QML connect signal to function - qt

Question

I was getting my self familiar with QML in QT5. So i was trying to make the code from the follwing video: video
In this video the code:send.connect(target.receive()); is used. But This part does not work. I am getting the error:
qrc:/Receiver.qml:8: Error: Cannot assign [undefined] to QString
Is this method deprecated or am i doing something wrong?
main.qml
Window {
visible: true
width: 640
height: 480
title: qsTr("Jurassic World")
Background {
id: background
anchors.fill: parent
target: sender
Sender {
id: sender
y: 145
displayText: "Sender"
anchors.verticalCenter: parent.verticalCenter
anchors.left: parent.left
anchors.leftMargin: 50
target: receiver
}
Receiver {
id: receiver
x: 376
y: 158
displayText: "Receiver"
anchors.verticalCenter: parent.verticalCenter
anchors.right: parent.right
anchors.rightMargin: 50
width: sender.width
}
}
}
Receiver.qml
Cirkel {
id: receiveButton
function receive(value)
{
displayText = value
clicknotify.running = true
}
SequentialAnimation on buttonColor
{
id: clicknotify
running: false
ColorAnimation {
from: "#afc4cb"
to: "red"
duration: 200
}
ColorAnimation {
from: "red"
to: "#afc4cb"
duration: 200
}
}
}
Sender.qml
Cirkel {
id: sendButton
property int counter: 0
property Receiver target: null
signal send(string value)
onTargetChanged: {
send.connect(target.receive());
}
MouseArea {
anchors.fill: parent
onClicked: {
counter++
parent.send(counter)
displayText = counter
}
onPressed: parent.buttonColor = "green"
onReleased: parent.buttonColor = "#afc4cb"
}
}
Question:
How can i link a signal from one qml to a other qml function?

Answer 1

You write:
send.connect(target.receive());
where you call target.receive() and try to connect its return value to send.
What you want is:
send.connect(target.receive);
where you connect send to the function receive itself.
Recommendation:
Also try the declarative way, using a Connection-object.

Answer 2

I'd say, in Sender.qml just do:
signal send(int value)
...
sendButton.send(counter)
and in main.qml just do
Sender {
id: sender
...
onSend: receiver.receive(value)
}
That's all. No need for the whole target assignment.
And by the way, you have a data type issue in the receive function (integer to string)
Fix with this:
function receive(value)
{
displayText = "" + value
clicknotify.running = true
}
In general, a signal in QML can be handled as a function by adding "on" and uppercase first letter.
For example, a Button exposes the clicked signal, and when you handle it you use onClicked