Object data-type

Programming Questions

paul.stro..

in Programming Questions • 1 year ago

Hi everyone

I am using a custom library for some hardware prototypes and am running into an issue which I cant resolve.

One of the functions provided by the library is getDULData(); which returns Object[] as data-type. What I am expecting is an array of integers. However using int() gives me an error, as the int() function does not except the Object datatype.

The library comes with an example, which sadly confuses me even more, and throws an error.

it initiates the veriable "res" like this:

Integer[] res=null;

and within draw then assigns the Object[] to it

res=dul.getDULData();

When I run the code it says cannot convert Object[] to Integer[]

Here is the complete code
import processing.serial.*;
import dulRadio.*;
import processing.opengl.*;
import de.looksgood.ani.*;

DULRadio dul;
Integer[] res=null;
PGraphics pg;
String[] texts=new String[14];
void setup() {
frameRate(25);
size(screen.width, screen.height);
pg=createGraphics(screen.width, screen.height,OPENGL);
//Replace "COM79" with the COM port you inserted the USB stick into
dul=new DULRadio(this, "COM79", 115200, 13);
Ani.init(this);
}
void draw() {
pg.beginDraw();
pg.background(255);
res=dul.getDULData();
if (res!=null && res.length==4) {
float m=map(res[1], -255, 255, 0.5, 1.5);
float m2=map(res[2], -255, 255, 0.5, 1.5);
float m3=map(res[3], -255, 255, 0.5, 1.5);
pg.translate(width/2, height/2);
pg.pushMatrix();
pg.rotateZ(PI*m);
pg.rotateX(PI*m2);
pg.rotateY(PI*m3);
pg.box(100);
pg.popMatrix();
}
pg.endDraw();
}

More infos to what this is about can be found here: http://www.digitalurbanliving.dk/news/news/dul-radio.php

Its actually pretty cool :-)

If anyone could give me some tip on how to sort out my data-issues, I would be really grateful

Thanks

Replies(10)

paul.stro..

Re: Object data-type

1 year ago

if I simply do this within draw:

println(dul.getDULData());

it prints out the following:

[0] 3

[1] 15

[2] -18

[3] -273

[4] ""

Which is exactly what I expect from it. I just dont know how to actually use these values within processing, becouse I dont know how to get them into any other datatype.

tfguy44

Re: Object data-type

1 year ago

Try:

Object[] objData = dul.getDULData();
int[] intData;
for( int i =0, i<objData.length; i++){
intData.append( int( objData[i] ) );
}

paul.stro..

Re: Object data-type

1 year ago

still same problem:

processing does not like this:

intData.append( int( objData[i] ) );

says that

The method parseInt(boolean) in the type PApplet is not applicable for the arguments (Object)

paul.stro..

Re: Object data-type

1 year ago

intData.append( objData[i] );

gets

Cannot invoke append(Object) on the array type int[]

other curios thing:

while

println(dul.getDULData());

returns this:

[0] 3

[1] 17

[2] -19

[3] -272

[4] "

print(dul.getDULData());

returns the following:

[Ljava.lang.Object;@943dc4

tfguy44

Re: Object data-type

1 year ago

How about the rather-direct:

int[] intData = dul.getDULData();

Also, println() tries to treat them as strings. What do you get if you try:

Object[] objData = dul.getDULData();
String strOne = "" + objData[0];
println( strOne );

tfguy44

Re: Re: Object data-type

1 year ago

Whoa, someone gave me a best answer award for this. Does that mean I hit on a solution?

paul.stro..

Re: Object data-type

1 year ago

I've tried the rather direct. However, your second suggestion works:

This here does the trick:

Object[] objData = dul.getDULData();
if(objData !=null ){
String strOne = "" + objData[1];
x = int(strOne);
}
println(x);

Thank you so much.

PhiLho

Re: Object data-type

1 year ago

A bit convoluted to use a string as interim...
A more regular way is to cast the objects to Integer:

Object[] getDULData()
{
return new Object[] { 5, 10, 15, 20 };
}
void setup()
{
println(getDULData());
Object[] objects = getDULData();
int[] values = new int[objects.length];
for (int i = 0; i < values.length; i++)
{
values[i] = (Integer) objects[i];
}
println(values);
}

paul.stro..

Re: Object data-type

1 year ago

Thanks Phi.lho.

Your solution *is* more elegent (and I think this is what the actual author of the code meant to be doing...)

btw. I have never seen this type of syntax:

(Integer) objects[i];

is this some generall java thing, which I know nothing about or is this some specific pecularity in regards to type casting?

PhiLho

Re: Object data-type

1 year ago

It is a Java thing which borrowed the syntax & concept from C. And indeed, that's type casting (ie. it is called a "cast").
It doesn't do magic (ie. it won't convert a String to an Integer), but it can transform a generic type (here Object, that's the most generic you can get) to a more specific type (Integer).

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