I am working on a project which can play music via HFP device. But here's a problem that I want to detect whether an HFP or A2DP is connected when music is playing.
Now I am using the AVFoundation framework to do this. Here's the code:
- (BOOL)isConnectedToBluetoothPeripheral
{
BOOL isMatch = NO;
NSString* categoryString = [AVAudioSession sharedInstance].category;
AVAudioSessionCategoryOptions categoryOptions = [AVAudioSession sharedInstance].categoryOptions;
if ((![categoryString isEqualToString:AVAudioSessionCategoryPlayAndRecord] &&
![categoryString isEqualToString:AVAudioSessionCategoryRecord]) ||
categoryOptions != AVAudioSessionCategoryOptionAllowBluetooth)
{
NSError * error = nil;
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord
withOptions:AVAudioSessionCategoryOptionAllowBluetooth
error:&error];
if (error) {
[[AVAudioSession sharedInstance] setCategory:categoryString
withOptions:categoryOptions
error:&error];
return isMatch;
}
}
NSArray * availableInputs = [AVAudioSession sharedInstance].availableInputs;
for (AVAudioSessionPortDescription *desc in availableInputs)
{
if ([[desc portType] isEqualToString:AVAudioSessionPortBluetoothA2DP] || [[desc portType] isEqualToString:AVAudioSessionPortBluetoothHFP])
{
isMatch = YES;
break;
}
}
if (!isMatch)
{
NSArray * outputs = [[[AVAudioSession sharedInstance] currentRoute] outputs];
for (AVAudioSessionPortDescription * desc in outputs)
{
if ([[desc portType] isEqualToString:AVAudioSessionPortBluetoothA2DP] || [[desc portType] isEqualToString:AVAudioSessionPortBluetoothHFP])
{
isMatch = YES;
break;
}
}
}
NSError * error = nil;
[[AVAudioSession sharedInstance] setCategory:categoryString
withOptions:categoryOptions
error:&error];
return isMatch;
}
It works well but cause another problem: when music is playing, using this method to detect HFP connection will make music playing interrupt for about two seconds.
So I tried another way which can reduce the effect of detecting HFP connecting. I am using a flag
static BOOL isHFPConnectedFlag
To indicate whether HFP or A2DP is connected. I use previous method to detect the connection only once (when the app is launching) and save the result into isHFPConnectedFlag. What's more, I observe the AudioSessionRouteChange to sync the connection status:
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleAudioSessionRouteChangeWithState:) name:AVAudioSessionRouteChangeNotification object:nil];
When the route change reason is AVAudioSessionRouteChangeReasonNewDeviceAvailable
or AVAudioSessionRouteChangeReasonOldDeviceUnavailable
I can know HFP is connected or disconnected. Unfortunately, when I connect some HFP in my iPhone, the system will not post this notification, so I cannot detect the connection in this situation.
Does anyone know the reason or a better way to implements this (Detecting HFP connection without music playing interrupting)?
Swift 5 version: