Trouble to C++ signal to call a QML slot

Similar Questions

• Connect the signal in the C++ QML?

  Hello

  Sorry in advance for this noobish question

  My QML, I'd like to call C++ function to call the camera and then on the saved photo, I would like to save the url for further processing.

  The invocation and the seizure of the URL does not work correctly.

  The problem is that I can't send a signal of C++ to QML to send the url to QML for further processing.

  Trigger from QML:
  
  Button {
     text: "Snapshot"
     onClicked: {
      app.invokeCamera();
     }
  }
  
  void App::invokeCamera() {
      InvokeRequest request;
      request.setTarget("sys.camera.card");
      request.setAction("bb.action.CAPTURE");
      QByteArray data;
      data.append("full");
      request.setData(getShareRecipeData());
      mInvokeManager->invoke(request);
  }
  
  void App::childCardDone(
          const bb::system::CardDoneMessage &doneMessage) {
      QString url = "";
      qDebug() << "childCardDone reason:" << doneMessage.reason();
      qDebug() << "childCardDone data:" << doneMessage.data();
  
      if (doneMessage.reason().compare("save") == 0) {
          url = "file://" + doneMessage.data();
      } else if (doneMessage.reason().compare("save") == 0) {
          showError(doneMessage.data());
      }
  // This doesn't seem to send to QML
      emit cameraCaptureCompleted(url);
  }
  
  In C++:
  
  signals:
      void cameraCaptureCompleted(const QString &url);
  

  QML to signal received (somehow this must be duplicated?)

  signal cameraCaptureCompleted (string imageLink)
  onCameraCaptureCompleted: {}
  Console.Debug ("link to the image:" + imageLink);

  }

  The onCameraCaptureCompleted never triggered. The console.debug ("link to the image:" + imageLink); did not show anything.

  Thanks for your help!

  OK, I went back and looked at your provided code again and I see you try to put your location of onCameraCaptureCompleted on the Page, which certainly won't work, since the Page is not the class that has the cameraCaptureCompleted signal. I suggest one of these three approaches:

  Page {   id: myPage
     attachedObjects: [
        App {
           id: myApp
           onCameraCaptureCompleted: {
              // ---Do your stuff
           }
        }
     }
  }
  

  ... or if you prefer the Manager to appear on the page do this way:

  Page {
     id: myPage
     attachedObjects: [
        App {
           id: myApp
        }
     }
     function cameraCaptureCompletedHandler( imageLink ) {
        // ---Do your stuff
     }
     onCreationCompleted: {
        myApp.cameraCaptureCompleted.connect(myPage.cameraCaptureCompletedHandler);
     }
  }
  

  If you don't want to mess with connect() you could do the last example that much too:

  Page {
     id: myPage
     attachedObjects: [
        App {
           id: myApp
           onCameraCaptureCompleted: {
              myPage.cameraCaptureCompletedHandler( imageLink );
           }
        }
     }
     function cameraCaptureCompletedHandler( imageLink ) {
        // ---Do your stuff
     }
  }
  

  Of course, all these examples assume that you have successfully exposed the App class to QML with qmlRegisterType(). The signal you want to respond to being on the App class, you must place your location, or connect the App::cameraCaptureCompleted signal to your location explicitly.

  Hope it is clearer to you now.

• Connection of signals (with parameter) in QML.

  Hello

  I want to connect a signal (with parameter) in QML. I have the signal of my PPC and I am able to do that in QML, when I use signals that has no parameters.

  I want to connect to signals which takes the parameter.

  app.mySignal.connect (button.doSomething);

  I do not mySignal() issue, works very well.

  Want to do something like issue mySignal (int) and acess as QML in

  -Thank you

  your signal is:

  mysignal (QString)

  then connect to a function like that (qml)

  myClass.mysignal.connect (onmysignal)

  and:

  function onmysignal (mystring) {}

  Console.log ("my string is:" + mystring)

  }

  If you have several settings, you must be careful with the order and better to use descriptive names, as there is no type in the function definition.

