Spinbox

A spinbox widget allows users to choose numbers (or, in fact, items from an arbitrary list). It does this by combining an entry-like widget showing the current value with a pair of small up/down arrows, which can be used to step through the range of possible choices.

Spinbox widgets

Spinbox widgets are created using the add_ttk_spinbox method:

#![allow(unused)]
fn main() {
parent.add_ttk_spinbox( "s" -from(1.0) -to(100.0) -textvariable("spinval") )?;
}

Like scale widgets, spinboxes let users choose a number between a certain range (specified using the from and to configuration options), though through a very different user interface. You can also specify an increment, which controls how much the value changes every time you click the up or down button.

Like a listbox or combobox, spinboxes can also be used to let users choose an item from an arbitrary list of strings; these can be specified using the values configuration option. This works in the same way it does for comboboxes; specifying a list of values will override to from and to settings.

In their default state, spinboxes allow users to select values either via the up and down buttons, or by typing them directly into the entry area that displays the current value. If you'd like to disable the latter feature, so that only the up and down buttons are available, you can set the TtkState::ReadOnly state flag.

#![allow(unused)]
fn main() {
s.set_state( TtkState::ReadOnly )?;
}

Like other themed widgets, you can also disable spinboxes, via the TtkState::Disabled state flag, or check the state via the instate method. Spinboxes also support validation in the same manner as entry widgets, using the validate and validatecommand configuration options.

You might be puzzled about when to choose a scale, listbox, combobox, entry, or a spinbox. Often, several of these can be used for the same types of data. The answer really depends on what you want users to select, platform user interface conventions, and the role the value plays in your user interface.

For example, both a combobox and a spinbox take up fairly small amounts of space compared with a listbox. They might make sense for a more peripheral setting. A more primary and prominent choice in a user interface may warrant the extra space a listbox occupies. Spinboxes don't make much sense when items don't have a natural and obvious ordering to them. Be careful about putting too many items in both comboboxes and spinboxes. This can make it more time consuming to select an item.

There is a boolean wrap option that determines whether the value should wrap around when it goes beyond the starting or ending values. You can also specify a width for the entry holding the current value of the spinbox.

Again there are choices as to how to set or get the current value in the spinbox. Normally, you would specify a linked variable with the textvariable configuration option. As usual, any changes to the variable are reflected in the spinbox, while any changes in the spinbox are reflected in the linked variable. As well, the set( value ) and get() methods allow you to set or get the value directly.

Spinboxes generate virtual events when users press up (event::virtual_event("Increment")) or down (event::virtual_event("Decrement")). A command configuration option allows you to provide a callback that is invoked on any changes.

Run Example

cargo run --example spinbox