QML Warnings

Veltroniv

**Hello everyone,

I'm currently facing some warnings while compiling my QML application, and I'm not quite sure how to resolve them. Here are the warnings I'm getting:

qml/pages/LoginPage.qml:20:3: QML Connections: Cannot assign to non-existent property "onLoginFailed"
qml/pages/LoginPage.qml:20:3: QML Connections: Cannot assign to non-existent property "onLoginCorrect"
qml/pages/LoginPage.qml:21: ReferenceError: g_apiManager is not defined
qml/pages/LoginPage.qml:22:5 Parameter "token" is not declared. Injection of parameters into signal handlers is deprecated. Use JavaScript functions with formal parameters instead.

Here's the relevant code snippet from LoginPage.qml:

function loginCorrectHandler(token) {
  console.log("Token:", token)
}

Connections {
  target: g_apiManager
  onLoginCorrect: {
    loginCorrectHandler(token)
  }
  onLoginFailed: {
    console.log("Login failed")
  }
}

And here's the corresponding C++ code:

Q_INVOKABLE void loginCorrect(const QString& token);
Q_INVOKABLE void loginFailed();

main.cpp

    ApiManager g_apiManager;
    engine.rootContext()->setContextProperty("g_apiManager", &g_apiManager);

Everything works perfectly fine, but i dont know how to get rid of these warnings.
Could anyone please help me understand how to resolve these warnings?

Thank you in advance for your help!

JoeCFD

@Veltroniv said in QML Warnings:

Q_INVOKABLE void loginCorrect(const QString& token);
Q_INVOKABLE void loginFailed();

these funcs are not signals. your Connections treat them as signals.

Q_INVOKABLE void loginCorrect(const QString& token);
Q_INVOKABLE void loginFailed();

Veltroniv

@JoeCFD
so is any option to remove those warnings? in my cpp.h i declared them as signals.

signals:
   Q_INVOKABLE void loginCorrect(const QString& token);
   Q_INVOKABLE void loginFailed();

or it is what it is ?

JoeCFD

@Veltroniv
ReferenceError: g_apiManager is not defined

show more code about

    ApiManager g_apiManager;
    engine.rootContext()->setContextProperty("g_apiManager", &g_apiManager);

Bob64 is right. If the funcs are signals, Q_INVOKABLE is not needed.

Bob64

@Veltroniv remove Q_INVOKABLE. Marking a function as Q_INVOKABLE makes it callable from QML, so you would expect to use it like this in QML code:

g_apiManager.loginCorrect("token");

Q_INVOKABLE is more like making a function a slot.

Veltroniv

@Bob64, I changed the placement of the engine.rootContext(...) line, moving it after the initialization of engine. Now, I don't get such errors. I placed it before the
felgo.setMainQmlFileName(QStringLiteral("qml/Main.qml"));line, and it works. The warnings disappear.

I'm left with only one warning now:

Parameter "token" is not declared. Injection of parameters into signal handlers is deprecated. Use JavaScript functions with formal parameters instead.

So, I emit the signal from C++ as emit LoginCorrect(token), and I'm trying to catch that in QML by:


  function loginCorrectHandler(token) {
    console.log("Token:", token)
  }

  Connections {
    target: g_apiManager
    onLoginCorrect: {
      loginCorrectHandler(token)
    }
    onLoginFailed: {
      console.log("Login failed")
    }
  }

It's pointing out that I'm using deprecated functions. How should I do it correctly?

//EDIT
That was quite easy, i did it by:

    onLoginCorrect: function (token) {
      console.log("Token:", token)
    }

Correct me if im wrong. Thanks :)

GrecKo

@Veltroniv the preferred Connections syntax is now:

Connections {
    function onLoginCorrect(token) {
        console.log("Token: ", token);
    }
}