A2DPProfile 定义了高质量音频数据传输的协议和过程，包括立体声和单声道数据的传输。这里的高质量音频指的是单声道(Mono)和立体声(Sterco) 的音频，主要区别于蓝牙 SCO 链路上传输的普通语音。A2DP 的典型应用是将音乐播放器的音频数据发送到耳机或音箱。
由于蓝牙提供的带宽较窄，音频数据可能需要进行有效的压缩才能保证接收端的实时播放。
目前 A2DP 只定义了点对点的音频传输，没有定义广播式的音频传输，可能是由于速率的原因。
A2DP 建立在 AVDTP 传输协议的基础之上，AVDTP 规定了链接是如何建立的，连接建立好之后，音频数据经过压缩之后，便可以收发了。
直接上代码的吧，有很详细的注释，各位看官应该看起来问题不大：
public class BluetoothChatA2dpService {
private BluetoothA2dp mA2dp;
private String TAG = "BluetoothChatA2dpService";
private BluetoothDevice mConnectDevice;
private BluetoothAdapter mBtAdapter;
private static Context mContext;
private static BluetoothChatA2dpService bluetoothA2dpChatService;
private int callBackState = 0;
public interface OnConnectionListener {
void onConnectionStateChanged(
BluetoothDevice bluetoothDevice, int state);
}
public interface OnBluetoothA2dpReadyListener {
void onBluetoothA2dpReady();
}
private OnBluetoothA2dpReadyListener onBluetoothA2dpReadyListener;
public void setOnBluetoothA2dpReadyListener(OnBluetoothA2dpReadyListener listener) {
onBluetoothA2dpReadyListener = listener;
}
private OnConnectionListener onConnectionListener;
public void setOnConnectionListener(OnConnectionListener listener) {
onConnectionListener = listener;
}
private BluetoothChatA2dpService() {
initReceiver();
initBluetooth();
}
public int getBluetoothDeviceA2dpStatus(BluetoothDevice bluetoothDevice) {
if (mA2dp == null) {
return -2;
}
return mA2dp.getConnectionState(bluetoothDevice);
}
private void initBluetooth() {
mBtAdapter = BluetoothAdapter.getDefaultAdapter();
if (!mBtAdapter.isEnabled()) {
return;
}
//获取A2DP代理对象
mBtAdapter.getProfileProxy(mContext, mListener, BluetoothProfile.A2DP);
}
private void initReceiver() {
//广播接收者监听状态
IntentFilter filter = new IntentFilter(BluetoothA2dp.
ACTION_CONNECTION_STATE_CHANGED);
filter.addAction(BluetoothA2dp.ACTION_PLAYING_STATE_CHANGED);
mContext.registerReceiver(mReceiver, filter);
}
public static BluetoothChatA2dpService getInstance(Context context) {
if (context != null) {
mContext = context.getApplicationContext();
if (bluetoothA2dpChatService == null) {
bluetoothA2dpChatService = new BluetoothChatA2dpService();
}
} else {
throw new RuntimeException("The context is null!");
}
return bluetoothA2dpChatService;
}
private BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
//A2DP连接状态改变
if (action != null) {
if (action.equals(BluetoothA2dp.ACTION_CONNECTION_STATE_CHANGED)) {
int state = intent.getIntExtra(BluetoothA2dp.EXTRA_STATE, BluetoothA2dp.STATE_DISCONNECTED);
callBackA2dpConnectState(state);
} else if (action.equals(BluetoothA2dp.ACTION_PLAYING_STATE_CHANGED)) {
//A2DP播放状态改变
int state = intent.getIntExtra(BluetoothA2dp.EXTRA_STATE, BluetoothA2dp.STATE_NOT_PLAYING);
Log.i(TAG, "play state=" + state);
}
}
}
};
private int callBackA2dpConnectState(int state) {
if (onConnectionListener != null) {
if (mA2dp == null) {
//获取A2DP代理对象
mBtAdapter.getProfileProxy(mContext, mListener, BluetoothProfile.A2DP);
}
if (state == BluetoothA2dp.STATE_DISCONNECTED) {
getDisconnectDevices();
callBackState = ConnectionState.A2DP_DISCONNECTED;
} else if (state == BluetoothA2dp.STATE_CONNECTING) {
callBackState = ConnectionState.A2DP_CONNECTING;
} else if (state == BluetoothA2dp.STATE_CONNECTED) {
getConnectedDevices();
callBackState = ConnectionState.A2DP_CONNECTED;
} else {
callBackState = state;
}
Log.i(TAG, "connect state=" + state);
if (onConnectionListener != null) {
onConnectionListener.onConnectionStateChanged(mConnectDevice, callBackState);
}
}
return callBackState;
}
private void getConnectedDevices() {
