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ArrayList question (Read 627 times)

GiveMeMore

ArrayList question
Apr 23^rd, 2009, 8:31am

I'm newbie. When I try to run this sketch, it gave me "Cannot convert from Object to int" on the line p = pitches.get(i);
Also, I wonder how to declare and initialize an ArrayList in a class. I wonder if I actually did it the right way. Many thanks in advance for your help.
Quote:

class ChanLite
{
    int x;
    int y;
    ArrayList pitches;

    ChanLite(int ix, int iy) {
      x = ix;
      y = iy;
      pitches = new ArrayList(5);
    }

  void display(int pit, int vel) {
        int tr, tg, tb, p = 0;
        pitches.add(pit);
        for (int i = pitches.size()-1; i >=0; i--) {
          p = pitches.get(i);
          tr = tr + red(c[p%12]);
          tg = tg + green(c[(int)pitches.get(i)%12]);
          tb = tb + blue(c[(int)pitches.get(i)%12]);
        }
        fill(tr*vel/128/pitches.size(), tg*vel/128/pitches.size(), tb*vel/128/pitches.size());
        rect(x, y, 20, 20);
  }

  void remove(int pit) {
    // pop
        int tr, tg, tb = 0;
        pitches.add(pit);
        for (int i = pitches.size()-1; i >=0; i--) {
          if (pitches.get(i) == pit) {pitches.remove(i);} else {
          tr = tr + red(c[pit%12]);
          tg = tg + green(c[pit%12]);
          tb = tb + blue(c[pit%12]);}
        }
        fill(tr*vel/128/pitches.size(), tg*vel/128/pitches.size(), tb*vel/128/pitches.size());
        rect(x, y, 20, 20);
  }
}

NoahBuddy

Re: ArrayList question
Reply #1 - Apr 23^rd, 2009, 8:39am

Try casting to Integer rather than int.

An Integer is an object (so it can be cast to another object) while an int is a primitive (just a number).

As for the initialization, it is fine (probably best) as it is; in the constructor.

If you initialize it as
ArrayList pitches = new ArrayList(5);

then all of your ChanLite's would share the same 'pitches'.

GiveMeMore

Re: ArrayList question
Reply #2 - Apr 23^rd, 2009, 9:00am

Thanks, NoahBuddy! (Integer) is it.
However, now I get "cannot cast from float to integer" error. (The c is declared as color[] c; and initialized elsewhere. This is the first time I tried putting this class in a separate tab/file -- do I need to declare it here too?)

for (int i = pitches.size()-1; i >=0; i--) {
p = (Integer) pitches.get(i);
tr = tr + red(c[p%12]);
tg = tg + green(c[p%12]);
tb = tb + blue(c[p%12]);
}

NoahBuddy Ex Member	Re: ArrayList question Reply #3 - Apr 23^rd, 2009, 9:21am Ah, that is because red(), blue(), and green() return a float. Your t* variables are int's. :]

GiveMeMore YaBB Newbies Offline Posts: 18	Re: ArrayList question Reply #4 - Apr 23^rd, 2009, 9:48am Thanks again, NoahBuddy! I discovered it right after posting too.

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