列出可用的输出音频目标AVAudioSession

Question

我需要列出可用于iOS应用程序的音频输出。我的问题是类似这样的：How to list available audio output route on iOS

我想这代码：

NSError *setCategoryError = nil; 
BOOL success = [[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayback 
                 error: &setCategoryError]; 

NSError *activationError = nil; 
[[AVAudioSession sharedInstance] setActive: YES error: &activationError]; 

… 
NSLog(@"session.currentRoute.outputs count %d", [[[[AVAudioSession sharedInstance] currentRoute] outputs ] count]); 
for (AVAudioSessionPortDescription *portDesc in [[[AVAudioSession sharedInstance] currentRoute] outputs ]) { 
    NSLog(@"-----"); 
    NSLog(@"portDesc UID %@", portDesc.UID); 
    NSLog(@"portDesc portName %@", portDesc.portName); 
    NSLog(@"portDesc portType %@", portDesc.portType); 
    NSLog(@"portDesc channels %@", portDesc.channels); 
} 

但是我始终看到的只是一个输出端口（计数为1），另外，如果我有两个（一个的Airplay和内置扬声器）。 如果我使用音乐应用程序，我可以看到两个端口并在它们之间切换。 在我的应用程序中，我只看到我选择的那个。

还有什么我需要做的？

谢谢

编辑：

我想这段代码，也：

CFDictionaryRef asCFType = nil; 
UInt32 dataSize = sizeof(asCFType); 
AudioSessionGetProperty(kAudioSessionProperty_AudioRouteDescription, &dataSize, &asCFType); 
NSDictionary *audioRoutesDesc = (__bridge NSDictionary *)asCFType; 
NSLog(@"audioRoutesDesc %@", audioRoutesDesc); 

但字典列表只是一个输出目的地。此外，该输入源阵列是空的（我有一个iPhone 4S）

EDIT2：

我得到的东西用MPVolumeView工作。该组件有一个按钮，可让您选择输出音频路由，如在音乐应用程序中。

如果你愿意，你可以隐藏滑块（和只有按钮）使用：

self.myMPVolumeView.showsVolumeSlider = NO; 

Answer 1

尝试这样的事情，它比你更需要，但你可以削减下来：

+ (NSString *) demonstrateInputSelection 
{ 
    NSError* theError = nil; 
    BOOL result = YES; 
    NSMutableString *info = [[NSMutableString alloc] init]; 
    [info appendString: @"  Device Audio Input Hardware\n"]; 

    NSString *str = nil; 
    if(iOSMajorVersion < 7){ 
     str = @"No input device information available"; 
     NSLog(@"%@",str); 
     [info appendFormat:@"%@\n",str]; 

     return info; 
    } 

    AVAudioSession* myAudioSession = [AVAudioSession sharedInstance]; 

    result = [myAudioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:&theError]; 
    if (!result) 
    { 
     NSLog(@"setCategory failed"); 
    } 

    result = [myAudioSession setActive:YES error:&theError]; 
    if (!result) 
    { 
     NSLog(@"setActive failed"); 
    } 

    // Get the set of available inputs. If there are no audio accessories attached, there will be 
    // only one available input -- the built in microphone. 
    NSArray* inputs = [myAudioSession availableInputs]; 
    str = [NSString stringWithFormat:@"\n--- Ports available on %@: %d ---", [UIDevice currentDevice].name , [inputs count]]; 
    NSLog(@"%@",str); 
    [info appendFormat:@"%@\n",str]; 

    // Locate the Port corresponding to the built-in microphone. 
    AVAudioSessionPortDescription* builtInMicPort = nil; 
    AVAudioSessionDataSourceDescription* frontDataSource = nil; 

    for (AVAudioSessionPortDescription* port in inputs) 
    { 
     // Print out a description of the data sources for the built-in microphone 
     str = @"\n**********"; 
     NSLog(@"%@",str); 
     [info appendFormat:@"%@\n",str]; 
     str = [NSString stringWithFormat:@"Port :\"%@\": UID:%@", port.portName, port.UID ]; 
     NSLog(@"%@",str); 
     [info appendFormat:@"%@\n",str]; 
     if([port.dataSources count]){ 
      str = [NSString stringWithFormat:@"Port has %d data sources",(unsigned)[port.dataSources count] ]; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 
     } 

     str = [NSString stringWithFormat:@">%@", port.dataSources]; 
     NSLog(@"%@",str); 
    //  [info appendFormat:@"%@\n",str]; 

     if([port.portType isEqualToString:AVAudioSessionPortLineIn]){ 
      str = @"Line Input found"; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 
     } 
     else if([port.portType isEqualToString:AVAudioSessionPortUSBAudio]){ 
      str = @"USB Audio found"; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 
     } 
     else if ([port.portType isEqualToString:AVAudioSessionPortBuiltInMic]){ 
      builtInMicPort = port; 
      str = @"Built-in Mic found"; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 
     } 
     else if ([port.portType isEqualToString:AVAudioSessionPortHeadsetMic]){ 
      builtInMicPort = port; 
      str = @"Headset Mic found"; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 
     } 
     else{ 
      str = @"Other input source found"; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 
     } 

     // loop over the built-in mic's data sources and attempt to locate the front microphone 
     for (AVAudioSessionDataSourceDescription* source in port.dataSources) 
     { 
      str = [NSString stringWithFormat:@"\nName:%@ (%d) \nPolar:%@ \nType:%@ \nPatterns:%@", source.dataSourceName, [source.dataSourceID intValue], source.selectedPolarPattern, port.portType, source.supportedPolarPatterns]; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 

