ChildAt() in QML , a question .i need help,thank you!

hill

i am a new learner in QML, i want to make a little game.
so ,in mousearer,i want to click a Lable ,and make it to move ,i use the childAt(mouseX,mouse Y) to capture it.

but ,i do not know how to use childAt,i need help.
thank you!

sierdzio

Please, use correct interpunction, your post is very hard to read.

If you don't know how to use this at all, read the docs. If you have any specific problem, please specify what is wrong.

p3c0

Perhaps this is what you want,

@
import QtQuick 2.0
import QtQuick.Controls 1.0

Rectangle {
width: 800
height: 480
Text {
text: qsTr("Drag the two labels")
anchors.centerIn: parent
}

Label {
    id: l1
    text: "Label 1"
    x: 50
    y: 50
    width: 100
    height: 100
    color: "red"

    MouseArea {
        anchors.fill: parent
        property variant previousPosition
        onPressed: {
            previousPosition = Qt.point(mouseX, mouseY)
        }
        onPositionChanged: {
            if (pressedButtons == Qt.LeftButton) {
                var dx = mouseX - previousPosition.x
                var dy = mouseY - previousPosition.y
                l1.x = l1.x + dx;
                l1.y = l1.y + dy;
            }
        }
    }
}

Label {
    id: l2
    text: "Label 2"
    x: 100
    y: 100
    width: 100
    height: 100
    color: "orange"

    MouseArea {
        anchors.fill: parent
        property variant previousPosition
        onPressed: {
            previousPosition = Qt.point(mouseX, mouseY)
        }
        onPositionChanged: {
            if (pressedButtons == Qt.LeftButton) {
                var dx = mouseX - previousPosition.x
                var dy = mouseY - previousPosition.y
                l2.x = l2.x + dx;
                l2.y = l2.y + dy;
            }
        }
    }
}

}

@

hill

Thank you ,p3c0!
But,i want to automatically capture the Lable ,which in the Rectangle.
eg: l1 is captured by (mouseX,mouseY).
so i think childAt() can be used. But i cannot use it.

p3c0

Sorry but i didn't get you. In your first post you said you want to click the label and and move it.
How would you get the X an Y coordinates of the item unless you click it or you know in advance the position of each label ?
Can you elaborate more your problem ?

hill

hi,p3c0.
thank you for your help.
in my program. i defined 7 lables.

Mousearea{
anchors.fill:parent
onClicked:{
var click;
click = mapToItem(parent,mouseX,mouseY);
parent.childAt(click.x,click.y).anchors.leftMargin = 50;
...
}
}

like these,i want capture a lable by (mouseX,mouseY),but ,in running,
my program return wrong value.

p3c0

Hi,

Considering your requirement i implemented the following and it gives the item (its objectName )when clicked on it,

@
import QtQuick 2.0
import QtQuick.Controls 1.0

Rectangle {
id: rect
width: 800
height: 480
Text {
text: qsTr("Click on each item")
anchors.centerIn: parent
}

MouseArea {
    anchors.fill: parent
    onClicked: {
        var click;
        click = mapToItem(parent,mouseX,mouseY)
        var obj = parent.childAt(mouseX,mouseY)
        console.log(obj.objectName)
    }
}

Label {
    id: l1
    objectName: "l1"
    text: "Label 1"
    x: 50
    y: 50
    width: 100
    height: 100
    color: "red"
}

Label {
    id: l2
    objectName: "l2"
    text: "Label 2"
    x: 100
    y: 100
    width: 100
    height: 100
    color: "orange"
}

Rectangle {
    objectName: "r2"
    width: 200
    height: 200
    x: 500
    y: 100
    color: "red"
}

}
@

The MouseArea code is similar to your's but i moved it to the top before adding the two labels and the rect. If i move the MouseArea code after creation of labels and the rect it gives QQuickMouseArea as the child.
Hope this is what you want.

hill

Thank you, p3c0.
your answer is my need ,thank you so much!