application with save/open

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rsylv

in General Discussion • Other • 1 year ago

Hi,

After some searching I'm still wondering what the best approach is to make an application in processing able to save some settings in a separate file (eg - video file paths, volume control variables, a project name) which can then be loaded back in once the sketch/application is open. This isn't for a web page but for a stand-alone windows application. Would xml be the right place to look? On a related topic, is it possible to use a webpage to interact with an application that is on the client machine, ie - not an applet on the webpage.

Thanks for any assistance.

Replies(6)

PhiLho

Re: application with save/open

1 year ago

The simplest way in Processing is to use saveStrings() / loadStrings() with your own format (that you can parse back).
XML is probably overkill, unless you have very complex hierarchical settings...
A classical approach in Java is to use properties files, there is a full API to handle them.

I am not sure to understand your last question, but if that's what you meant, you can load a Web page with loadStrings() or new XMLElement().

rsylv

Re: application with save/open

1 year ago

Thanks I didn't realise loadStrings() could be used like this. Apologies for my noobness to programming but when you say you can use 'your own format' can I simply save/load a text file in setup that has a list of values for int variables already included in the sketch? Eg, inside my txt file;

variable1 = 4;

variable2 = 5;

Testing this using the documentation hasn't worked very well so I'm not sure I'm understanding correctly yet.

sansumbre..

Re: application with save/open

1 year ago

The text will come in as Strings. Processing provides useful functions for manipulating strings and converting them to other data types, like float and int.

Your own format is however you decide to save your text. An example is comma-separated, which looks like this:

4,5,6

You could generate that from

String output = str(someVariable) + "," + str(otherVariable) + "," + str(yetAnotherVariable);

If you know what order you saved your variables in (you'd better), you can then reload them from the file. Have a look at the split() function and int() and float() for type conversion.

rsylv

Re: application with save/open

1 year ago

Good explanation, thanks. I've used type conversion before but needed to fill in some gaps on how this would work.

cheers.

PhiLho

Re: application with save/open

1 year ago

Here is a quick, simplistic example:

String props = "H:/Temp/save.txt";

int foo = 42;
float irr = 3.1415926535;

String[] toSave =
{
  "foo=" + str(foo),
  "irr=" + str(irr)
};

println(foo + " " + irr);

saveStrings(props, toSave);

foo = 0;
irr = 0;

println(foo + " " + irr);

String[] restored = loadStrings(props);
for (int i = 0; i < restored.length; i++)
{
  String line = restored[i];
  String[] parts = line.split("=");
  if (parts[0].equals("foo"))
  {
    foo = int(parts[1]);
  }
  else if (parts[0].equals("irr"))
  {
    irr = float(parts[1]);
  }
}

println(foo + " " + irr);

exit();

It is suitable for a small number of variables. For more variables, perhaps using Properties as I wrote, or a serialization library (using reflection to access the variables automatically), can be easier to use.

rsylv

Re: application with save/open

1 year ago

I got a variation of this working, thanks.

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