java - Set Progressbar from another class -

i'm trying set progressbar class failed. progressbar class upload.

jprogressbar progressbar = new jprogressbar(); progressbar.setbounds(91, 134, 284, 17); frame.getcontentpane().add(progressbar); 

i have class called read. in class have loop needs read file, want set progress iterator i class. know have set minimum , maxium this:

progressbar.setminimum(0); progressbar.setmaximum(numrows); 

and value:

progressbar.setvalue(newvalue); 

how can set value progressbar keeps updating value of i?

first of all, reader class must have reference component (jprogressbar) in question. understand solved.

after that, reading file recommend use class extending javax.swing.swingworker. pattern allows work in background (may heavy operations reading big files) without affecting awt thread, gui won't affected. so, reader should extend javax.swing.swingworker.

as brief resume, provides method called doinbackground should implement 'heavy' operation , method called process received data chunks , add own calculations progress.

the process method executed in awt, can update ui component @ method (so point update progress bar)

please, refer link more information.