Adding, deleting and recalling shapes in an arraylist

Programming Questions

epluslike..

Adding, deleting and recalling shapes in an arraylist

in Programming Questions • 1 year ago

Hey there, I'm fairly new to Processing, but I seem to have picked it up quite easily thanks to the posts on the forum :)

I am working on a sketch that lets the user add ellipses by pressing one key, giving them focus by clicking on them, moving them about by clicking and dragging, and removing the focused shape them by pushing another key. It will eventually be used as a user interface for an audio installation I will be running in the next few months.

I can get most of this to work, but the thing I am having trouble with is recalling necessary data associated with each shape such as X/Y data as well as further information that I wish to store.

For example, lets say I have created 4 ellipses on the canvas, when I click on one of them, I would like to be able to recall a list with 6 pieces of info from them - [X(float), Y(float), float, float, float, String] .

The ultimate goal is to be able to save the array into a .txt file and the recall the locations and associated information for each shape on startup so the user can continue working on the project.

So far I have been using two examples of adding/removing shapes, but I am a little confused on the rest. Here is my modified ball class sketch to show you what I mean.

//So here I have an arraylist that is storing the ball data, but I have no idea how to call it up from the array in order to
//put it onscreen.
ArrayList balls;
int ballWidth = 48;
void setup() {
size(500, 500);
smooth();
noStroke();
// Create an empty ArrayList
balls = new ArrayList();
// Start by adding one element
balls.add(new Ball(width/2, 0, ballWidth));
}
void draw() {
background(255);
// With an array, we say balls.length, with an ArrayList, we say balls.size()
// The length of an ArrayList is dynamic
// Notice how we are looping through the ArrayList backwards
// This is because we are deleting elements from the list
for (int i = balls.size()-1; i >= 0; i--) {
// An ArrayList doesn't know what it is storing so we have to cast the object coming out
Ball ball = (Ball) balls.get(i);
ball.display();
/*
if (ball.finished()) {
// Items can be deleted with remove()
balls.remove(i);
}
*/
}
addsource();
}
void addsource () {
if(keyPressed==true){
if (key == 'b' || key == 'n') {
balls.add(new Ball(mouseX, mouseY, ballWidth));
} else {
}
if(key == 'r'){
if(balls.size()>0){
balls.remove(0);
} else {
println("Nothing to delete!");
}
}
}
}
void mousePressed() {
// A new ball object is added to the ArrayList (by default to the end)
balls.add(new Ball(mouseX, mouseY, ballWidth));
}
//Class down here, not all of it is used.
class Ball {
float x;
float y;
float speed;
float gravity;
float w;
float life = 255;
Ball(float tempX, float tempY, float tempW) {
x = tempX;
y = tempY;
w = tempW;
speed = 0;
gravity = 0.1;
}
void move() {
// Add gravity to speed
speed = speed + gravity;
// Add speed to y location
y = y + speed;
// If square reaches the bottom
// Reverse speed
if (y > height) {
// Dampening
speed = speed * -0.8;
y = height;
}
}
boolean finished() {
// Balls fade out
life--;
if (life < 0) {
return true;
} else {
return false;
}
}
void display() {
// Display the circle
fill(0,life);
//stroke(0,life);
ellipse(x,y,w,w);
}
}

I have also had a play with this. I have gotten the shapes to be added at a click of a button, but not to be removed in this case -

http://processing.org/discourse/beta/num_1229481132.html

Thanks guys, I really appreciate your help.

Iyad.

Replies(3)

benja

Re: Adding, deleting and recalling shapes in an arraylist

1 year ago

Hey,

i'm not completly sure, what you want to achieve, maybe i misunderstood the problem.
But to store information on your Ball-objects, you could for example add a function that gives you a String with all your variables.

String infoString(){
String infoString = x+","+y+","+speed+","+gravity+","+w+","+life;
return(infoString);
}

Then just save all the these Strings to a txt file with saveStrings().

String[] strings = new String[balls.size()];
for(int i =0; i<balls.size(); i++){
Ball ball = (Ball)balls.get(i);
strings[i] = ball.infoString();
}
saveStrings("data.txt", strings);

To load this file when you restart the sketch use loadStrings().

Greetings.

epluslike..

Re: Adding, deleting and recalling shapes in an arraylist

1 year ago

Hi, thanks for you reply. Apologies, I have kind of changed what I am trying to do. I am trying to add and remove shapes in an area, and have them named intelligently. If you look at the code below and press any keyboard key to add a shape, you'll see that you can click and drag them where ever you like as well as add more that follow a numerical sequence.

The issue arises when I give focus to an object (by clicking or dragging on it) and right click to delete it. The shape does delete, but unless you delete a shape with the highest number, you cut a huge hole in the arraylist, and it no longer removes them in sequence, in fact, it crashes.

So I am trying to figure out how to update the names of each shape so that all of the shapes with a number higher than the one that has been deleted gets named with a number one lower than the original.

