如何从QML组件调用自定义信号？

Question

Is there a way to call a signal from a mouseArea included in a component which is loaded somewhere else?

onClicked in the example below is not entered when i click on the rectangle.

The structure needs to remain as defined. To be able to define a qml component that applies a shadow to any source

Here is the code:

Window{
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Item
    {
        id: mainRectangle
        anchors.centerIn: parent
        width: loaderId.width + 60
        height: loaderId.height + 60

        Rectangle {
            id: rect2
            anchors.right: mainRectangle.right
            anchors.top: mainRectangle.top
            anchors.rightMargin: -30
            anchors.topMargin: -30
            width: 100
            height: 100
            color: "red"
            opacity: 0.5
        }

        Loader {
            id: loaderId
            anchors.centerIn: parent
            sourceComponent: component
            active:true
        }
        visible: false
    }

    ShaderEffectSource {
        id: shader
        anchors.fill: mainRectangle
        anchors.margins: -30
        sourceItem: mainRectangle
        opacity: 0.5
        visible: true
    }

    Component {
        id: component
        Rectangle {
            id: rect
            width: 100
            height: 100
            color: "black"
            MouseArea {
                anchors.fill: parent
                onClicked: {
                    console.log("Clicked!")
                    // call a signal from here
                }
            }
        }
    }
}

In the end the should show what it does now and the mouseArea should work.

Answer 1

onClicked in the example below is not entered when i click on the rectangle.

mainRectangle is not visible, and items that aren't visible don't get input events. Since the MouseArea is a child of mainRectangle , it won't get events either.

In the end the should show what it does now and the mouseArea should work.

Instead of hiding the source item and using ShaderEffectSource , you can set the opacity directly on mainRectangle and use item layers (the link has a similar example) to ensure that there is no overlap due to transparency:

import QtQuick 2.0
import QtQuick.Window 2.0

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Item {
        id: mainRectangle
        anchors.centerIn: parent
        width: loaderId.width + 60
        height: loaderId.height + 60
        opacity: 0.5
        layer.enabled: true

        Rectangle {
            id: rect2
            anchors.right: mainRectangle.right
            anchors.top: mainRectangle.top
            anchors.rightMargin: -30
            anchors.topMargin: -30
            width: 100
            height: 100
            color: "red"
        }

        Loader {
            id: loaderId
            anchors.centerIn: parent
            sourceComponent: component
            active: true
        }
    }

    Component {
        id: component
        Rectangle {
            id: rect
            width: 100
            height: 100
            color: "black"
            MouseArea {
                anchors.fill: parent
                onClicked: {
                    console.log("Clicked!")
                    // call a signal from here
                }
            }
        }
    }
}