ios - 在 AVAudioSession 中使用 != buk。 swift 2 中的当前路线

Question

我收到错误 Binary operator '!=' cannot be applied to operands of type '[AVAudioSessionPortDescription]' and 'NilLiteralConvertible in Swift 2，这在 Swift 1 之前很好程序检查耳机线是否插入

var currentRoute = AVAudioSession.sharedInstance().currentRoute 

 if currentRoute.outputs != nil {

                for description in currentRoute.outputs {
                    if description.portType ==

                        AVAudioSessionPortHeadphones {
                        print("headphone plugged in")
                        auximage.image=on

                    } else {
                        print("headphone pulled out")

                        auximage.image=off
                    }
                }
            } else {
                print("requires connection to device")
            }

Answer 1

currentRoute 和 outputs 都是非空的。你可以简单地做

for output in currentRoute.outputs {

仅此而已。