Modificato il main.js

reso funzionante lo script, reinstaziando l' oggetto e facendo lo stop
di tutte le tracks 
consiglio di cambiare libreria poichè presenta numerosi bug

things/static/things/main.js

@@ -8,7 +8,8 @@ $(function () {
  return;
  }
  $("input#id_id")[0].value = result;
- $("#qr-scan").modal("hide");
+ $("#qr-scan").modal("toggle");
+ 
  };
 
  $("#cameraProcess").click(function(e) {
@@ -30,16 +31,30 @@ $(function () {
  }
  var video = document.querySelector("video");
  var reset = document.querySelector("#reset");
-
+ var stop = document.querySelector('#stop');
+ 
  // prepare a canvas element that will receive the image to decode, sets
  // the callback for the result and then prepares the videoElement to
  // send its source to the decoder.
- qr.decodeFromCamera(video, resultHandler);
+ qr.decodeFromCamera(video, resultHandler,true);
  // attach some event handlers to reset and stop whenever we want.
  reset.onclick = function () {
- qr.decodeFromCamera(video, resultHandler);
+ for (var i = 0; i < qr.stream.getTracks().length; i++){
+ qr.stream.getTracks()[i].stop();
+ 
+ }
+ qr = new QCodeDecoder(); 
+ qr.decodeFromCamera(video, resultHandler,true);
+ 
+ 
  };
+ 
  }).on("hide.bs.modal", function() {
- qr.stop();
+ for (var i = 0; i < qr.stream.getTracks().length; i++){
+ qr.stream.getTracks()[i].stop();
+ 
+ }
+ qr = new QCodeDecoder(); 
+ 
  });
 });