1. 监听蓝牙设备(音频)连接状态
所有代码已测试在Android11也能正常使用 (Android SDK 30)
首先新建一个广播类 BluetoothStateReceiver
/**
* @author komine
* 监听蓝牙音频设备的连接状态
*/
class BluetoothStateReceiver : BroadcastReceiver(){
override fun onReceive(context: Context?, intent: Intent?) {
when(intent?.action){
//蓝牙已连接,如果不需要判断是否为音频设备,下面代码块的判断可以不要
BluetoothDevice.ACTION_ACL_CONNECTED -> {
val device =
intent.getParcelableExtra<BluetoothDevice>(BluetoothDevice.EXTRA_DEVICE)
?: return
//如果在Android32 SDK还需要声明 android.permission.BLUETOOTH_CONNECT权限
if (isHeadPhone(device.bluetoothClass)) {
Log.d("BluetoothStateReceiver", "蓝牙音频设备已连接")
}
}
//蓝牙状态发生改变,断开,正在扫描,正在连接
BluetoothAdapter.ACTION_STATE_CHANGED -> {
val blueState = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, 0)
if (blueState == BluetoothAdapter.STATE_OFF) {
Log.d("BluetoothStateReceiver", "蓝牙设备已断开")
}
}
}
}
companion object{
private const val PROFILE_HEADSET = 0
private const val PROFILE_A2DP = 1
private const val PROFILE_OPP = 2
private const val PROFILE_HID = 3
private const val PROFILE_PANU = 4
private const val PROFILE_NAP = 5
private const val PROFILE_A2DP_SINK = 6
}
private fun isHeadPhone(bluetoothClass: BluetoothClass?): Boolean {
if (bluetoothClass == null) {
return false
}
return if (doesClassMatch(bluetoothClass, PROFILE_HEADSET)) true else doesClassMatch(bluetoothClass, PROFILE_A2DP)
}
//系统源码拷贝
//可以参考 http://androidxref.com/9.0.0_r3/xref/frameworks/base/core/java/android/bluetooth/BluetoothClass.java
private fun doesClassMatch(bluetoothClass: BluetoothClass, profile: Int): Boolean {
return if (profile == PROFILE_A2DP) {
if (bluetoothClass.hasService(BluetoothClass.Service.RENDER)) {
return true
}
when (bluetoothClass.deviceClass) {
BluetoothClass.Device.AUDIO_VIDEO_HIFI_AUDIO, BluetoothClass.Device.AUDIO_VIDEO_HEADPHONES, BluetoothClass.Device.AUDIO_VIDEO_LOUDSPEAKER, BluetoothClass.Device.AUDIO_VIDEO_CAR_AUDIO -> true
else -> false
}
} else if (profile == PROFILE_A2DP_SINK) {
if (bluetoothClass.hasService(BluetoothClass.Service.CAPTURE)) {
return true
}
when (bluetoothClass.deviceClass) {
BluetoothClass.Device.AUDIO_VIDEO_HIFI_AUDIO, BluetoothClass.Device.AUDIO_VIDEO_SET_TOP_BOX, BluetoothClass.Device.AUDIO_VIDEO_VCR -> true
else -> false
}
} else if (profile == PROFILE_HEADSET) {
// The render service class is required by the spec for HFP, so is a
// pretty good signal
if (bluetoothClass.hasService(BluetoothClass.Service.RENDER)) {
return true
}
when (bluetoothClass.deviceClass) {
BluetoothClass.Device.AUDIO_VIDEO_HANDSFREE, BluetoothClass.Device.AUDIO_VIDEO_WEARABLE_HEADSET, BluetoothClass.Device.AUDIO_VIDEO_CAR_AUDIO -> true
else -> false
}
} else if (profile == PROFILE_OPP) {
if (bluetoothClass.hasService(BluetoothClass.Service.OBJECT_TRANSFER)) {
return true
}
when (bluetoothClass.deviceClass) {
BluetoothClass.Device.COMPUTER_UNCATEGORIZED, BluetoothClass.Device.COMPUTER_DESKTOP, BluetoothClass.Device.COMPUTER_SERVER, BluetoothClass.Device.COMPUTER_LAPTOP, BluetoothClass.Device.COMPUTER_HANDHELD_PC_PDA, BluetoothClass.Device.COMPUTER_PALM_SIZE_PC_PDA, BluetoothClass.Device.COMPUTER_WEARABLE, BluetoothClass.Device.PHONE_UNCATEGORIZED, BluetoothClass.Device.PHONE_CELLULAR, BluetoothClass.Device.PHONE_CORDLESS, BluetoothClass.Device.PHONE_SMART, BluetoothClass.Device.PHONE_MODEM_OR_GATEWAY, BluetoothClass.Device.PHONE_ISDN -> true
else -> false
}
} else if (profile == PROFILE_HID) {
bluetoothClass.deviceClass and BluetoothClass.Device.Major.PERIPHERAL == BluetoothClass.Device.Major.PERIPHERAL
} else if (profile == PROFILE_PANU || profile == PROFILE_NAP) {
// No good way to distinguish between the two, based on class bits.
