内容

• 特性
• 信号
• 方法
• 详细描述

Dial QML Type

Circular dial that is rotated to set a value. 更多...

导入语句：	import QtQuick.Controls 2.15
Since:	Qt 5.7
继承：	Control

• 所有成员列表，包括继承成员

特性

• angle : real
• from : real
• handle : Item
• inputMode : enumeration
• live : bool
• position : real
• pressed : bool
• snapMode : enumeration
• stepSize : real
• to : real
• value : real
• wrap : bool

信号

• moved ()

方法

• void decrease ()
• void increase ()

详细描述

The Dial is similar to a traditional dial knob that is found on devices such as stereos or industrial equipment. It allows the user to specify a value within a range.

The value of the dial is set with the value property. The range is set with the from and to properties. To enable or disable wrapping, use the wrap 特性。

The dial can be manipulated with a keyboard. It supports the following actions:

动作	Key
Decrease value by stepSize	Qt.Key_Left
Decrease value by stepSize	Qt.Key_Down
Set value to from	Qt.Key_Home
Increase value by stepSize	Qt.Key_Right
Increase value by stepSize	Qt.Key_Up
Set value to to	Qt.Key_End

Dial supports three input modes : Dial.Circular , Dial.Horizontal and Dial.Vertical . The circular input mode operates on an absolute input system, where the position of the cursor within the dial directly reflects its value. The horizontal and vertical input modes use a relative input system, where changes in the cursor's position are "added" to the value of the dial.

The following image illustrates the directions in which the various input modes track movement:

另请参阅 Customizing Dial and 输入控件 .

特性文档编制

[read-only] angle : real

This property holds the angle of the handle.

The range is from -140 degrees to 140 度。

另请参阅 position .

from : real

This property holds the starting value for the range. The default value is 0.0 .

另请参阅 to and value .

handle : Item

This property holds the handle of the dial.

The handle acts as a visual indicator of the position of the dial.

另请参阅 Customizing Dial .

inputMode : enumeration

This property holds the input mode.

Dial supports three input modes: Dial.Circular , Dial.Horizontal and Dial.Vertical . The circular input mode operates on an absolute input system, where the position of the cursor within the dial directly reflects its value. The horizontal and vertical input modes use a relative input system, where changes in the cursor's position are "added" to the value of the dial.

The following image illustrates the directions in which the various input modes track movement:

默认值为 Dial.Circular .

该特性在 QtQuick.Controls 2.5 (Qt 5.12) 引入。

live : bool

This property holds whether the dial provides live updates for the value property while the handle is dragged.

默认值为 true .

This property was introduced in QtQuick.Controls 2.2 (Qt 5.9).

另请参阅 value .

[read-only] position : real

This property holds the logical position of the handle.

The position is expressed as a fraction of the control's angle range (the range within which the handle can be moved) in the range 0.0 - 1.0 .

另请参阅 value and angle .

pressed : bool

This property holds whether the dial is pressed.

The dial will be pressed when either the mouse is pressed over it, or a key such as Qt.Key_Left is held down. If you'd prefer not to have the dial be pressed upon key presses (due to styling reasons, for example), you can use the Keys attached property :

Dial {
    Keys.onLeftPressed: {}
}
					

This will result in pressed only being true upon mouse presses.

snapMode : enumeration

This property holds the snap mode.

The snap mode works with the stepSize to allow the handle to snap to certain points along the dial.

可能的值：

常量	描述
Dial.NoSnap	The dial does not snap (default).
Dial.SnapAlways	The dial snaps while the handle is dragged.
Dial.SnapOnRelease	The dial does not snap while being dragged, but only after the handle is released.

另请参阅 stepSize .

stepSize : real

This property holds the step size.

The step size determines the amount by which the dial's value is increased and decreased when interacted with via the keyboard. For example, a step size of 0.2 , will result in the dial's value increasing and decreasing in increments of 0.2 .

The step size is only respected for touch and mouse interaction when snapMode is set to a value other than Dial.NoSnap .

默认值为 0.0 , which results in an effective step size of 0.1 for keyboard interaction.

另请参阅 snapMode , increase() ，和 decrease() .

to : real

This property holds the end value for the range. The default value is 1.0 .

另请参阅 from and value .

value : real

This property holds the value in the range from - to 。默认值为 0.0 .

另请参阅 position and live .

wrap : bool

This property holds whether the dial wraps when dragged.

For example, when this property is set to true , dragging the dial past the to position will result in the handle being positioned at the from position, and vice versa:

When this property is false , it's not possible to drag the dial across the from and to values.

默认值为 false .

信号文档编制

moved ()

This signal is emitted when the dial has been interactively moved by the user by either touch, mouse, or keys.

注意： 相应处理程序是 onMoved .

This signal was introduced in QtQuick.Controls 2.2 (Qt 5.9).

方法文档编制

void decrease ()

Decreases the value by stepSize ，或 0.1 if stepSize is not defined.

另请参阅 stepSize .

void increase ()

Increases the value by stepSize ，或 0.1 if stepSize is not defined.

另请参阅 stepSize .