• Stop a signal to connect to the slot machine

  Hello

  Is it possible to stop broadcasting a SIGNAL?

  I had defined a SIGNAL to connect to a SLOT machine at some point earlier.

  But now I want to stop this SIGNAL to connect to the purpose of the LOCATION.

  I tried this thing

  definition of a signal to connect to the slot machine

  connectResult = connect (sensor, SIGNAL (readingChanged ()), this, SLOT (accelerationReadingChanged ()));

  I use to stop

  Connect (sensor, SIGNAL (readingChanged ()), this, SLOT());

  But he does not have to issue.

  use disconnect to disconnect the signal.
  signals and slots allow n connections n a new connection does not overwrite the old connect.

• Connect the signal to the PRC to slot QML

  Hi guys.,.

  Please help me with this

  I'm issuing a custom signal called imageLoaded of CPP that contains an image as a parameter. How can I connect this signal to a slot in QML and can access the image...?

  Thanks in advance...

  For example:

  import bb.cascades 1.0
  
  Page {
      id: myPage
      Container {
          layout: DockLayout {}
          Label {
              id: myLabel
              text: qsTr("Hello World")
              textStyle.base: SystemDefaults.TextStyles.BigText
              verticalAlignment: VerticalAlignment.Center
              horizontalAlignment: HorizontalAlignment.Center
          }
          Button {
              text: "Press me"
              onClicked: {
                  console.log("Boton clicked");
                  cppObject.imageLoaded.connect(onImageLoaded);
                  cppObject.executeCppFunction();
              }
  
          }
      }
  
      function onImageLoaded(message) {
          console.log("enter to slot in qml");
          myLabel.text = message;
      }
  }
  
  --------------------
  
  #ifndef ApplicationUI_HPP_
  #define ApplicationUI_HPP_
  
  #include 
  
  namespace bb { namespace cascades { class Application; }}
  
  class ApplicationUI : public QObject
  {
      Q_OBJECT
  public:
      ApplicationUI(bb::cascades::Application *app);
      virtual ~ApplicationUI() {}
  
      Q_INVOKABLE void executeCppFunction();
  
  signals:
      void imageLoaded(QString message);
  };
  
  #endif 
  
  #include "applicationui.hpp"
  
  #include 
  #include 
  #include 
  
  using namespace bb::cascades;
  
  ApplicationUI::ApplicationUI(bb::cascades::Application *app)
  : QObject(app)
  {
      QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);
  
      QmlDocument::defaultDeclarativeEngine()->rootContext()->setContextProperty("cppObject", this);
  
      AbstractPane *root = qml->createRootObject();
      app->setScene(root);
  
  }
  
  void ApplicationUI::executeCppFunction() {
      emit imageLoaded("Hello from C++ Signal");
  }
  

• No signal after call

  I really want to keep complaining about the update. Especially since I waited for this for a long time. I like a lot of changes. I like the new UI, animations of the lollipop, the new voice of the bike, the new view of the bike with the additional information (except the ' fixing' of the vague bug!) But! A new bug, I've noticed, is that immediately after the end of a call (even after the rejection of an incoming call) the signal disappears for 1-2 seconds. Then he comes back! The reception is very good, where I am currently. It happens after each call, and it's boring! If anyone else noticed that?

  It is a problem of old age (I'm talking about Greece )

  https://forums.Motorola.com/posts/9caa9a2bea

  You have to live with it, no one of Motorola or forums will help... I had this problem since I bought the phone even after that and I got replacement and even after the 5.1 update.

• call a QML file code c ++

  Hello.

  I am newbie to blackberry 10 development...

  actaully I got the credentials to the server and power analyzes the user name and password...

  now I have to redirect to the new file qml by c ++.

  So I will be gratefull if you guide or help me...