if (bluetoothClass.hasService(BluetoothClass.Service.NETWORKING)) {
true
} else bluetoothClass.deviceClass and BluetoothClass.Device.Major.NETWORKING == BluetoothClass.Device.Major.NETWORKING
} else {
false
}
}
}
然后在 MainActivity中动态注册广播
class MainActivity : AppCompatActivity() {
private val mBluetoothStateReceiver:BluetoothStateReceiver = BluetoothStateReceiver()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
registerBluetoothReceiver()
}
private fun registerBluetoothReceiver(){
val intentFilter = IntentFilter()
intentFilter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED)
intentFilter.addAction(BluetoothDevice.ACTION_ACL_CONNECTED)
intentFilter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECTED)
intentFilter.addAction("android.bluetooth.BluetoothAdapter.STATE_OFF")
intentFilter.addAction("android.bluetooth.BluetoothAdapter.STATE_ON")
registerReceiver(mBluetoothStateReceiver,intentFilter)
}
}
最后在 AndroidManifest.xml声明权限
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
记得取消注册广播,不然打开其他音乐应用的时候,程序可能会crash
2. 监听蓝牙设备键按下
####################################2022-04-28更新############################
1.疑似Bug,需要在初始化MediaPlayer之后再注册才会生效,MediaButtonReceiver(applicationContext,this)放在MeidePlayer初始化之后代码
2.MediaSession只能有一个实例,如果在程序中创建了多个实例也会导致接收不到,其实看它命名也应该知道了...
####################################2022-04-28更新############################
要监听蓝牙设备的按键按下,你的应用需要处于音乐播放的状态,比如应用正在使用 MediaPlayer播放音频,
如果未处于音频播放状态是不会触发回调方法.所以在演示代码中添加了MediaPlayer来播放音频.
首先新建一个类MediaButtonReceiver类
class MediaButtonReceiver(mContent: Context, mKeyDownListener: IKeyDownListener) {
//创建一个MediaSession的实例,参数2是一个字符串,可以随便填
private val mMediaSession = MediaSession(mContent, javaClass.name)
internal annotation class KeyActions {
companion object {
//好像还支持手柄按键...
//所有keyCode参考:https://www.apiref.com/android-zh/android/view/KeyEvent.html
var PLAY_ACTION: Int = 126
var PAUSE_ACTION: Int = 127
var PREV_ACTION: Int = 88
var NEXT_ACTION: Int = 87
}
}
init {
mMediaSession.setCallback(object : MediaSession.Callback() {
override fun onMediaButtonEvent(mediaButtonIntent: Intent): Boolean {
val keyEvent: KeyEvent =
mediaButtonIntent.getParcelableExtra(Intent.EXTRA_KEY_EVENT)
?: return false
mKeyDownListener.onKeyDown(keyEvent.keyCode)
//返回值的作用跟事件分发的原理是一样的,返回true代表事件被消费,其他应用也就收不到了
return true
}
})
mMediaSession.setFlags(MediaSession.FLAG_HANDLES_MEDIA_BUTTONS or MediaSession.FLAG_HANDLES_TRANSPORT_CONTROLS)
mMediaSession.isActive = true
}
interface IKeyDownListener {
fun onKeyDown(@KeyActions keyAction: Int)
}
}
然后在 MainActivity添加播放的代码
class MainActivity : AppCompatActivity(),MediaButtonReceiver.IKeyDownListener {
private val tag = javaClass.simpleName
private val mMediaPlay:MediaPlayer = MediaPlayer()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
mMediaPlay.reset()
val audioAttributesBuilder = AudioAttributes.Builder().setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
mMediaPlay.setAudioAttributes(audioAttributesBuilder.build())
//注意文件读写权限
mMediaPlay.setDataSource(Environment.getExternalStorageDirectory().toString() + File.separator + "1.ape")
mMediaPlay.setOnPreparedListener{
mMediaPlay.start()
MediaButtonReceiver(applicationContext,this)
}
mMediaPlay.prepareAsync()
}
override fun onKeyDown(keyAction: Int) {
when(keyAction){
MediaButtonReceiver.KeyActions.PLAY_ACTION -> Log.d(tag,"播放...")
MediaButtonReceiver.KeyActions.PAUSE_ACTION -> Log.d(tag,"暂停...")
MediaButtonReceiver.KeyActions.PREV_ACTION -> Log.d(tag,"上一首...")
MediaButtonReceiver.KeyActions.NEXT_ACTION -> Log.d(tag,"下一首...")
}
}
}
打印结果
参考:
Android 扫描蓝牙设备并获取设备类型
ボタンイベントの受信と処理
