GUI enabling/disabling of controls: Difference between revisions

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{{omit from|GUISS|Can only do what the installed applications can do}}

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In addition to fundamental [[GUI component interaction]], an application should

dynamically enable and disable GUI components, to give some guidance to the

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of the application.

The task: Similar to the task [[GUI component interaction]] write a program ~~that~~

The task: Similar to the task [[GUI component interaction]] write a program

presents a form with three components to the user: ~~A numeric input field~~

that presents a form with three components to the user:

("Value") and two buttons ("increment" and "decrement").

A numeric input field ("Value") and two buttons ("increment" and "decrement").

The field is initialized to zero. ~~The user may manually enter a new value into~~

The field is initialized to zero.

The user may manually enter a new value into the field,

the field, increment its value with the "increment" button, or decrement the

value with the "~~decrement~~" button.

increment its value with the "increment" button,

or decrement the value with the "decrement" button.

The input field should be enabled only when its value is zero. ~~The "increment"~~

The input field should be enabled only when its value is zero.

button only as long as the field's value is less then 10: ~~When the value 10 is~~

The "increment" button only as long as the field's value is less then 10:

reached, the button should go into a disabled state. ~~Analogously, the~~

When the value 10 is reached, the button should go into a disabled state.

"decrement" button should be enabled only as long as ~~the value is greater than~~

Analogously, the "decrement" button should be enabled only as long as

the value is greater than zero.

zero.

Effectively, the user can now either increment up to 10, or down to zero.

Manually entering values outside that range is still legal, ~~but the buttons~~

Manually entering values outside that range is still legal,

should reflect that and enable/disable accordingly.

but the buttons should reflect that and enable/disable accordingly.

=={{header|Ada}}==

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SYS "SetDlgItemInt", !form%, 101, number% - 1, 1

ENDPROC</lang>

Output:

<p>

[[File:Guienabbc.gif]]

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=={{header|Scala}}==

[[Category:Scala Implementations]]

<lang Scala>import swing.{ BoxPanel, Button, GridPanel, Orientation, Swing, TextField }

import swing.event.{ ButtonClicked, Key, KeyPressed, KeyTyped }

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updateEnables; # Force initial state of buttons</lang>

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=={{header|Visual Basic}}==

In VB, windows are usually created in the IDE. ~~The generated code is hidden from the user unless viewed outside of VB. For the sake of this task, I have included that code.~~

In VB, windows are usually created in the IDE.

The generated code is hidden from the user unless viewed outside of VB.

For the sake of this task, I have included that code.

(Also, this sort of task would typically be performed ~~by a "spinner" or "up-down" control, not by buttons.)~~

(Also, this sort of task would typically be performed

by a "spinner" or "up-down" control, not by buttons.)

<lang vb>VERSION 5.00

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End Select

End Sub</lang>

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{{omit from|GUISS|Can only do what the installed applications can do}}

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