path: root/src/controls/Menu.qml

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import QtQuick 2.0
import QtQuick.Controls 1.0
import QtQuick.Controls.Styles 1.0
import "Styles/Settings.js" as Settings

/*!
    \qmltype Menu
    \inqmlmodule QtQuick.Controls 1.0
    \ingroup applicationwindow
    \brief Menu provides a menu component for use in menu bars, context menus, and other popup menus.

    \code
    Menu {
        text: "Edit"

        MenuItem {
            text: "Cut"
            shortcut: "Ctrl+X"
            onTriggered: ...
        }

        MenuItem {
            text: "Copy"
            shortcut: "Ctrl+C"
            onTriggered: ...
        }

        MenuItem {
            text: "Paste"
            shortcut: "Ctrl+V"
            onTriggered: ...
        }

        MenuSeparator { }

        Menu {
            text: "More Stuff"

            MenuItem {
                text: "Do Nothing"
            }
        }
    }
    \endcode

    Note that some properties, like \c enabled, \c text, or \c iconSource, only make sense
    depending on the context in which the menu is being used. The three main use cases are
    as a \l MenuBar top-level menu, as a submenu inside another menu, or as a standalone,
    or context, menu.

    \sa MenuBar, MenuItem, MenuSeparator
*/

MenuPrivate {
    id: root

    /*! \internal */
    property Component style: Qt.createComponent(Settings.THEME_PATH + "/MenuStyle.qml", root)

    /*! \internal */
    property var __menuBar: null
    /*! \internal */
    property int __currentIndex: -1
    /*! \internal */
    on__MenuClosed: __currentIndex = -1

    /*! \internal */
    __contentItem: Loader {
        sourceComponent: __menuComponent
        active: !root.__isNative && root.__popupVisible
        focus: true
    }

    /*! \internal */
    property Component __menuComponent: Loader {
        id: menuFrameLoader

        property Style __style: styleLoader.item
        property Component menuItemStyle: __style ? __style.menuItem : null

        property var control: root
        property alias contentWidth: column.width
        property alias contentHeight: column.height

        property int subMenuXPos: width + (item && item["subMenuOverlap"] || 0)

        visible: status === Loader.Ready
        sourceComponent: __style ? __style.frame : undefined

        Loader {
            id: styleLoader
            active: !root.isNative
            sourceComponent: root.style
            onStatusChanged: {
                if (status === Loader.Error)
                    console.error("Failed to load Style for", root)
            }
        }

        focus: true
        Keys.forwardTo: __menuBar ? [__menuBar] : []
        Keys.onEscapePressed: root.__dismissMenu()

        Keys.onDownPressed: {
            if (root.__currentIndex < 0) {
                root.__currentIndex = 0
                return
            }

            for (var i = root.__currentIndex + 1;
                 i < root.items.length && !canBeHovered(i); i++)
                ;
        }

        Keys.onUpPressed: {
            for (var i = root.__currentIndex - 1;
                 i >= 0 && !canBeHovered(i); i--)
                ;
        }

        function canBeHovered(index) {
            var item = itemsRepeater.itemAt(index)
            if (!item["isSeparator"] && item.enabled) {
                root.__currentIndex = index
                return true
            }
            return false
        }

        Keys.onLeftPressed: {
            if (root.__parentMenu)
                __closeMenu()
        }

        Keys.onRightPressed: {
            var item = itemsRepeater.itemAt(root.__currentIndex)
            if (item && item.hasSubmenu) {
                item.showSubMenu(true)
                item.menuItem.__currentIndex = 0
            }
        }

        Keys.onSpacePressed: menuFrameLoader.triggerAndDismiss()
        Keys.onReturnPressed: menuFrameLoader.triggerAndDismiss()
        Keys.onEnterPressed: menuFrameLoader.triggerAndDismiss()

        function triggerAndDismiss() {
            var item = itemsRepeater.itemAt(root.__currentIndex)
            if (item && !item.isSeparator) {
                root.__dismissMenu()
                if (!item.hasSubmenu)
                    item.menuItem.trigger()
            }
        }

        Binding {
            // Make sure the styled frame is in the background
            target: menuFrameLoader.item
            property: "z"
            value: menuMouseArea.z - 1
        }

        MouseArea {
            id: menuMouseArea
            anchors.fill: parent
            hoverEnabled: true
            acceptedButtons: Qt.AllButtons

            onPositionChanged: updateCurrentItem(mouse)
            onReleased: menuFrameLoader.triggerAndDismiss()
            onExited: {
                if (currentItem && !currentItem.menuItem.__popupVisible) {
                    currentItem = null
                    root.__currentIndex = -1
                }
            }

            property Item currentItem: null

            function updateCurrentItem(mouse) {
                var pos = mapToItem(column, mouse.x, mouse.y)
                if (!currentItem || !currentItem.contains(Qt.point(pos.x - currentItem.x, pos.y - currentItem.y))) {
                    if (currentItem && !pressed && currentItem.hasSubmenu)
                        currentItem.closeSubMenu()
                    currentItem = column.childAt(pos.x, pos.y)
                    if (currentItem) {
                        root.__currentIndex = currentItem.menuItemIndex
                        if (currentItem.hasSubmenu && !currentItem.menuItem.__popupVisible)
                            currentItem.showSubMenu(false)
                    } else {
                        root.__currentIndex = -1
                    }
                }
            }

            // Each menu item has its own mouse area, and for events to be
            // propagated to the menu mouse area, they need to be embedded.
            Column {
                id: column

                Repeater {
                    id: itemsRepeater
                    model: root.items

                    Loader {
                        id: menuItemLoader

                        property var menuItem: modelData
                        property bool isSeparator: menuItem ? !menuItem.hasOwnProperty("text") : false
                        property bool hasSubmenu: menuItem ? !!menuItem["items"] : false
                        property bool selected: !isSeparator && root.__currentIndex === index

                        property int menuItemIndex: index

                        sourceComponent: menuFrameLoader.menuItemStyle
                        enabled: visible && !isSeparator && !!menuItem && menuItem.enabled
                        visible: menuItem.visible
                        active: visible

                        function showSubMenu(immediately) {
                            if (immediately) {
                                if (root.__currentIndex === menuItemIndex)
                                    menuItem.__popup(menuFrameLoader.subMenuXPos, 0, -1)
                            } else {
                                openMenuTimer.start()
                            }
                        }

                        Timer {
                            id: openMenuTimer
                            interval: 50
                            onTriggered: menuItemLoader.showSubMenu(true)
                        }

                        function closeSubMenu() { closeMenuTimer.start() }

                        Timer {
                            id: closeMenuTimer
                            interval: 1
                            onTriggered: {
                                if (root.__currentIndex !== menuItemIndex)
                                    menuItem.__closeMenu()
                            }
                        }

                        Component.onCompleted: menuItem.__visualItem = menuItemLoader
                    }
                }

                onWidthChanged: {
                    for (var i = 0; i < children.length; i++) {
                        var item = children[i]["item"]
                        if (item)
                            item.implicitWidth = Math.max(root.__minimumWidth, implicitWidth)
                    }
                }
            }
        }
    }
}