I am using Gtkmm 3+ and What I am trying to do is have the text buffer have the constant string "> " even if the user tries to delete it. In addition when the user pressed return it will automatically be there again. Basically have a constant string like a terminal does.
The only way I can think about about accomplishing this would be to connect to the delete and backspace signals so the user cannot delete the string. But, is there a better way?
so far this is the only way I can think of:
//in constructor
txt_view_i_.signal_event().connect(sigc::mem_fun(*this, &MainWindow::inputEvent));
//function
bool MainWindow::inputEvent(GdkEvent* event)
{
if((event->key.keyval == GDK_KEY_BackSpace || event->key.keyval == GDK_KEY_Delete) && buffer_input_->get_char_count() < 3)
return true;
return false;
}
But doesn't work perfectly, because if you type in more then 3 characters then go to the beginning of the line you can delete the constant string.
Another way I just thought about was to add a label to the TextView widget. I did that but, the user could still delete it. Here is the code for that:
Gtk::TextBuffer::iterator it = buffer_input_->get_iter_at_line(1);
Glib::RefPtr<Gtk::TextChildAnchor> refAnchor = buffer_input_->create_child_anchor(it);
Gtk::Label* lbl = Gtk::manage(new Gtk::Label("> "));
txt_view_i_.add_child_at_anchor(*lbl, refAnchor);
This is very similar, but not quite identical, to the question I answered here: You can create a GtkTextTag that makes its contents uneditable, and apply it from the beginning of the buffer up to and including the "> " prompt.
Then when you receive input, append your output to the buffer and then append a new prompt on the next line, and re-apply the tag to make the whole thing uneditable.
The links in the linked answer show some C code where this is done, even including a prompt. It's not Gtkmm or C++, but it should serve as an illustration.