  Thanks to anticipate...

  You should find a lot of code when you check out the samples.

  to send a signal of c ++ you define first the signal in the header. Here's an example, let's say this is in app.hpp:

  signals:
      void numberOfItems(int numberOfItems);
      void numberOfItemsError(QString message);
  

  to send the signal in c ++ you write

  emit numberOfItems(5);
  

  to receive the signal in QML, you must register at the first class (this is already done when you create a new application of waterfalls).

  Just to show you, that it would look like this:

  QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);
  qml->setContextProperty("app", this);
  

  Qml, you connect the signal to a qml function, for example onNumberOfItems

  app.numberOfItems.connect(onNumberOfItems)
  

  the function is executed when the signal is emitted:

  function onNumberOfItems(number){
    console.log("number of items: "+number);
  }
  

  That should cover it. It gets a little more complicated when you want to send complex objects with the signal.

• Call C++ qml button Fuctions

  Button * newButton = root->findChild ("eat");
  Connect (newButton, signal(Button::clicked()),this,slot(ont()));)

  You may need to provide a little more information for anyone to determine what the problem is. But try the link below, it has good examples of C++ / QML integration and then ask your question on this basis, with more details

  https://developer.BlackBerry.com/Cascades/documentation/dev/integrating_cpp_qml/index.html

• call in QML Appworld

  Hello good evening brothers, how could invoke in QML Appworld to use an icon in my app with it.

  Here's some code for you

  Page {
              id: tab2
              Button {
                  id: awbutton
                  text: "Click me"
                  attachedObjects: [
                            Invocation {
                                  id: invoke
                                  query: InvokeQuery {
                                  mimeType: "application/x-bb-appworld"
                                  uri: "appworld://content/124432"
                                  }
                          }
    ]
  
              onClicked: {
              invoke.trigger("bb.action.OPEN")
                }
  
          }
  }
  

• call the function slot page of listItem

  -J' have a button inside a ListItemComponent (caritem) Custom and when I click on it I want to call a function of slit of the page that contains the list (carsListPage)

  CODE
  -CustomListItem contains a button that triggers the signal named itemchangePicture

  {Page}
      ID: carsListPage

  {Of container
          
  {To ListView
              ID: carsList
  dataModel: carsModel

  listItemComponents:]
  {ListItemComponent}
                  ID: listItem
  type: 'point '.
  CustomListItem {//contains a signal called itemchangePicture
                         ID: carItem
  onCreationCompleted: {}
                              
             carItem.itemchangePicture.connect (carsListPage.changePicture); This book of doewn can't can not find carsListPage
  }}}

  Slot function to change the photo to carsListPage
    function changePicture() {}
  change the image
  }
           
  } / / Page

  Thank you

  In the ListView docs, read carefully the section from "Visual list in QML", especially the parts on the ListItem.view and the surrounding things.

  Basically, you need to do what you do indirectly through a property on the ListView and access via ListItem.view, or similar approaches.

• Connection signal of C++ with slot QML

  Before ask you, I searched for answers to this question, but I have not found a satisfactory example.

  I have set up a service network in C++ that performs queries to REST against a backend. An example query would be to download a given element, the id of the item.

  Once the item is extracted, I emit a signal such as:

  itemReceived(QString& itemId, QString& item);
  

  My question is how can I wire this signal to the slot in a QML page so that the status of the answer? I tried to connect the signal on the Qml in C++ slot, as follows:

  QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);
  QObject::connect(this->networkingService,
                       SIGNAL(itemReceived(QString&, QString&)),
                       qml, SLOT(onItemReceived(QString&, QString&));
  

  With a correspondent QML "slot" like this:

      function onItemReceived(x, y) {
          console.log("*********************");
          console.log("Item Received!");
          console.log("*********************");
      }
  

  But it does not work. I also tried using the element of connection of the QtQuick lib, but this also fails.

