[nks (baumemo)]

Hi,

I have a strange issue with the SwipeView component. When using with a other default index set by binding the onItemChanged event get triggered with null item.

What do I wrong. What can I do to get always a valid item? May be it is a bug?

The output is:

2
null
2
null

The Code:

import Felgo 3.0
import QtQuick 2.15
import QtQuick.Controls 2.15 as QQC

App {
    Page {
        id: currentPage
        title: "Demo"
        property int swipeDefaultIndex:2


        QQC.SwipeView {
            id: swipeView

            currentIndex: currentPage.swipeDefaultIndex
            anchors.fill: parent

            onCurrentItemChanged: {
                console.log(currentIndex)
                console.log(currentItem)
            }
            onCurrentIndexChanged: {
                console.log(currentIndex)
                console.log(currentItem)
            }

            Repeater {
                model: 7
                Item {

                }
            }
        }
    }
}

 

 

 

[AlexFelgo Team]

Hi,

indeed this looks like a bug in the Qt SwipeView, when initializing the view with a custom currentIndex. I extended the example a bit to further check that:

import Felgo 3.0
import QtQuick 2.15
import QtQuick.Controls 2.15 as QQC

App {
  Page {
    id: currentPage
    title: "Demo"
    property int swipeDefaultIndex:2

    Component.onCompleted: {
      // Using this will correctly trigger the signals, but will show visual transitions
      //swipeView.currentIndex = Qt.binding(function() {return currentPage.swipeDefaultIndex})
    }

    QQC.SwipeView {
      id: swipeView

      currentIndex: currentPage.swipeDefaultIndex
      anchors.fill: parent

      onCurrentItemChanged: {
        console.debug("onCurrentItemChanged")
        // You could ignore any calls where !currentItem
        console.log(currentIndex)
        console.log(currentItem)
      }
      onCurrentIndexChanged: {
        console.debug("onCurrentIndexChanged")
        // You could ignore any calls where !currentItem
        console.log(currentIndex)
        console.log(currentItem)
      }

      // Call this manually after completion will trigger again with correct data
      Component.onCompleted: currentItemChanged()

      Repeater {
        model: 7
        Item {

          Rectangle {
            anchors.fill: parent
            color: Qt.rgba(1,0,0,0.1*(index+1))
          }
        }
      }
    }

    Column {
      anchors.centerIn: parent

      AppButton {
        text: "Next"
        onClicked: currentPage.swipeDefaultIndex++
      }

      AppButton {
        text: "Prev"
        onClicked: currentPage.swipeDefaultIndex--
      }

      AppButton {
        text: "CurrentItem"
        onClicked: console.log(swipeView.currentItem)
      }
    }
  }
}

Manually triggering the signal after the component is completed seems to return the correct data, so that might be an option for you?

Best,
Alex