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Index › Programming Questions & Help › Syntax Questions › Object to int conversation and drawing
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Object to int conversation and drawing (Read 723 times)
skwwwks
Object to int conversation and drawing
Dec 23rd, 2008, 11:54am  
I have the following Object v : [[0, 0, 4, 4, 4, 4, 4, 4, 0, 0, 0, 4], [0, 0, 0, 4, 4, 4, 4, 4, 6, 2, 2, 3], [0, 4, 4, 4, 4, 4, 4, 4, 6, 2, 2, 2]]

println( v.get(1))  
----
gives [0, 0, 4, 4, 4, 4, 4, 4, 0, 0, 0, 4]

Vector v1 = (Vector) v.get(1);
println(v1.get(5));  
----
gives 4

line (v1.get(0),v1.get(1),v1.get(2),v1.get(3));
----
gives
The method line(float,float,float,float) in the type PApplet is not applicable for the arguments(Object, Object, Object, Object)


Please help me how to draw a line
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sw01
Re: Object to int conversation and drawing
Reply #1 - Dec 23rd, 2008, 1:58pm  
You need to cast it after retrieving from a container.  It's a big pain when generics can't be used.

Pain:

line ((Float)v1.get(0),(Float)v1.get(1),(Float)v1.get(2),(Float)v1.get(3));


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skwwwks
Re: Object to int conversation and drawing
Reply #2 - Dec 23rd, 2008, 5:51pm  
thank you, but it says:

Exception in thread "Animation Thread" java.lang.ClassCastException: java.lang.Integer
at getting_data.setup(getting_data.java:53)
at processing.core.PApplet.handleDraw(PApplet.java:1383)
at processing.core.PApplet.run(PApplet.java:1311)
at java.lang.Thread.run(Thread.java:613)


- really pain
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sw01
Re: Object to int conversation and drawing
Reply #3 - Dec 23rd, 2008, 6:20pm  
Try this instead, then.

Modified pain:

line ((Integer)v1.get(0),(Integer)v1.get(1),(Integer)v1.get(2),(Integer)v1.get(3));
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skwwwks
Re: Object to int conversation and drawing
Reply #4 - Dec 24th, 2008, 6:16am  
This type of pain is much better and works, thank you!
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sw01
Re: Object to int conversation and drawing
Reply #5 - Dec 24th, 2008, 6:28am  
No problem.  

Way to reduce the pain is to have a good way to keep track of what goes into the array.  The problem/confusion was caused because the transformation of primitive (int) to wrapper class (Integer) happened by autoboxing magic.

It's usually better to be clear and explicit in these matters.
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