plasma-framework/declarativeimports/plasmacomponents/qml/TabGroup.qml

/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the Qt Components project.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
**     the names of its contributors may be used to endorse or promote
**     products derived from this software without specific prior written
**     permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
** $QT_END_LICENSE$
**
****************************************************************************/

/**Documented API
Inherits:
        Item

Imports:
        QtQuick 1.1

Description:
        Provides a set of pages for a tab-based interface.
        A tabbed interface is made up of tab buttons plus content for each button. A TabGroup component has, as its children, each page of content in the interface. These pages can be any QML items but are typically Page components for a single page of content or PageStack components when a hierarchical navigation system is required for the tab content.
        If you use Page components for your tab content, the status property of each page is updated appropriately when the current tab is changed: the current page has status PageStatus.Active and other pages have the status PageStatus.Inactive. During page transitions, PageStatus.Activating (for the page that is becoming the current page) and PageStatus.Deactivating (for the page that was the current page) statuses are also set.

Properties:
        Item currentTab:
        The tab that is currently active and visible to the user.
        The currentTab property is initialized to null and is automatically set to point to the first tab when content is added. You can set the currentTab at any time to activate a particular tab.

**/

import QtQuick 1.1
import "private/TabGroup.js" as Engine

import "." 0.1

Item {
    id: root
    property Item currentTab

    property list<Item> privateContents
    // Qt defect: cannot have list as default property
    default property alias privateContentsDefault: root.privateContents

    onChildrenChanged: {
        //  [0] is containerHost
        if (children.length > 1)
            Engine.addTab(children[1])
    }

    onPrivateContentsChanged: {
        Engine.ensureContainers()
    }

    Component.onCompleted: {
        // Set first tabs as current if currentTab is not set by application
        if (currentTab == null && containerHost.children[0] && containerHost.children[0].children[0])
            currentTab = containerHost.children[0].children[0]
        priv.complete = true;
    }

    Item {
        id: containerHost
        objectName: "containerHost"
        anchors.fill: parent
    }

    Component {
        id: tabContainerComponent
        Item {
            id: tabContainerItem

            onChildrenChanged: {
                if (children.length == 0)
                    Engine.removeContainer(tabContainerItem)

                else if (children.length == 1) {
                    children[0].width = width
                    children[0].height = height
                    // tab content created. set the first tab as current (if not set before, and if
                    // child is added after TabGroup has completed)
                    if (priv.complete && root.currentTab == null)
                        root.currentTab = children[0]
                }
            }

            onWidthChanged: {
                if (children.length > 0)
                    children[0].width = width
            }

            onHeightChanged: {
                if (children.length > 0)
                    children[0].height = height
            }

            Component.onDestruction: {
                if (typeof(root) != "undefined" && !root.currentTab) {
                    // selected one deleted. try to activate the neighbour
                    var removedIndex = -1
                    for (var i = 0; i < containerHost.children.length; i++) {
                        if (containerHost.children[i] == tabContainerItem) {
                            removedIndex = i
                            break
                        }
                    }
                    var newIndex = -1
                    if (removedIndex != -1) {
                        if (removedIndex != containerHost.children.length - 1)
                            newIndex = removedIndex + 1
                        else if (removedIndex != 0)
                            newIndex = removedIndex - 1
                    }

                    if (newIndex != -1)
                        root.currentTab = containerHost.children[newIndex].children[0]
                    else
                        root.currentTab = null
                }
            }

            function incomingDone() {
                state = ""
                if (priv.incomingPage) {
                    if (priv.incomingPage.status != undefined) {
                        priv.incomingPage.status = PageStatus.Active
                    }
                    priv.incomingPage = null
                }
            }

            function outgoingDone() {
                if (priv.outgoingPage) {
                    if (priv.outgoingPage.status != undefined) {
                        priv.outgoingPage.status = PageStatus.Active
                    }
                    priv.outgoingPage.visible = false
                    priv.outgoingPage = null
                }
                state = "HiddenLeft"
            }

            width: parent ? parent.width : 0
            height: parent ? parent.height : 0
            state: "HiddenLeft"

            states: [
                State { name: ""; PropertyChanges { target: tabContainerItem; opacity: 1.0; x: 0 } },
                State { name: "Incoming"; PropertyChanges { target: tabContainerItem; opacity: 1.0; x: 0 } },

                State {
                    name: "OutgoingLeft"
                    PropertyChanges {
                        target: tabContainerItem
                        opacity: 0.0
                        x: -root.width
                    }
                },
                State {
                    name: "OutgoingRight"
                    PropertyChanges {
                        target: tabContainerItem
                        opacity: 0.0
                        x: root.width
                    }
                },

                State { name: "HiddenLeft"; PropertyChanges { target: tabContainerItem; opacity: 0.0; x: root.width } },
                State { name: "HiddenRight"; PropertyChanges { target: tabContainerItem; opacity: 0.0; x: -root.width } }
            ]

            transitions:  [
                Transition {
                    to: "Incoming"
                    SequentialAnimation {
                        ScriptAction { script: root.clip = true }
                        PropertyAnimation { properties: "opacity,x"; easing.type: Easing.InQuad; duration: 250 }
                        ScriptAction { script: {incomingDone(); root.clip = false} }
                    }
                },
                Transition {
                    to: "OutgoingLeft,OutgoingRight"
                    SequentialAnimation {
                        PropertyAnimation { properties: "opacity,x"; easing.type: Easing.InQuad; duration: 250 }
                        ScriptAction { script: outgoingDone() }
                    }
                }
            ]
        }
    }

    QtObject {
        id: priv
        property bool reparenting: false
        property bool complete: false
        property Item currentTabContainer: root.currentTab ? root.currentTab.parent : null
        property int currentIndex: 0
        property Item incomingPage
        property Item outgoingPage
        property bool animate: true

        onCurrentTabContainerChanged: {
            var newCurrentIndex = 0
            for (var i = 0; i < containerHost.children.length; i++) {
                if (containerHost.children[i] == currentTabContainer) {
                    newCurrentIndex = i
                    break
                }
            }

            currentTabContainer.visible = true
            incomingPage = currentTabContainer.children[0]
            incomingPage.visible = true
            if (incomingPage.status != undefined) {
                incomingPage.status = PageStatus.Activating
            }
            if (currentIndex < newCurrentIndex) {
                currentTabContainer.state = "HiddenLeft"
            } else {
                currentTabContainer.state = "HiddenRight"
            }
            if (animate) {
                currentTabContainer.state = "Incoming"
            } else {
                currentTabContainer.incomingDone()
            }

            if (newCurrentIndex == currentIndex) {
                return
            }

            var oldPage = containerHost.children[currentIndex]
            outgoingPage = oldPage.children[0]
            if (animate) {
                if (currentIndex < newCurrentIndex) {
                    oldPage.state = "OutgoingLeft"
                } else {
                    oldPage.state = "OutgoingRight"
                }
            } else {
                oldPage.outgoingDone()
            }
            currentIndex = newCurrentIndex
        }
    }
}