Not able to handle Signals

Praveen.Illa

Hello all,
I am newbie to Qt and trying to load different pages with loader. But, am getting following errors while running

qrc:/ScreenPage.qml:10:5: QML Connections: Detected function "onSampleButtonPressed" in Connections element. This is probably intended to be a signal handler but no signal of the target matches the name.

qrc:/HomeScreen.qml:28: TypeError: Property 'sampleButtonPressed' of object [object Object] is not a function

I think, i am handling the signals and its handlers properly. But, dont know where am doing wrong

My code looks like this
main.qml
Window {
width: 640
height: 480
visible: true
title: qsTr("Hello World")
id: rootWindowID

ScreenPage {
    id:applicationWrapper
    anchors.centerIn: parent
}

}

ScreenPage.qml
Item {
id:screenpage
width: 640
height: 480

Connections {
    target: ScreenConfiguration

    function onSampleButtonPressed(pressed) {
        if(pressed === ScreenConfiguration.Pagenumbers.Page1)
        {
            //pageLoader.source = page1Component
            console.log("Page1")
        }
        else if(pressed === ScreenConfiguration.Pagenumbers.Page2)
        {
            //pageLoader.source = page2Component
            console.log("Page2")
        }
    }
}

/*Home Screen Component*/
Component{
   id:homeScreenComponent

   //QML filenames should always start with Capital letters
    HomeScreen{  }
}

Loader{
    id:pageLoader
    anchors.fill: screenpage
    sourceComponent: homeScreenComponent // default and start page
}

}

HomeScreen.qml
Item {
id: homescreenId
width: 640
height: 480

Text {
    id: txtid1
    text: qsTr("Home Screen")
    width: parent.width
    height: 50
    anchors.left: parent.left
    font.pixelSize: 20
}

Button {
    id: buttonId1
    text: "Button1"
    width: 100
    height: 50
    anchors.top: txtid1.bottom

    onClicked: {
        console.log("Button1 Clicked")
        ScreenConfiguration.sampleButtonPressed(ScreenConfiguration.Pagenumbers.Page1)
    }
}

Button {
    id: buttonId2
    text: "Button2"
    width: 100
    height: 50
    anchors.top: txtid1.bottom
    anchors.left: buttonId1.right

    onClicked: {
        console.log("Button2 Clicked")
        ScreenConfiguration.sampleButtonPressed(ScreenConfiguration.Pagenumbers.Page2)
    }
}

}

ScreenConfiguration.qml
QtObject {

signal sampleButtonPressed(int pressed)

enum Pagenumbers {
    None = 0,
    Page1,
    Page2
}

}

ODБOï

@Praveen-Illa said in Not able to handle Signals:

qrc:/ScreenPage.qml:10:5: QML Connections: Detected function "onSampleButtonPressed" in Connections element. This is probably intended to be a signal handler but no signal of the target matches the name.

that is because of this

Connections {
    target: ScreenConfiguration  //<<  target should be an object

example :

ScreenConfiguration { id: myConfig} // create an object 
Connections {
    target: myConfig

then HomeScreen.qml:28: TypeError: Property 'sampleButtonPressed' of object [object Object] is not a function
same thing; you need an instance/object to access the signals/attributes

onClicked: {
            ScreenConfiguration.sampleButtonPressed(ScreenConfiguration.Pagenumbers.Page1)

since you use ScreenConfiguration in several qml components you would have to create ScreenConfigurationobjects multiple times..
I would move the signal somewhere else and make ScreenConfiguration.qml singleton

Praveen.Illa

@LeLev
Thanks for your quick response, it works