Fix Issue #22

ios/Classes/SwiftDtmfPlugin.swift

@@ -4,24 +4,36 @@ import AVFoundation
 import CallKit
 
 public class SwiftDtmfPlugin: NSObject, FlutterPlugin {
-
+    
     var _engine: AVAudioEngine
     var _player:AVAudioPlayerNode
     var _mixer: AVAudioMixerNode
+    var _playCount = 0
 
-  public override init() {
-    _engine = AVAudioEngine();
-    _player = AVAudioPlayerNode()
-    _mixer = _engine.mainMixerNode;
+    public override init() {
+        _engine = AVAudioEngine();
+        _player = AVAudioPlayerNode()
+        _mixer = _engine.mainMixerNode;
+
+        super.init()
+
+        NotificationCenter.default.addObserver(self, selector: #selector(handleRouteChange), name: AVAudioSession.routeChangeNotification, object: nil)
+    }
 
-    super.init()
+    public static func register(with registrar: FlutterPluginRegistrar) {
+        let channel = FlutterMethodChannel(name: "flutter_dtmf", binaryMessenger: registrar.messenger())
+        let instance = SwiftDtmfPlugin()
+        registrar.addMethodCallDelegate(instance, channel: channel)
     }
 
-  public static func register(with registrar: FlutterPluginRegistrar) {
-    let channel = FlutterMethodChannel(name: "flutter_dtmf", binaryMessenger: registrar.messenger())
-    let instance = SwiftDtmfPlugin()
-    registrar.addMethodCallDelegate(instance, channel: channel)
-  }
+    @objc func handleRouteChange(notification: Notification){
+      _player.stop()
+      if(_engine.isRunning){_engine.disconnectNodeOutput(_player)}
+      _engine.stop()
+      _engine = AVAudioEngine();
+      _player = AVAudioPlayerNode()
+      _mixer = _engine.mainMixerNode;
+    }
 
     public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
         let arguments = call.arguments as? NSDictionary
@@ -33,14 +45,14 @@ public class SwiftDtmfPlugin: NSObject, FlutterPlugin {
             let volume =  arguments?["volume"] as? Double
             playTone(digits: digits, volume: volume, samplingRate: samplingRate, durationMs: durationMs, flutterResult: result)
         }
-
+        
     }
 
     func playTone(digits: String, volume: Double?, samplingRate: Double, durationMs: Int, flutterResult: @escaping FlutterResult)
     {
-
+        
         let _sampleRate = Float(samplingRate)
-
+        
         if let tones = DTMF.tonesForString(digits) {
             let audioFormat = AVAudioFormat(commonFormat: .pcmFormatFloat32, sampleRate: Double(_sampleRate), channels: 2, interleaved: false)!
 
@@ -69,15 +81,39 @@ public class SwiftDtmfPlugin: NSObject, FlutterPlugin {
             } catch let error as NSError {
                 flutterResult(false)
                 print("Engine start failed - \(error)")
+                return
             }
 
-            _player.scheduleBuffer(buffer, at:nil,completionHandler:nil)
+            _player.scheduleBuffer(buffer, at:nil,completionCallbackType: .dataPlayedBack){  [weak self] _ in
+                Task{ @MainActor in
+                    self?.stopTone()
+                }
+            }
             if (volume != nil) {
                 _player.volume = Float(volume!)
             }
             _player.play()
+            _playCount += 1
             flutterResult(true)
+        }
+    }
+
+    private func stopTone(){
+        _playCount -= 1
+        if _playCount > 0 {
+            return
+        }
+
+        _player.stop()
+        if _engine.isRunning {
+            _engine.stop()
+        }
+        do{
+            let session = AVAudioSession.sharedInstance()
+            try session.setCategory(.ambient, mode: .default, options: [])
+            try session.setActive(false, options: [.notifyOthersOnDeactivation])
+        }catch{
+            print("Deactivate failed - \(error)")
+        }
     }
-  }
-
 }

lib/dtmf.dart

@@ -15,19 +15,19 @@ class Dtmf {
   ///
   static Future<bool?> playTone(
       {required String digits,
-      int durationMs =160,
-      double samplingRate =500,
+      int durationMs = 160,
+      double samplingRate = 4000,
       double volume = 1,
-      bool ignoreDtmfSystemSettings=false,
-      bool forceMaxVolume=false}) async {
-
+      bool ignoreDtmfSystemSettings = false,
+      bool forceMaxVolume = false}) async {
     final Map<String, Object?> args = <String, dynamic>{
       "digits": digits,
       "samplingRate": samplingRate,
       "durationMs": durationMs,
       "volume": volume,
-      "ignoreDtmfSystemSettings":ignoreDtmfSystemSettings,
-      "forceMaxVolume":forceMaxVolume};
+      "ignoreDtmfSystemSettings": ignoreDtmfSystemSettings,
+      "forceMaxVolume": forceMaxVolume
+    };
     return await _channel.invokeMethod('playTone', args);
   }
 }