bluetooth version for a specific session

I'm writing a P2P communication app between Android and Windows devices, that relies on Bluetooth as the underline communication channel. I would like to check the version of the Bluetooth protocol being used for each session (i.e. 2.x, 4.0, 4.1, 4.2, etc), in order to make security decisions accordingly (2.x is not very secure, 4.0 is more secure, 4.1 is most secure, etc).
How can that be achieved using API, on either Windows or Android? I'll have to check that for each session and session, because to my understanding, the Bluetooth version is determined as the minimum capability for both parties.

First, the Bluetooth version after 2.1 SSP, e.g. 2.1,3.0,4.x, is basically same secure(however if you are talking about LE security that's another story), you do not need judge the LMP version actually.
Unfortunately Android does not export the remote version to apps, the lower level(Bluedroid) "BTM_ReadRemoteVersion", this function can get remote LMP version.
Your understanding is partial right, "Bluetooth version is determined as the minimum capability for both parties.", both host and controller's capability was defined by their minimum versions.

I found a way to determine the version using Android logcat. During BT connection, I look for this line:
bt_btif_dm: remote version info [aa:bb:cc:dd:ee:ff]: 8, 2, 100
The first digit (8) is the LMP version, which corresponds to a Core Bluetooth version. (In this case, 8 means Bluetooth 4.2)
This does not solve my problem completely, because starting at Android JB an app cannot read the logcat anymore (except for its own logs). However, this is a good start... will update if I find anything else.

try this
BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Set<BluetoothDevice> Devices = mBluetoothAdapter.getBondedDevices();
List<String> s = new ArrayList<String>();
for(BluetoothDevice bt : pairedDevices)
s.add(bt.getVersion());

Android JellyBean and P2P support

I am analysing Android JellyBean 4.3 source code.I could find the varialbe p2p_supported in HAL layer for Wi-Fi Direct support. In the below code snippet from wifi_ath.c
int wifi_start_supplicant(int p2p_supported)
{
if (p2p_supported)
{
strcpy(supplicant_name, P2P_SUPPLICANT_NAME);
strcpy(supplicant_prop_name, P2P_PROP_NAME); // for P2P support
.......................
}
else {
strcpy(supplicant_name, SUPPLICANT_NAME);
strcpy(supplicant_prop_name, SUPP_PROP_NAME); //for station support
}
The values of the macros are:
P2P_SUPPLICANT_NAME = p2p_supplicant ,P2P_PROP_NAME= init.svc.p2p_supplicant
SUPPLICANT_NAME=wpa_supplicant ,SUPP_PROP_NAME=init.svc.wpa_supplicant
Even while connecting in station mode the if part is getting executed and I could not make the WiFi up. Where in the code exactly p2p_supported variable is enabled and disabled so that both the P2P and Wi-Fi works smoothly?

From Jelly Bean(4.1) you only need to turn WiFi on to use WiFi Direct functionality, though using both together depends upon whether your chip supports it.(For that see this SO question)

Android Bluetooth Low Energy Motorola API pairing

I am working on using the BT 4.0 API that Motorola has provided with the RAZR. In one of their documents it states to use the Android API to pair before connecting and using their framework. Per their instructions I have been pairing with OS Bluetooth settings application, but it never prompts me for a key. It will pair but doesn't appear to bond, and this is critical for me.
My question is, when they say "using the Android API" is this referring to simply using the OS Bluetooth utility to pair before hand (like I have been doing), or is there some way to do it with code in my application. They reference the "createBond()" function which, to my knowledge, is not an accessible function (at least not without some squirrely libraries or reflection).
Any advice is greatly appreciated, especially anyone who has used the API successfully, if they could give an account of their process. I'm just looking for some clarity at this point :)

Lloyd,
You are correct, follow the instructions in the link you posted.
Outside of coding, when they say use the standard android api for "non-le" operations, they mean go ahead and pair the ble device the same way you would any bluetooth classic devices inside android settings -> wireless & network -> bluetooth -> scan for devices.
If the device you are using is a motorola le compatible device the ble device will be paired but not connected.
Now, in the code, you can detect this paired device through the same method of
BluetoothAdapter.getDefaultAdapter().getBondedDevices()
To double check if your Android Phone is LE compatible, run this code:
public static boolean checkBLESupport() {
boolean deviceSupportsLE;
try {
#SuppressWarnings({ "unused", "rawtypes" })
Class object = Class.forName("android.server.BluetoothGattService");
deviceSupportsLE = true;
} catch (Exception e) {
deviceSupportsLE = false;
}
return deviceSupportsLE;
}
And to double check if the bluetooth device you paired is LE, when you are looping through the bonded devices.
Check the device with this code.
if (device.getBluetoothClass() == null) {
Log.i(TAG, "This device is BLE compatible");
b = true;
} else {
Log.i(TAG, "This device is not BLE");
b = false;
}
Now for establishing connection from your LE compatible phone to your LE compatible bluetooth device, follow the Gatt service instructions under the link you posted. http://developer.motorola.com/docs/bluetooth-low-energy-api/
Take note that under this example it is connecting to a bluetooth low energy heart rate monitor.
If you are not trying to connect to the heart rate monitor with LE heart rate profile, here is a link to another Motorola document that details creating your own LE Profile to use with the GATT framework. http://developer.motorola.com/docs/bluetooth-low-energy-gatt-framework-api/
If the instructions are not clear enough at any point in either of these documents, motorola offers sample android applications using the frameworks in those documents.

I guess motorola stack has BLE support. But what i feel is that it does not pair with the devices that require bonding though It does work some sensors. I have tried with a proximity sensor that require bonding. It never gets paired though the devices is discovered with Razr which even does not with S3.
There's a helpful video here.

Late to the game, but can confirm -
If your BLE Peripheral requires bonding, Moto X - and some other older Motorola devices - MUST be paired via Bluetooth Settings prior to programmatic connection via the Android GATT interface.
If you bond via the createBond method, or reading of an encrypted characteristic, your connection will be dropped typically in under 60 seconds, despite DDMS logs that show a good bond may be established.