if (mA2dp != null && mA2dp.getConnectedDevices() != null && mA2dp.getConnectedDevices().size() > 0) {
for (int i = 0; i < mA2dp.getConnectedDevices().size(); i++) {
Log.i(TAG, "connect device=" + mA2dp.getConnectedDevices().get(i));
mConnectDevice = mA2dp.getConnectedDevices().get(i);
}
}
}
private void getDisconnectDevices() {
if (mA2dp != null && mA2dp.getConnectedDevices() != null && mA2dp.getConnectedDevices().size() > 0) {
for (int i = 0; i < mA2dp.getConnectedDevices().size(); i++) {
Log.i(TAG, "connect device=" + mA2dp.getConnectedDevices().get(i));
mConnectDevice = mA2dp.getConnectedDevices().get(i);
getA2dpConnectState();
}
}
}
private BluetoothProfile.ServiceListener mListener = new BluetoothProfile.ServiceListener() {
@Override
public void onServiceDisconnected(int profile) {
Log.i(TAG, "onServiceDisconnected profile=" + profile);
if (profile == BluetoothProfile.A2DP) {
mA2dp = null;
}
}
@Override
public void onServiceConnected(int profile, BluetoothProfile proxy) {
Log.i(TAG, "onServiceConnected profile=" + profile);
if (profile == BluetoothProfile.A2DP) {
mA2dp = (BluetoothA2dp) proxy; //转换
if (onBluetoothA2dpReadyListener != null) {
onBluetoothA2dpReadyListener.onBluetoothA2dpReady();
}
}
}
};
public BluetoothDevice getCurrentConnectedA2dpDevice() {
return mConnectDevice;
}
public void connectA2dp(BluetoothDevice device) {
Log.i(TAG, "connect to device :" + device);
mConnectDevice = device;
setPriority(device, 100); //设置priority
try {
//通过反射获取BluetoothA2dp中connect方法（hide的），进行连接。
Method connectMethod = BluetoothA2dp.class.getMethod("connect",
BluetoothDevice.class);
connectMethod.invoke(mA2dp, device);
} catch (Exception e) {
e.printStackTrace();
}
}
public void disConnectA2dp(BluetoothDevice device) {
mConnectDevice = null;
setPriority(device, 0);
try {
//通过反射获取BluetoothA2dp中connect方法（hide的），断开连接。
Method connectMethod = BluetoothA2dp.class.getMethod("disconnect",
BluetoothDevice.class);
connectMethod.invoke(mA2dp, device);
} catch (Exception e) {
e.printStackTrace();
}
}
public int getPriority(BluetoothDevice device) {
int priority = 0;
if (mA2dp == null) return priority;
try {//通过反射获取BluetoothA2dp中getPriority方法（hide的），获取优先级
Method connectMethod = BluetoothA2dp.class.getMethod("getPriority",
BluetoothDevice.class);
priority = (Integer) connectMethod.invoke(mA2dp, device);
} catch (Exception e) {
e.printStackTrace();
}
return priority;
}
public void setPriority(BluetoothDevice device, int priority) {
if (mA2dp == null) return;
try {//通过反射获取BluetoothA2dp中setPriority方法（hide的），设置优先级
Method connectMethod = BluetoothA2dp.class.getMethod("setPriority",
BluetoothDevice.class, int.class);
connectMethod.invoke(mA2dp, device, priority);
} catch (Exception e) {
e.printStackTrace();
}
}
public boolean isA2dpConnect(){
if(mA2dp != null && callBackState == ConnectionState.A2DP_CONNECTED){
return true;
}
return false;
}
public boolean isNativeA2dpConnect(){
LogManager.i(TAG, "isNativeA2dpConnect = " + mBtAdapter.getProfileConnectionState(BluetoothProfile.A2DP));
if(mA2dp!= null && mBtAdapter.getProfileConnectionState(BluetoothProfile.A2DP) == BluetoothA2dp.STATE_CONNECTED){
return true;
}
return false;
}
public int getA2dpConnectState() {
int a2dpState = 0;
if (mBtAdapter.isEnabled()) {
a2dpState = mBtAdapter.getProfileConnectionState(BluetoothProfile.A2DP); // 可操控蓝牙设备，如带播放暂停功能的蓝牙耳机
LogManager.i(TAG, "getA2dpConnectState 当前a2dp状态为 = " + a2dpState);
} else {
LogManager.e(TAG, "蓝牙未开启，查询蓝牙a2dp状态失败");
}
return callBackA2dpConnectState(a2dpState);
}
}使用：
BluetoothChatA2dpService.getInstance(this).connectA2dp(device)最后祝大家国庆快乐！