Details
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Bug
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Resolution: Done
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P2: Important
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None
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5.15.8
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mac OS 12.2, Xcode 13.0
Description
I'm investigating a problem were all my apps take some time to become responsive. The more complex the app is, the more time it takes to get responsive to touch.
I've parted from a simple Qt Quick application to demonstrate this issue. The attached example is nothing more than a ColumnLayout with a Repeater inside.
When the number of items is bigger then a certain number, the application takes several seconds to become responsive. The increase in the number of items seems to cause an exponential increase in time to become responsive.
These are some of the tested model sizes and respective results:
import QtQuick 2.15 import QtQuick.Window 2.15 import QtQuick.Layouts 1.15 Window { width: 640 height: 480 visible: true title: qsTr("Hello World") ColumnLayout { anchors.fill: parent spacing: 1 Repeater { //model: 10 // ok //model: 100 // ok //model: 1000 // ok //model: 10000 // ok //model: 12500 // ok //model: 25000 // more than 5 seconds to become responsive //model: 50000 // more than 20 seconds to become responsive model: 100000 // 1.5 minutes to become responsive delegate: Rectangle { Layout.fillWidth: true Layout.preferredHeight: 1 color: "black" } } } Rectangle { anchors.fill: parent color: "transparent" opacity: 0.5 MouseArea { anchors.fill: parent onPressed: parent.color = "gray" onReleased: parent.color = "transparent" } } }
Note 1: This does not happen in Android, Windows or Mac platforms.
Note 2: It is important to refer that this didn't happen in previous versions of Qt. I can't recall exactly when this started to happen on iOS
Note 3: While it is not a show stopper, some users have been complaining of inability to interact with our apps in the first couple of seconds, which is definitely bad for reputation.