79 lines
2.9 KiB
QML
79 lines
2.9 KiB
QML
/*
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Copyright (C) 2012 Marco Martin <mart@kde.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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import QtQuick 1.1
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/**Documented API
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Inherits:
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Item
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Imports:
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QtQuick 1.1
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Description:
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This item can load any qml component, just like a Loader. Important difference, the component will be only loaded when the "when" property is satisfied (ie evaluates to true) in this way it's easy to have big (and memory expensive) parts of the user interface load only when a certain condition is satisfied.
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For instance the contents of the tabs of a TabBar can be loaded only when they become the current page
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Properties:
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bool when:
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Boolean condition that tells when to load the declarative component
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variant source:
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It can be a string with a path name of a qml file or a Component. It's the component that will be loaded when "when" is true. If the component changes the old instantiated component will be deleted and the new will be loaded instead.
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Item item: the item instantiated from component, if any.
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**/
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Item {
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id: root
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property alias when: loader.when
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property alias source: loader.conditionalSource
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property alias item: loader.item
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Loader {
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id: loader
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anchors.fill: parent
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property bool when: false
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property variant conditionalSource
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//internal
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property variant oldConditionalSource
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onWhenChanged: loadTimer.restart()
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onConditionalSourceChanged: loadTimer.restart()
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Timer {
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id: loadTimer
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interval: 0
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onTriggered: {
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if (loader.when &&
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(loader.item === null ||
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loader.conditionalSource !== loader.oldConditionalSource)) {
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if (typeof(loader.conditionalSource) === "string") {
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loader.source = loader.conditionalSource
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} else {
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loader.sourceComponent = loader.conditionalSource
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}
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loader.oldConditionalSource = loader.conditionalSource
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loader.item.visible = true
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loader.item.anchors.fill = loader.item.parent
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}
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}
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}
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}
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} |