Stepper Box

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The Stepper Box lets the operator raise or lower a number in fixed steps with two buttons. It is found in the Input - OpenBridge section of the Perspective Component Palette as Stepper Box.

The parts of the stepper:

1. Decrease button — to the left. Lowers the value by stepDown.
2. Value — the number, with an optional unit. It cannot be typed in. See Value and Steps.
3. Increase button — to the right. Raises the value by stepUp.
4. Helper text — below the stepper. See Unit and Helper Text.

The Stepper Box is one of the input components. How values are written back, events, disabling and the behavior in the Designer are shared by all of them and are described in Input Components — Common Features. This page covers what is specific to the Stepper Box.

A Stepper Box dropped from the palette goes from 0 to 100 in steps of 1 and is set to 50:

The stepper is as wide as the component; the value takes the space between the buttons. The blue frame is the component’s box:

120 px wide	300 px wide

Value and Steps

value is the number shown. A click on the increase button adds stepUp to it, a click on the decrease button subtracts stepDown. The two steps can be different. Bind value bidirectionally to a tag to connect the stepper to it (see Values).

The operator changes the value only with the buttons: the number cannot be typed. Use a Number Input Field where the operator must type a number, or a Slider for a coarse setting.

Each click is one step. Holding a button down does not repeat the step.

Limits

The value stays between min and max. A step that would pass a limit stops at the limit: with max = 100 and stepUp = 5, a click at 98 gives 100. At a limit the button that leads further is disabled:

At min	At max

A value written by a binding is not limited: it is shown as it is, also outside the range. The first click then brings it to the nearest limit.

Note: The buttons need a value to step from. While value is empty, for instance when a bound tag has no value, both buttons are disabled.

Keyboard

When the stepper has focus, the Up and Down arrow keys step the value as the buttons do.

Note: After a click on the number itself, the arrow keys still write the new value, but the number shown is not updated. Use the buttons where the operator has a pointer or a touch screen.

Properties

Name	Description	Property Type
value	Current value. Written when the operator clicks a button. Default 50.	value
stepUp	How much a click on the increase button adds. Default 1.	value
stepDown	How much a click on the decrease button subtracts. Default 1.	value
min	Lowest value. Default 0.	value
max	Highest value. Default 100.	value

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Type

type selects the icons on the buttons. The left button always lowers the value and the right button always raises it.

type
plus-minus (default)	Minus and plus. For a quantity or a setpoint.
left-right	Arrows left and right. For stepping through a series.
up-down	Arrows down and up. For a level or a height.

Properties

Name	Description	Property Type
type	plus-minus, left-right or up-down. Default plus-minus.	value

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Unit and Helper Text

unit is a text shown after the number. helperText is shown centred below the stepper; make the component about 72 px tall to give it room.

Unit	Helper text

The number is shown as it is, without a number format. With a step that is not a whole number, such as 0.1, choose min, max and the steps so that the values are the ones you want to show.

Note: placeholder is meant to be shown while value is empty. No placeholder was shown when tested.

Properties

Name	Description	Property Type
unit	Text shown after the number, for example kn. Empty by default.	value
helperText	Text below the stepper. Empty by default.	value
placeholder	Hint for an empty stepper. See the note above.	value

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Read-only and Disabled

readonly	disabled

Both stop the operator from changing the value: the buttons are disabled and no events are fired. With readonly the number keeps its normal colour, so it reads as a value that is shown but not editable here. With disabled the whole stepper is dimmed. See Disabled.

Properties

Name	Description	Property Type
readonly	Disable the buttons without dimming the number. Default false.	value

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Common Properties

These work in the same way on every input component, and are described in Input Components — Common Features:

• Disabled — disabled.
• Appearance — style.

Component Events

Every click on a button writes value and then fires two events: onActionPerformed, and onUp or onDown.

Event	Description	Event Object
onActionPerformed	Fired when the operator changes the value, with either button.	—
onUp	Fired when the increase button changed the value.	—
onDown	Fired when the decrease button changed the value.	—

No event is fired for a click on a disabled button, for instance at max.

See Events.

Examples

Example 1 — Speed Limit in Steps of 0.5 kn

1. Drop a Stepper Box into the view and make it about 200 × 72 px.
2. Set min to 0, max to 20, and stepUp and stepDown to 0.5.
3. Set unit to kn and helperText to Speed limit.
4. Bind value to the tag [default]Pump01/Setpoint and enable Bidirectional.

Example 2 — Step Through Pages

1. Drop a Stepper Box into the view and set type to left-right.
2. Set min to 1, max to the number of pages and value to 1.
3. Bind value bidirectionally to a custom property of the view, for example view.custom.page, and use that property to choose what the view shows.