内容

• 特性
• 方法
• 详细描述
• Populating the Menu
• Displaying the Menu

PieMenu QML Type

A popup menu that displays several menu items along an arc. 更多...

import 语句：	import QtQuick.Extras 1.4
Since:	Qt 5.5
继承：	FocusScope

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特性

• boundingItem : Item
• currentIndex : int
• currentItem : int
• menuItems : list<MenuItem>
• selectionAngle : real
• style : Component
• title : string
• triggerMode : int

方法

• void addItem (string text )
• void insertItem (int before , string text )
• void popup (real x , real y )
• void removeItem ( item )

详细描述

The PieMenu provides a radial context menu as an alternative to a traditional menu. All of the items in a PieMenu are an equal distance from the center of the control.

Populating the Menu

To create a menu, define at least one MenuItem as a child of it:

PieMenu {
    id: pieMenu
    MenuItem {
        text: "Action 1"
        onTriggered: print("Action 1")
    }
    MenuItem {
        text: "Action 2"
        onTriggered: print("Action 2")
    }
    MenuItem {
        text: "Action 3"
        onTriggered: print("Action 3")
    }
}
					

By default, only the currently selected item's text is displayed above the menu. To provide text that is always visible when there is no current item, set the title 特性。

Displaying the Menu

The typical use case for a menu is to open at the point of the mouse cursor after a right click occurs. To do that, define a MouseArea that covers the region upon which clicks should open the menu. When the MouseArea is right-clicked, call the popup() 函数：

MouseArea {
    anchors.fill: parent
    acceptedButtons: Qt.RightButton
    onClicked: pieMenu.popup(mouseX, mouseY)
}
					

If the menu is opened in a position where some of its menu items would be outside of boundingItem , it is automatically moved to a position where they will not be hidden. By default, the boundingItem is set to the parent of the menu. It can also be set to null to prevent this behavior.

PieMenu can be displayed at any position on the screen. With a traditional context menu, the menu would be positioned with its top left corner at the position of the right click, but since PieMenu is radial, we position it centered over the position of the right click.

要创建 PieMenu that opens after a long press and selects items upon releasing, you can combine ActivationMode.ActivateOnRelease with a MouseArea using a Timer:

MouseArea {
    id: touchArea
    anchors.fill: parent
    Timer {
        id: pressAndHoldTimer
        interval: 300
        onTriggered: pieMenu.popup(touchArea.mouseX, touchArea.mouseY);
    }
    onPressed: pressAndHoldTimer.start()
    onReleased: pressAndHoldTimer.stop();
}
PieMenu {
    id: pieMenu
    triggerMode: TriggerMode.TriggerOnRelease
    MenuItem {
        text: "Action 1"
        onTriggered: print("Action 1")
    }
    MenuItem {
        text: "Action 2"
        onTriggered: print("Action 2")
    }
    MenuItem {
        text: "Action 3"
        onTriggered: print("Action 3")
    }
}
					

You can hide individual menu items by setting their visible property to false . Hiding items does not affect the startAngle or endAngle ; the remaining items will grow to consume the available space.

You can create a custom appearance for a PieMenu by assigning a PieMenuStyle

特性文档编制

boundingItem : Item

The item which the menu must stay within.

A typical use case for PieMenu involves:

• A MouseArea that determines the clickable area within which the menu can be opened.
• The bounds that the menu must not go outside of.

Although they sound similar, they have different purposes. Consider the example below:

The user can only open the menu within the inner rectangle. In this case, they've opened the menu on the edge of the MouseArea , but there would not be enough room to display the entire menu centered at the cursor position, so it was moved to the left.

If for some reason we didn't want this restriction, we can set boundingItem to null :

By default, the menu's parent is the boundingItem.

[read-only] currentIndex : int

The index of the the menu item that is currently under the mouse, or -1 if there is no such item.

[read-only] currentItem : int

The menu item that is currently under the mouse, or null if there is no such item.

[default] menuItems : list < MenuItem >

The list of menu items displayed by this menu.

You can assign menu items by declaring them as children of PieMenu :

PieMenu {
    MenuItem {
        text: "Action 1"
        onTriggered: function() { print("Action 1"); }
    }
    MenuItem {
        text: "Action 2"
        onTriggered: function() { print("Action 2"); }
    }
    MenuItem {
        text: "Action 3"
        onTriggered: function() { print("Action 3"); }
    }
}
									

[read-only] selectionAngle : real

This property reflects the angle (in radians) created by the imaginary line from the center of the menu to the position of the cursor.

Its value is undefined when the menu is not visible.

style : Component

The style Component for this control.

另请参阅 Qt Quick Controls Styles QML Types .

title : string

This property defines the text that is shown above the menu when there is no current menu item ( currentIndex is -1 ).

默认值为 "" (an empty string).

triggerMode : int

This property determines the method for selecting items in the menu.

• A triggerMode of TriggerMode.TriggerOnPress means that menu items will only be selected when a mouse press event occurs over them.
• A triggerMode of TriggerMode.TriggerOnRelease means that menu items will only be selected when a mouse release event occurs over them. This means that the user must keep the mouse button down after opening the menu and release the mouse over the item they wish to select.
• A triggerMode of TriggerMode.TriggerOnClick means that menu items will only be selected when the user clicks once over them.

警告： Changing the triggerMode while the menu is visible will result in undefined behavior.

方法文档编制

void addItem ( string text )

Adds an item to the end of the menu items.

Equivalent to passing calling insertItem(menuItems.length, text) .

Returns the newly added item.

void insertItem ( int before , string text )

插入 MenuItem with text before the index at before .

To insert an item at the end, pass menuItems.length .

Returns the newly inserted item, or null if before 无效。

void popup ( real x , real y )

Opens the menu at coordinates x , y .

void removeItem ( item )

移除 item from the menu.