      //   if ([source.orientation isEqual:AVAudioSessionOrientationFront]) 
      //   { 
      //    frontDataSource = source; 
      //    break; 
      //   } 
     } // end data source iteration 

    } 

    str = @"\n---- Current Selected Ports ----\n"; 
    NSLog(@"%@",str); 
    [info appendFormat:@"%@",str]; 

    NSArray *currentInputs = myAudioSession.currentRoute.inputs; 
// str = [NSString stringWithFormat:@"\n%d current input ports", [currentInputs count]]; 
// NSLog(@"%@",str); 
// [info appendFormat:@"%@\n",str]; 
    for(AVAudioSessionPortDescription *port in currentInputs){ 
     str = [NSString stringWithFormat:@"\nInput Port :\"%@\":", port.portName ]; 
     NSLog(@"%@",str); 
     [info appendFormat:@"%@\n",str]; 
     if([port.dataSources count]){ 
      str = [NSString stringWithFormat:@"Port has %d data sources",(unsigned)[port.dataSources count] ]; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 

      str = [NSString stringWithFormat:@"Selected data source:%@", port.selectedDataSource.dataSourceName]; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 

      if([port.selectedDataSource.supportedPolarPatterns count] > 0){ 
       str = [NSString stringWithFormat:@"Selected polar pattern:%@", port.selectedDataSource.selectedPolarPattern]; 
       NSLog(@"%@",str); 
       [info appendFormat:@"%@\n",str]; 
      } 
     } 
    } 

    NSArray *currentOutputs = myAudioSession.currentRoute.outputs; 
// str = [NSString stringWithFormat:@"\n%d current output ports", [currentOutputs count]]; 
// NSLog(@"%@",str); 
// [info appendFormat:@"%@\n",str]; 
    for(AVAudioSessionPortDescription *port in currentOutputs){ 
     str = [NSString stringWithFormat:@"\nOutput Port :\"%@\":", port.portName ]; 
     NSLog(@"%@",str); 
     [info appendFormat:@"%@\n",str]; 
     if([port.dataSources count]){ 
      str = [NSString stringWithFormat:@"Port has %d data sources",(unsigned)[port.dataSources count] ]; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 

      str = [NSString stringWithFormat:@"Selected data source:%@", port.selectedDataSource.dataSourceName]; 
      NSLog(@"%@",str); 
      [info appendFormat:@"%@\n",str]; 
     } 

    } 

// str = [NSString stringWithFormat:@"\Current Route: %@ Source:%@\n", myAudioSession.currentRoute.portName, myAudioSession.preferredInput.selectedDataSource.dataSourceName]; 
// NSLog(@"%@",str); 
// [info appendFormat:@"%@\n",str]; 


    if(myAudioSession.preferredInput.portName){ 
     str = [NSString stringWithFormat:@"\nPreferred Port: %@ Source:%@\n", myAudioSession.preferredInput.portName, myAudioSession.preferredInput.selectedDataSource.dataSourceName]; 
    } else { 
     str = @"\nNo Preferred Port set"; 
    } 
    NSLog(@"%@",str); 
    [info appendFormat:@"%@\n",str]; 

    return info; 

    if (frontDataSource) 
    { 
     NSLog(@"Currently selected source is \"%@\" for port \"%@\"", builtInMicPort.selectedDataSource.dataSourceName, builtInMicPort.portName); 
     NSLog(@"Attempting to select source \"%@\" on port \"%@\"", frontDataSource, builtInMicPort.portName); 

     // Set a preference for the front data source. 
     theError = nil; 
     result = [builtInMicPort setPreferredDataSource:frontDataSource error:&theError]; 
     if (!result) 
     { 
      // an error occurred. Handle it! 
      NSLog(@"setPreferredDataSource failed"); 
     } 
    } 

    // Make sure the built-in mic is selected for input. This will be a no-op if the built-in mic is 
    // already the current input Port. 
    theError = nil; 
    result = [myAudioSession setPreferredInput:builtInMicPort error:&theError]; 
    if (!result) 
    { 
     // an error occurred. Handle it! 
     NSLog(@"setPreferredInput failed"); 
    } 

    return info; 
} 

Answer 2

AVAudioSessionRouteDescription *currentRoute = [[AVAudioSession sharedInstance] currentRoute]; 
    for (AVAudioSessionPortDescription *output in currentRoute.outputs) { 

    } 

Answer 3

这取决于您的AVAudioSession类别。

您可以安全地假设在iPhone上至少有一个麦克风作为输入，扬声器作为输出。如果你想获得蓝牙/ AirPlay的输出列表，首先你必须确保你的会话类是他们报告给你：

do 
{ 
    try audioSession.setCategory(AVAudioSessionCategoryPlayAndRecord, withOptions: .AllowBluetooth) 
    try audioSession.setActive(true) 
} 
catch let e 
{ 
    debugPrint("failed to initialize audio session: \(e)") 
} 

然后，非直观的方式来获取可用输出是检查AVAudioSession.availableInputs通常是一个蓝牙HFP设备也会有一个麦克风..我现在可能会假设很多..但这是持续获得可用输出的唯一方法。

一个更好的办法是使用MultipleRoute类别，这将给你在访问AVAudioSessionPort