Swift中的CoreMIDI回调

概述我使用以下代码在 Swift Playground中接收MIDI事件： import Cocoaimport CoreMIDIimport XCPlaygroundXCPSetExecutionShouldContinueIndefinitely(continueIndefinitely: true)func notifyCallback(message:UnsafePointer<M 我使用以下代码在 Swift Playground中接收MIDI事件：

import Cocoaimport CoreMIDIimport XCPlaygroundXcpsetExecutionShouldContinueIndefinitely(continueIndefinitely: true)func notifyCallback(message:UnsafePointer<MIDINotification>,refCon:UnsafeMutablePointer<VoID>){    println("MIDI Notify")}func eventCallback(pktList:UnsafePointer<MIDIPacketList>,refCon:UnsafeMutablePointer<VoID>,connRefCon:UnsafeMutablePointer<VoID>){    println("MIDI Read")}var clIEnt = MIDIClIEntRef()MIDIClIEntCreate("Core MIDI Callback Demo" as Nsstring,MIDINotifyProc(copaquePointer([notifyCallback])),nil,&clIEnt)var inPort = MIDIPortRef()MIDIinputPortCreate(clIEnt,"input port",MIDIReadProc(copaquePointer([eventCallback])),&inPort)let sourceCount = MIDIGetNumberOfSources()for var count:UInt = 0; count < sourceCount; ++count{    let src:MIDIEndpointRef = MIDIGetSource(count)    MIDIPortConnectSource(inPort,src,nil)}

我通过将工作的Objective-C代码转换成我认为正确的Swift版本来实现这一点.

它编译并运行正常,直到其中一个回调触发,例如当我拔下MIDI设备或按下其中一个键时.我总是得到一个BAD_EXEC.

任何想法如何使这项工作或Swift只是没有准备好作为网络上的一些博客文章.苹果官方的任何我忽视的事情都清楚地表明Swift尚未准备好进行CoreMIDI回调？

更新2015-03-10：相应的Objective-C代码可在http://www.digital-aud.io/blog/2015/03/10/on-coremidi-callbacks/找到

解决方法 与早期版本相比,Swift3似乎对CoreMIDI有更好的支持.下面显示的示例游乐场演示显示了一些有效的基本CoreMIDI调用.

import Cocoaimport CoreMIDIimport PlaygroundSupport// helper method to extract the display name from a MIdiobjectReffunc midiobjectdisplayname(_ obj: MIdiobjectRef) -> String {    var param: Unmanaged<CFString>?    var capturedname = "Error"    let err = MIdiobjectGetStringProperty(obj,kMIDIPropertydisplayname,&param)    if err == Osstatus(noErr) {      capturedname = param!.takeRetainedValue() as String    }    return capturedname}// method to collect display names of available MIDI destinationsfunc mIDIDestinationnames() -> [String] {    var names:[String] = []    let count:Int = MIDIGetNumberOfDestinations()    for i in 0..<count {        let endpoint:MIDIEndpointRef = MIDIGetDestination(i)        if  endpoint != 0 {            names.append(midiobjectdisplayname(endpoint))        }    }    return names}let destinationnames = mIDIDestinationnames()// check if we have any available MIDI destinations.if destinationnames.count > 0 {    // establish a MIDI clIEnt and output port,and send a note on/off pair.    var mIDiClIEnt:MIDIClIEntRef = 0    var outPort:MIDIPortRef = 0    MIDIClIEntCreate("Swift3 Test ClIEnt" as CFString,&mIDiClIEnt)    MIdioutputPortCreate(mIDiClIEnt,"Swift3 Test OutPort" as CFString,&outPort)    let destNum = 0    let destname = destinationnames[destNum]    var dest:MIDIEndpointRef = MIDIGetDestination(destNum)    var mIDiPacket:MIDIPacket = MIDIPacket()    mIDiPacket.timeStamp = 0    mIDiPacket.length = 3    mIDiPacket.data.0 = 0x90 + 0 // Note On event channel 1    mIDiPacket.data.1 = 0x3D // Note Db    mIDiPacket.data.2 = 100 // VeLocity    var packetList:MIDIPacketList = MIDIPacketList(numPackets: 1,packet: mIDiPacket)    print("Sending note on to \(destname)")    MIdisend(outPort,dest,&packetList)    mIDiPacket.data.0 = 0x80 + 0 // Note off event channel 1    mIDiPacket.data.2 = 0 // VeLocity    sleep(1)    packetList = MIDIPacketList(numPackets: 1,packet: mIDiPacket)    MIdisend(outPort,&packetList)    print("Note off sent to \(destname)")}

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