AVAudioPlayerNodeを使って音楽の再生、一時停止、再生速度変更、ピッチ変更、ボリューム変更を行う
AVAudioPlayerNodeを使って音楽の再生、一時停止、再生速度変更、ピッチ変更、ボリューム変更を行う方法です。 AVAudioPlayerNodeはAVAudioPlayerではできないようなことができます。 たとえばピッチの変更などAVAudioPlayerでは実現することはできないので、AVAudioPlayerNodeを使う必要があります。
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| import SwiftUI | |
| import AVFoundation | |
| struct ContentView: View { | |
| @State var audioPlayerNode = AVAudioPlayerNode() | |
| @State var audioEngine = AVAudioEngine() | |
| @State var speedControl = AVAudioUnitVarispeed() | |
| @State var pitchControl = AVAudioUnitTimePitch() | |
| @State var isPause = false | |
| var body: some View { | |
| VStack { | |
| HStack { | |
| Button("Start") { | |
| guard let url = Bundle.main.url(forResource: "autumn-leaves", withExtension: "mp3") else { return } | |
| guard let file = try? AVAudioFile(forReading: url) else { return } | |
| audioPlayerNode = AVAudioPlayerNode() | |
| audioEngine.attach(audioPlayerNode) | |
| audioEngine.attach(pitchControl) | |
| audioEngine.attach(speedControl) | |
| audioEngine.connect(audioPlayerNode, to: speedControl, format: nil) | |
| audioEngine.connect(speedControl, to: pitchControl, format: nil) | |
| audioEngine.connect(pitchControl, to: audioEngine.mainMixerNode, format: nil) | |
| audioPlayerNode.scheduleFile(file, at: nil) | |
| try? audioEngine.start() | |
| audioPlayerNode.play() | |
| }.padding() | |
| Button("Pause") { | |
| if isPause { | |
| audioPlayerNode.play() | |
| } else { | |
| audioPlayerNode.pause() | |
| } | |
| isPause.toggle() | |
| }.padding() | |
| Button("Stop") { | |
| audioPlayerNode.volume = 0 | |
| }.padding() | |
| } | |
| HStack { | |
| Button("Rate↑") { | |
| pitchControl.rate += 0.1 | |
| }.padding() | |
| Button("Rate↓") { | |
| pitchControl.rate -= 0.1 | |
| }.padding() | |
| } | |
| HStack { | |
| Button("Pitch↑") { | |
| pitchControl.pitch += 50 | |
| }.padding() | |
| Button("Pitch↓") { | |
| pitchControl.pitch -= 50 | |
| }.padding() | |
| } | |
| HStack { | |
| Button("Rate&Pitch↑") { | |
| speedControl.rate += 0.1 | |
| }.padding() | |
| Button("Rate&Pitch↓") { | |
| speedControl.rate -= 0.1 | |
| }.padding() | |
| } | |
| HStack { | |
| Button("Volume↑") { | |
| audioPlayerNode.volume += 0.2 | |
| }.padding() | |
| Button("Volume↓") { | |
| audioPlayerNode.volume -= 0.2 | |
| }.padding() | |
| } | |
| } | |
| } | |
| } | |
| struct ContentView_Previews: PreviewProvider { | |
| static var previews: some View { | |
| ContentView() | |
| } | |
| } |