An unusual effect of a component over another in a QML program

JavaScript
1

Hi all,

I’m new here and hope here will be helpful for me. :slight_smile:
I’m also new in QML which is mostly JavaScript code and I try to explain the problem with one of my programs so that I can solve it with your help.

Here is a QML project on Qt Creator 4.8.1 on the Widows machine.

Here is Ball.qml:

import QtQuick 2.12
 
Rectangle {
width: 18; height: 18
color: "white"
radius: width/2
 
Timer {   // This timer's job is merely moving the ball
     id: timer
     interval: 22; repeat: true; running: true
 
 onTriggered: {
     parent.x +=  0.88
     parent.y +=  0.88
   }
  }
}

Racket.qml:

import QtQuick 2.12
 
Rectangle {
id: root
width: 15; height: 65
 
MouseArea {
    anchors.fill: root
 
    drag.target: root
    drag.axis: Drag.YAxis
    drag.minimumY: table.y
    drag.maximumY: table.height - root.height - 10
 }
}

main.qml:

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.5
 
Window {
id: window
visible: true
width: 1000; height: 800
color: "gray"
 
    // The components
    // --------------
 
    Rectangle {
        id: table
        anchors.fill: parent
        anchors.margins: 10
        y: 10
        anchors.horizontalCenter: parent.horizontalCenter
        color: "royalblue"
    }
    Racket {
        id: blackRacket
        anchors.left: table.left
        anchors.leftMargin: width * 2
        y: table.height / 2
        color: "black"
    }
    Racket {
        id: redRacket
        anchors.right: table.right
        anchors.rightMargin: width * 2
        y: table.height / 2
        color: "red"
    }
    Ball {
        id: ball
      x: 150
     y: 150
    }
}

I tested that on my Android device (a tablet running Android 4.4.2). The problem is that, when rackets are not moving the ball moves smoothly (and it’s OK), but when I move either racket, it affects the speed of the ball, strangely and reduces ball’s speed! These two must be independent in terms of movement and speed, but in effect this issue takes place. I don’t know why.

Will you test this code on your Android device too, to see if the problem exits there as well. If yes, what could be the source of the issue and how to remedy that, please?

Thanks beforehand.

2

Isn’t there any solution for this problem, please? :frowning: