[A5] Multiple User Key Input

no-reply@allegro.cc (sa1k01) — Mon, 14 Nov 2011 20:39:12 +0000

Hi @ all,

i have a question regarding the user key input. Say i have a options dialog with some options like resolution and several key settings for the player.

i know, that i can store a single user input with:

al_ustr_append_chr(ALLEGRO_USTR, event.keyboard.unichar);

but how does this work for multiple input fields? Is there a tutorial for this kind of problem? ^^

greetings
sa1k01

no-reply@allegro.cc (Edgar Reynaldo) — Mon, 14 Nov 2011 22:23:56 +0000

You'll have to set a focus variable when the user clicks on a field. Then only accept input when that field has focus.

no-reply@allegro.cc (sa1k01) — Tue, 15 Nov 2011 14:37:10 +0000

thx for the reply.

mh ok. then i should just wait for an mouse click event and save the x and y position of the label, right?

i will give it a try and let you know if this works.

kind regards
sa1k01

no-reply@allegro.cc (Edgar Reynaldo) — Tue, 15 Nov 2011 22:10:01 +0000

If you're using a struct/class to store your input field object, then just use a pointer to the active object, or store a flag in the class :

#SelectExpand
  1class InputField {
  2private :
 int x,y,w,h;
 string text;
 int caretx;
 bool hasfocus;
  7public :
 bool CheckInput(ALLEGRO_EVENT ev) {
    tookfocus = false;
    if (hasfocus) {
       // check for unicode key char events here
    }
    else {
       // something else
       if (ev.type == ALLEGRO_EVENT_MOUSE_DOWN) {
          tookfocus = Click(ev.mouse.x , ev.mouse.y);
       }
    }
    return tookfocus;
 }
 21
 void SetFocus(bool focus) {hasfocus = focus;}
 23}

#SelectExpand
  1
  2InputField in1,in2,in3;
  3InputField* infield[3] = {&in1 , &in2 , &in3};
  4
  5InputField* infocus = 0;
  6
  7//...
  8   ALLEGRO_EVENT ev;
  9   al_wait_for_event(event_queue , &ev);
 10   for (int i = 0 ; i < 3 ; ++i) {
 11      if (infield[i]->CheckInput(ev)) {
 12         infocus = infield[i];
 13         for (int j = 0 ; j < 3 ; ++j) {
 14            infield[i]->SetFocus(infield[i] == infocus);
 15         }
 16      }
 17   }