How to write to Preferences.txt

d_h_benson

How to write to Preferences.txt

in Library and Tool Development • 3 years ago

Hi,

Can anyone advise me on how to write new settings into Preferences.txt? A Tool I'm working on needs to remember a variable from one launch to the next.

I've tried using the following code to append a line to the preferences file:

File prefFile = Base.getSettingsFile( "Preferences.txt" );

PrintWriter prefWriter = null ;

try {

prefWriter = new PrintWriter( new FileWriter(prefFile, true ));

prefWriter.println( "newSetting = value" );

prefWriter.close();

} catch (IOException e) {

}

This works temporarily. When I view preferences.txt immediately after this code executes my new Setting shows up. Once I close the Processing app, though, my new Setting is erased from the file.

Am I doing something wrong? Is there some other function I should be using to add to Settings?

Or am I taking the entirely wrong approach?

Thanks in advance,

Replies(4)

PhiLho

Re: How to write to Preferences.txt

3 years ago

I searched preferences.txt (no capital, this is important for other platforms than Windows) in the app section of the Procesing code, and found out that the Preferences class is used to manipulate the settings.
It is better to change the live settings since, as you found out, they are saved automatically when the PDE is closed, erasing whatever you could have changed before.
You can use Preferences.set(), Preferences.setBoolean(), Preferences.setInteger(), Preferences.setColor(), to set strings or other kinds of values (first parameter: name, second one: value).

kevin.bjo..

Re: How to write to Preferences.txt

3 years ago

Are you sure you want to save this in the actual prefs file of Processing itself, rather than a file in the project's data dir?

(This does make a relatively painless way to save data BETWEEN sketches...)

KB, Trion Worlds

PhiLho

Re: Re: How to write to Preferences.txt

3 years ago

This is to make a PDE tool. So I supposed the data to save might be independent of the current project.

d_h_benson

Re: How to write to Preferences.txt

3 years ago

Phi.lo, thanks for yet another helpful response. Calling Preference.set() worked perfectly.

KB, you're right that saving to the data directory is another potential solution. As Phi.lo suggests, though, I'm interested in saving a setting that applies to all the projects of a particular user, not just a single project, so adding to Preferences.txt seems more appropriate.

Thanks again to you both.

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