  Any help would be greatly appreciated. Even if he were to propose a better architecture for the "path of the cascades. Thank you!

  In C++:
  QmlDocument * qml = QmlDocument::create("asset:///main.qml").parent(this);
  QML-> setContextProperty ("_app", this);

  In QML:
  {Page}
  onCreationCompleted: {}
  _APP.itemReceived.connect (onItemReceived)
  }

  function onItemReceived (x, y) {}
  Console.log("***");
  Console.log ("point received!");
  Console.log("***");
  }

  // ...
  }

• Can headless part of the application calls a function QML?

  Normally, when you write code in c ++ in the part of the user interface of the code, I am able to call the function of any file QML by writing the code below.

  QmlDocument *qmldoc = QmlDocument::create("asset:///Functions.qml");
  AbstractPane *root = qmldoc->createRootObject();
  QMetaObject::invokeMethod(root, "printResult");
  

  In headless of demand, I create another qml file, called "NotificationHandler.qml" in the current folder of the game without head. In one of the file c ++ without head when I write the same thing, it gives an error indicating that

  C:/bbndk/target_10_3_0_698/qnx6/usr/include/bb/cascades/resources/qmldocument.h:366: undefined reference to `bb::cascades::QmlDocument::QmlDocument(QUrl const&)'
  

  Below, you will find all the code inside the service.cpp which is the game file without the application head.

  #include "service.hpp"
  
  #include 
  #include 
  #include 
  #include 
  #include 
  #include 
  
  #include 
  
  using namespace bb::cascades;
  using namespace bb::platform;
  using namespace bb::system;
  
  Service::Service() :
          QObject(),
          m_notify(new Notification(this)),
          m_invokeManager(new InvokeManager(this))
  {
      m_invokeManager->connect(m_invokeManager, SIGNAL(invoked(const bb::system::InvokeRequest&)),
              this, SLOT(handleInvoke(const bb::system::InvokeRequest&)));
  
      NotificationDefaultApplicationSettings settings;
      settings.setPreview(NotificationPriorityPolicy::Allow);
      settings.apply();
  
      m_notify->setTitle("NotificationWork Service");
      m_notify->setBody("NotificationWork service requires attention");
  
      bb::system::InvokeRequest request;
      request.setTarget("com.example.NotificationWork");
      request.setAction("bb.action.START");
      m_notify->setInvokeRequest(request);
  
      onTimeout();
  }
  
  void Service::handleInvoke(const bb::system::InvokeRequest & request)
  {
      if (request.action().compare("com.example.NotificationWorkService.RESET") == 0) {
          triggerNotification();
      }
  }
  
  void Service::triggerNotification()
  {
      qDebug() << "first";
  
      QmlDocument *qmldoc = QmlDocument::create("asset:///NotificationHandler.qml");
      AbstractPane *root = qmldoc->createRootObject();
      QMetaObject::invokeMethod(root, "startNotificationService");
  
      qDebug() << "second";
      // Timeout is to give time for UI to minimize
      // QTimer::singleShot(2000, this, SLOT(onTimeout()));
  }
  
  void Service::onTimeout()
  {
      Notification::clearEffectsForAll();
      Notification::deleteAllFromInbox();
      m_notify->notify();
  }
  

  I use the same logic, but apparently it is forbidden to treat the QML files in without the request or I have made a serious mistake. Could you please help?

  I thank very you much.

  usually the part without head does not reference libraries of stunts because they have a serious memory footprint.
  The part without being limited in memory head, which gives it its own UI isn't usually a good idea.

• Object to QML C++ signal/slot mechanism transfer

  Hello!

