inputfieldsandbuttons.C
creates three buttons at the bottom of the window,
using a factory's
create_button() method which returns a new
x::w::button.
create_button()'s first parameter is a
x::w::text_param
that's constructible from a plain text string, but also offers the means
of specifying fonts and colors.
inputfieldsandbuttons.C
demonstrates how to use
an alternative create_button() overload that
uses a factory to create the “Ok” button's content:
factory->create_button([] (const x::w::factory &f) { });
This overload takes a single lambda or a callable object
as a parameter. The lambda receives another factory as its sole
argument, and is expected to use that factory to create a single widget. This becomes the contents of the button. Like all widgets they must be show()n in order to
be visible.
The
create_button() that takes a text string
parameter is just a wrapper that uses
create_label() to put the label into
the button, and show() it, like demonstrated
by inputfieldsandbuttons.C.
create_button's optional second parameter
specifies non-default button settings and configurations:
factory->create_button("Ok", { x::w::default_button(), x::w::shortcut{'\n'}, });
This second parameter is a template that takes a variadic list of values, and the simplest approach is to simply use the uniform initialization syntax to construct the parameter object. Multiple values must appear in the following order:
x::w::label_config
This value is only allowed as an option when
create_button()'s first parameter is
a x::w::text_param. This value gets
forwarded to create_label when creating
the new button's label.
x::w::button_config
This setting specifies the button's visual appearance. The default
value for this setting gets returned by
x::w::normal_button().
This results in a regular button, with a normal border.
x::w::default_button()
returns an alternative appearance with a thicker border;
typically for a window's default button that gets activated
by Enter key.
x::w::shortcut
A keyboard shortcut.
There are several ways to activate a button:
Clicking on the button with pointer button 1.
Enter or Space with the input focus in the button.
The keyboard shortcut, with the input focus anywhere in the window.
A keyboard shortcut gets recognized only if the key combination
does not get processed by the field with the current keyboard input
focus.
inputfieldsandbuttons.C
sets shortcuts for all three buttons it creates:
Esc for the “Cancel” button,
ALT-R for the “Reset” button, and
Enter for the “Ok” button, but
the Enter shortcut only works when the keyboard
focus is in the first text input field (or no input field has
keyboard focus).
When the current keyboard input focus is in the second text input field, Enter inserts a new row. When it's in any button, Enter activates that button. A keyboard shortcut takes effect only if its key does not result in any other action.