hello,

in line 25 you install a new ball.

Now you want to give it a start position Y, let's say 150:

1.   balls.add(new Ball(10, 150, ballWidth));

stopPosition in method move.

In the constructor line 36 you have to insert tempStopPosition and in line 25 as well and so on.

Remove all usage of gravity.

To send an existing  ball to a new position you need a new method moveTo which sets a new stopPosition.

Anyway, in mouseClicked (better use mouseReleased) you need to count the number of mouseReleased
and with a switch-command decide what number you're at and what to do there.

It's a steep path, I agree.


Greetings, Chrisir   

Hey Chrisir, thanks for the reply. Indeed I have tried your solution, but it somehow can't pass the values to the class? No idea why!!! 

In your constructor, you have to assign the passed paramaters to the fields of the class, not the other way.

1. beginPos = tempBegin;
2. stopPos = tempStop;

Checked most of the issues, however problem remains. I still can't make my Arrraylist objects to move independently, and also to remove the firstly created (and shift objects, i.e. first is deleted, second goes to the first place, and so on). Something's wrong with my Arraylist, but what!!!!?

Hey,

there are several things.
– "speed" is never initialized, so it is 0. You should assign a value higher than 0 to make have an effect.
– You are increasing "y" within "moveThis()", but you use "beginPos" in "display()".
– you ignored what i wrote about the mouseReleased()-function. You have to change the stop-position for all Balls, currently you only calculate the stopPosition for the new ball you create.

Benja, thanks for the comments. 

do you want the rects next to each other like a few escalators next to each other (width of each maybe 30) or
all with the width of the whole window (overlapping)?

when so you want to delete them?
When at the end of the screen?

Then it's

1.     if (ball.y+ball.h > height) {
2.       balls.remove(i);
3.     }

What is mouseVar supposed to do?

greetings!

Hi! I was just replying with this solution!

yeah, nice to hear.

Here is my version.

Greetings!   

1. ArrayList<Ball> balls;
2. int xPos = 10;
3. int yPos = 0;
4. int rectWidth = 10; //  width-20;
5. int rectHeight = 20 ;  // 120;
6. int beginPosition = 0;
7. int stopPosition = 150;
8. int mouseVar;
9. float rCol, gCol, bCol;
10. void setup() {
11.   size(400, 800);
12.   frameRate(10);
13.   smooth();
14.   noStroke();
15.   balls = new ArrayList();
16. } // func
17. void draw() {
18.   background(255);
19.   // for-loop
20.   for (int i = balls.size()-1; i >= 0; i--) {
21.     Ball ball = balls.get(i);
22.     ball.moveThis();
23.     ball.display();
24.   } // for
25.   // a new for-loop to delete balls
26.   // (it is better to have 2 separate for-loops)
27.   for (int i = balls.size()-1; i >= 0; i--) {
28.     Ball ball = balls.get(i);
29.     if (ball.y+ball.h > height) {
30.       balls.remove(i);
31.     } // if
32.   } // for
33.   println(balls.size());
34. } // func
35. void mouseReleased() {
36.   for (int i = 0; i < balls.size(); i++) {
37.     Ball ball = balls.get(i);
38.     ball.stopPos+=150;
39.   } // for
40.   yPos = mouseVar * 150;
41.   mouseVar = (mouseVar+1) % 5;
42.   mouseVar++;
43.   rCol = random(255);
44.   gCol = random(255);
45.   bCol = random(255);
46.   balls.add(new Ball(xPos*mouseVar, yPos,
47.   rectWidth, rectHeight,
48.   beginPosition, stopPosition,
49.   rCol, gCol, bCol));
50. } // func
51. // ==================================================
52. class Ball { 
53.   // pos
54.   float x;
55.   float y;
56.   // size
57.   float w;
58.   float h;
59.   // movement
60.   float beginPos;
61.   float stopPos;
62.   float speed = 5;
63.   // color // or use color
64.   float r, g, b;
65.   Ball(float tempX, float tempY,
66.   float tempW, float tempH,
67.   float tempBegin, float tempStop,
68.   float tempR, float tempG, float tempB) {
69.     x = tempX;
70.     y = tempY;
71.     w = tempW;
72.     h = tempH;
73.     beginPos = tempBegin;
74.     stopPos = tempStop;
75.     r = tempR;
76.     g = tempG;
77.     b = tempB;
78.   }
79.   void moveThis() {
80.     y = y + speed;
81.     if (y > stopPos) {
82.       y = stopPos;
83.     }
84.   }
85.   void display() {
86.     fill(r, g, b);
87.     rect(x, y, w, h);
88.   }
89.   //
90. } // class
91. //

a few remarks to your code:

• you don't need to pass r and g and b separately to your class. Just use the datatype color instead. So you need the to change the vars, the constructor and method display() in your class. In line 44 say   balls.add(new Ball(xPos, yPos, rectWidth, rectHeight, beginPosition, stopPosition, color (rCol, gCol, bCol) ));
  
• You can tell the arraylist which objects it has (line 1 ArrayList<Ball> balls;), then you don't have to cast the type when getting one object from it. It's then Ball ball = balls.get(i); instead of  Ball ball = (Ball) balls.get(i);
• in display() with the line rect(0, y, width, 120); you don't use most of the properties of the class. Better: rect(x, y, w, h);

Glad you got it working!

greetings, Chrisir  

Check out this old thread