  I have a simple class:

  // myclass.hh
  
  class MyClass : public QObject {
  
      Q_OBJECT
  
      Q_PROPERTY(QString title READ title)
  
  public:
      MyClass(QObject* parent = nullptr)
          : QObject(parent)
      {}
  
      ~MyClass() {}
  
      MyClass(const MyClass&, QObject* parent = nullptr)
          : QObject(parent)
      {}
  
      QString title() const
      {
          return title_;
      }
  
  private:
      QString title_;
  };
  
  Q_DECLARE_METATYPE(MyClass);
  

  and in the main function, I save my metatype system class

  // main.cc
  
  ...
  qRegisterMetaType("MyClass");
  
  MainClass mainclass;qml->setContextProperty("mainclass", mainclass);
  ...
  

  and in another place, I try to convey the purpose of the MyClass class via the signal:

  // mainclass.hhclass MainClass : public QObject {    Q_OBJECT
  ...
  signals:
      void my_signal(MyClass);
  ...
  };
  // mainclass.cc
  ...
      MyClass mc;
      emit my_signal(mc);
  ...
  

  and try to catch this object in qml slot:

  // .qml
  
  Container {
      onCreationCompleted: {
          mainclass.my_signal.connect(signalHandler)
      }
  
      function signalHandler(myClassObj) {
          console.log('we here') // output 'we here'
          console.log(myClassObj.title) // output 'undefined'
          console.log(myClassObj.title()) // empty output
      }
  }
  

  Macro Q_INVOCABLE added before the declaration of MyClass::title() has the same effect.

  What is wrong with my code?

  This is the signal for all

  Q_SIGNALS:
  
      void addedToAllOrder(Order* order);
  

  Order is registered:

  qmlRegisterType("org.ekkescorner.data", 1, 0, "Order");
  

  Import in qml:

  import org.ekkescorner.data 1.0
  

  Qml connection:

  onCreationCompleted: {
          dataManager.addedToAllOrder.connect(onAddedToAllOrder)
      }
  

  Important! set a property in qml:

  Page {
      id: orderPage
      .....
      property Order anotherOrder
  

  then everything works well in qml function (SLOT)

      function onAddedToAllOrder(theOrder) {
          anotherOrder = theOrder
          console.debug("Order added: " + anotherOrder.nr)
      }
  

  This is how I have face this kind of stuff

  using a pointer ensures that there'e really a single object used in memory and you can use QML.

  the cool thing: he is glad assist in qml: type anotherOrder. ... gives all properties to select and you deal directly with your C++ object. don't forget that your C++ class is the owner (parent) of your object

  hope that gives you some ideas to try

• Error while establishing an Http connection. Once finished signal request is displayed, no call slot

  I'm instantiated MyNetwork class on click of a button in my app class.

  Therefore it is called class constructor MyNetwork in which I'm checking the availability of the network.

  Once found an available network, a sendRequest() method is called that a get request is initialized.

  And the QNetworkAccessManager object emits a finished(QNetworkReply *) signal is connected to a slot (requestFinished(QNetworkReply *reply)) of this class of MyNetwork .

  When the user clicks on the button in the file app.cpp, create an object of class MyNetwork and checking the availability of the network works within its constructor.

  also the connect() method returns true , but sinking ever crack (requestFinished(QNetworkReply *reply)) method where I am Manager of my answer.

  MyNetwork. HPP

   

   

  #ifndef MYNETWORK_HPP_
  #define MYNETWORK_HPP_
  
  #include
  #include 
  #include
  #include
  #include
  #include 
  #include 
  #include
  
  /*!
   * @brief Network Connection Implementation
   */
  class MyNetwork:public QObject
  {
      Q_OBJECT;
  
      public :
          MyNetwork();
  
          /*!
           * @brief Method to create and send request
           */
          void sendRequest();
          /*!
           * @brief Method to check if network is available
           */
          bool isNetworkAvailable();
  
      private slots:
              void requestFinished(QNetworkReply *reply);
  
  };
  
  #endif /* MYNETWORK_HPP_ */
  

  MyNetwork.cpp

   

   

  
  

  #include
  #include
  #include
  #include
  
  QNetworkAccessManager *mNetworkMgr;
  
