Simple ncurses form example with fields that actually behaves like fields

fields_magic.c

/*
 * Simple ncurses form example with fields that actually behaves like fields.
 *
 * How to run:
 *	gcc -Wall -Werror -g -pedantic -o test fields_magic.c -lform -lncurses
 */
#include <ncurses/ncurses.h>
#include <ncurses/form.h>
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>

static FORM *form;
static FIELD *fields[5];
static WINDOW *win_body, *win_form;

/*
 * This is useful because ncurses fill fields blanks with spaces.
 */
static char* trim_whitespaces(char *str)
{
	char *end;

	// trim leading space
	while(isspace(*str))
		str++;

	if(*str == 0) // all spaces?
		return str;

	// trim trailing space
	end = str + strnlen(str, 128) - 1;

	while(end > str && isspace(*end))
		end--;

	// write new null terminator
	*(end+1) = '\0';

	return str;
}

static void driver(int ch)
{
	int i;

	switch (ch) {
		case KEY_F(2):
			// Or the current field buffer won't be sync with what is displayed
			form_driver(form, REQ_NEXT_FIELD);
			form_driver(form, REQ_PREV_FIELD);
			move(LINES-3, 2);

			for (i = 0; fields[i]; i++) {
				printw("%s", trim_whitespaces(field_buffer(fields[i], 0)));

				if (field_opts(fields[i]) & O_ACTIVE)
					printw("\"\t");
				else
					printw(": \"");
			}

			refresh();
			pos_form_cursor(form);
			break;

		case KEY_DOWN:
			form_driver(form, REQ_NEXT_FIELD);
			form_driver(form, REQ_END_LINE);
			break;

		case KEY_UP:
			form_driver(form, REQ_PREV_FIELD);
			form_driver(form, REQ_END_LINE);
			break;

		case KEY_LEFT:
			form_driver(form, REQ_PREV_CHAR);
			break;

		case KEY_RIGHT:
			form_driver(form, REQ_NEXT_CHAR);
			break;

		// Delete the char before cursor
		case KEY_BACKSPACE:
		case 127:
			form_driver(form, REQ_DEL_PREV);
			break;

		// Delete the char under the cursor
		case KEY_DC:
			form_driver(form, REQ_DEL_CHAR);
			break;

		default:
			form_driver(form, ch);
			break;
	}

	wrefresh(win_form);
}

int main()
{
	int ch;

	initscr();
	noecho();
	cbreak();
	keypad(stdscr, TRUE);

	win_body = newwin(24, 80, 0, 0);
	assert(win_body != NULL);
	box(win_body, 0, 0);
	win_form = derwin(win_body, 20, 78, 3, 1);
	assert(win_form != NULL);
	box(win_form, 0, 0);
	mvwprintw(win_body, 1, 2, "Press F1 to quit and F2 to print fields content");
	
	fields[0] = new_field(1, 10, 0, 0, 0, 0);
	fields[1] = new_field(1, 40, 0, 15, 0, 0);
	fields[2] = new_field(1, 10, 2, 0, 0, 0);
	fields[3] = new_field(1, 40, 2, 15, 0, 0);
	fields[4] = NULL;
	assert(fields[0] != NULL && fields[1] != NULL && fields[2] != NULL && fields[3] != NULL);

	set_field_buffer(fields[0], 0, "label1");
	set_field_buffer(fields[1], 0, "val1");
	set_field_buffer(fields[2], 0, "label2");
	set_field_buffer(fields[3], 0, "val2");

	set_field_opts(fields[0], O_VISIBLE | O_PUBLIC | O_AUTOSKIP);
	set_field_opts(fields[1], O_VISIBLE | O_PUBLIC | O_EDIT | O_ACTIVE);
	set_field_opts(fields[2], O_VISIBLE | O_PUBLIC | O_AUTOSKIP);
	set_field_opts(fields[3], O_VISIBLE | O_PUBLIC | O_EDIT | O_ACTIVE);

	set_field_back(fields[1], A_UNDERLINE);
	set_field_back(fields[3], A_UNDERLINE);

	form = new_form(fields);
	assert(form != NULL);
	set_form_win(form, win_form);
	set_form_sub(form, derwin(win_form, 18, 76, 1, 1));
	post_form(form);

	refresh();
	wrefresh(win_body);
	wrefresh(win_form);

	while ((ch = getch()) != KEY_F(1))
		driver(ch);

	unpost_form(form);
	free_form(form);
	free_field(fields[0]);
	free_field(fields[1]);
	free_field(fields[2]);
	free_field(fields[3]);
	delwin(win_form);
	delwin(win_body);
	endwin();

	return 0;
}

If you need help with designing the front end of your form (in particular coordinates) then you can try our form designer utility. It is not fully featured but it can save a lot of time putting in wrong coordinates, building, moving things around, rebuilding etc. ssh [email protected] password is "nc". If you want to know how to use it then head over to https://level2.support?_req=form_designer.

It only does the basics though because the rest need our library (which currently needs to much work to release into the wild and has a bucket load of dependencies).