Please run the code below -

import java.util.ArrayList;
ArrayList myQueries;
abstractSearchObject queryBeingDragged;
int dragX;
int dragY;
String QueryChange = "Query";
int removethis = 0;
int shapefocus = 1;
int shapefocus1 = 1;
int removenumber = 0;
int number = 0;
void setup()
{
queryBeingDragged = null;
myQueries = new ArrayList();
size(800, 500);
smooth();
}
void draw()
{
background(0);
for (int i = 0; i < myQueries.size(); i++) {
abstractSearchObject myQuery1 = (abstractSearchObject)myQueries.get(i);
myQuery1.display();
removenumber = myQueries.size();
}
if (keyPressed==true) {
//Adding shapes.
QueryChange = "Query"+myQueries.size();
Hit h1 = new Hit(QueryChange, color(0, 255, 0), width/2.0+100, height/5.0+50, 100, 20);
myQueries.add(h1 );
delay(100);
}
if (mousePressed && (mouseButton == RIGHT)) {
if (myQueries.size()>0) {
//Removing shapes
//Changing the arrays above the one removed to one number below.
//For everything above the one deleted until the end of the array -----
for (int i = shapefocus; i<myQueries.size();i++) {
QueryChange = "Query"+(myQueries.size()-1);
abstractSearchObject myQuery13 = (abstractSearchObject)myQueries.get(i);
println(myQuery13);
myQuery13.update(QueryChange);
//ALL THE SHAPES ABOVE THE ONE THAT HAS JUST BEEN DELETED SHOULD BE RENAMED TO ONE BELOW IT.
}
//Remove the one we don't want
myQueries.remove(shapefocus);
delay(100);
}
}
}
void mousePressed() {
for (int i = 0; i < myQueries.size(); i++) {
abstractSearchObject myQuery1 = (abstractSearchObject)myQueries.get(i);
evaluateQuerySelection(myQuery1);
}
}
void mouseReleased() {
queryBeingDragged = null;
}
void mouseDragged() {
if ( queryBeingDragged != null) {
String tempname = queryBeingDragged.name;
shapefocus = int(tempname.substring(5));
queryBeingDragged.moveByMouseCoord(mouseX, mouseY);
}
}
void evaluateQuerySelection(abstractSearchObject myQuery1) {
if (myQuery1.inQuery(mouseX, mouseY) & queryBeingDragged==null) {
dragX = (int)myQuery1.qx - mouseX;
dragY = (int)myQuery1.qy - mouseY;
queryBeingDragged = myQuery1;
String tempname = queryBeingDragged.name;
shapefocus = int(tempname.substring(5));
}
}
//Classes down here.
abstract class abstractSearchObject {
String name;
color qc;
float qx;
float qy;
int dQx;
int dQy;
abstractSearchObject(String name, color tempQc, float tempQx, float tempQy, int tempdQx, int tempdQy) {
this.name = name;
qc = tempQc;
qx = tempQx;
qy = tempQy;
dQx = tempdQx;
dQy = tempdQy;
}
void display() {
stroke(0);
fill(qc);
rectMode(RADIUS);
rect(qx, qy, dQx, dQy);
fill(0);
text(name, qx, qy);
text(qx + " " + qy, qx-90, qy);
}
boolean inQuery(int x, int y) {
if ((x > qx-dQx) & x < (qx+dQx)) {
if ((y > qy-dQy) & y < (qy+dQy)) {
return true;
}
}
return false;
}
void moveByMouseCoord(int mausX, int mausY) {
this.qx = mausX + dragX;
this.qy = mausY + dragY;
}
void update (String name1) {
name = name1;
println(name1);
}
}
class Query extends abstractSearchObject {
//Hit hit = null;
ArrayList connects = new ArrayList();
Query(String name, color tempQc, float tempQx, float tempQy, int tempdQx, int tempdQy) {
super( name, tempQc, tempQx, tempQy, tempdQx, tempdQy);
}
void display() {
super.display(); // see how I'm calling the parent class's draw routine
}
}
class Hit extends abstractSearchObject {
Hit(String name, color tempQc, float tempQx, float tempQy, int tempdQx, int tempdQy) {
super( name, tempQc, tempQx, tempQy, tempdQx, tempdQy);
}
}

benja

Re: Adding, deleting and recalling shapes in an arraylist

1 year ago

Not really sure what your goal is. But it seems like you are doing some things too complicated.
In my opinion, these Objects should have an ID, that doesn't change, so you can always identify them by their unique ID.

But you could just make a function that renames the Querys according to theit position in the ArrayList, simliar to what you already did:

void updateNames(){
for(int i =0; i< myQueries.size(); i++){
abstractSearchObject query = (abstractSearchObject)myQueries.get(i);
query.name = "Query"+i;
}
}

Just be sure to rename them after you remove an object, otherwise it makes no sense.

And another annotation: If you use a typed ArrayList, you don't have to cast the object tape each time you use it.

ArrayList<abstractSearchObject> myQueries;

abstractSearchObject myQuery1 = myQueries.get(i);

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