  MyNetwork::MyNetwork() {
  
      if (isNetworkAvailable()) {
          sendRequest();
      } 
  
  }
  
  void MyNetwork::sendRequest() {
  
      mNetworkMgr = new QNetworkAccessManager(this);
      QNetworkReply *reply =
              mNetworkMgr->get(
                      QNetworkRequest(
                              QUrl(
                                      "http://developer.blackberry.com/cascades/files/documentation/device_platform/networking/model.xml")));
      if (reply) {
          qDebug() << "Reply from server is " << reply;
      }
      bool resFromServer = connect(mNetworkMgr, SIGNAL(finished(QNetworkReply*)),
              this, SLOT(requestFinished(QNetworkReply*)));
      qDebug() << "Connection is success : ? : " << resFromServer;
      Q_ASSERT(resFromServer);
      Q_UNUSED(resFromServer);
  }
  
  void MyNetwork::requestFinished(QNetworkReply *reply) {    if (reply) {
          if (reply->error() == QNetworkReply::NoError) {
              qDebug() << "No Error";
          } else {
              int httpStatus = reply->attribute(
                      QNetworkRequest::HttpStatusCodeAttribute).toInt();
              qDebug() << "Error and the code is " << httpStatus;
          }
          reply->deleteLater();
      } else {
          qDebug() << "Reply comes out to be null";
      }
  }
  
  bool MyNetwork::isNetworkAvailable() {
      QNetworkConfigurationManager netMgr;
      QList mNetList = netMgr.allConfigurations(
              QNetworkConfiguration::Active);
      if (mNetList.count() > 0) {
          if (netMgr.isOnline()) {
              return true;
          } else {
              return false;
          }
      } else {
          return false;
      }
  }
  

  Hmm. I just did a quick test for the for you network code.

  I movedbool resFromServer = connect(mNetworkMgr, SIGNAL(finished(QNetworkReply*)),
  this, SLOT(requestFinished(QNetworkReply*)));
  
  to  be before
  
  QNetworkReply *reply =
  mNetworkMgr->get(
  QNetworkRequest(
  QUrl(
  "http://developer.blackberry.com/cascades/files/documentation/device_platform/networking/model.xml")));
  
  in my test.
  

  As I mentioned to signal before start us sending application network.

  I got "Error no." in the newspaper which seemed to have indicated that the signal/slot was triggerred properly in my case.

  Question for you:

  How did you create your object "MyNetwork"?

  is the object still alive when the network request signal is triggerred?

  Maybe the code for create/destorying your object "MyNetwork" segment will be useful

• QML does not recognize the custom parameters of the signal object.

  Here is my sample code to test by passing an object custom c ++ qml.

  My custom object:

  class TestObject {}

  public:

  QString testString;

  TestObject() {testString = 'Hello' ;}

  };

  ...

  signals:

  void testErreur (TestObject * testObject);

  I declare it and send the singal of c ++

  Q_DECLARE_METATYPE (TestObject);

  ...

  qRegisterMetaType('TestObject');

  ...

  issue of testError (newTestObject ());

  and expect to receive the onTestError with the testObject setting

  He compiled and can receive the onTestError in qml slot, but it generates an error running this

  QMetaProperty::read: Unable to handle the kind of data not saved ' TestObject * "property"QDeclarativeBoundSignalParameters::testObject ".

  Asset:///testSreen.QML:123: error: unknown method parameter type: TestObject *.

  I did a couple of hours of looking on the forum but found no solution.  Hope that developers who have experience on the similar question can help out.

  Thank you

  Tyler

  Thanks Andrey,

  I changed it to Q_DECLARE_METATYPE(TestObject *); but still have the same error.

  The code that I showed is in fact to reduce the problem.  The actual design is to have a c ++ based customControl in the qml and I plan receive the signal and proceed the testObject to my c ++ customControl and release it there.