Passing variable from another file and then use variable within to another method within same class

Question

I am trying to call a variable from another class in another to the second java file

public class selectFile {
    public void hdrFile(){
        String hdrName = "directory";
        readImage sendVari = new readImage();

        sendVari.setprintHDR(hdrName);
    }
}

public class readImage {
    private String hdr_dir;

    public static void main(String[] args){
        selectFile call_vari = new selectFile();
        call_vari.hdrFile();
    }

    public void setprintHDR(String hdr_dir){
        this.hdr_dir = hdr_dir;
    }

    public String getprintHDR(){
        return hdr_dir;
    }

    public void anotherMethod(){
        System.out.println(getprintHDR());
    }
}

I am doing this because I want to use "anotherMethod" Method in second in the third file, but when I am testing in the second java file by printing it to the terminal "anotherMethod" cannot print any hdr_dir even I return hdr_dir. But if I check "setprintHDR" by printing it to the command everything seem fine, it returns "directory"

public class Main {
    public static void main(String[] args){
        readImage call_vari = new readImage();
        call_vari.anotherMethod();
    }
}

yes, I call it in another file too, but for now I am just testing it — Beam291, Jan 29 '22 at 04:44
in the code that you have shared, where is the anotherFile from where you are calling this method? — Gurkirat Singh Guliani, Jan 29 '22 at 04:45
so your question is when you run the main class, hdr_dir comes as null, right ? — Gurkirat Singh Guliani, Jan 29 '22 at 04:57
yes, it return nothing, the hdr_dir only come out in method getprintHDR, but not in other methods — Beam291, Jan 29 '22 at 05:00
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/241509/discussion-between-gurkirat-singh-guliani-and-beam291). — Gurkirat Singh Guliani, Jan 29 '22 at 05:03

score 1 · Accepted Answer · answered Jan 29 '22 at 05:21

Since you want to use the updated value in another object( basically trying to share the value between multiple objects), you should keep your variable hdr_dir as static. Static vs Instance Variables: Difference?

You were currently using the variable as instance one due to which if one object updates the value, it will remain specific to that object only. For your main class,

public class Main {
    
//    private String hdr_dir;

    public static void main(String[] args){
        int res = 0; 
         selectFile call_var = new selectFile();
         call_var.hdrFile();
        readImage call_vari = new readImage();
//        call_var.anotherMethod();
//        call_vari.setprintHDR("printHDR");
        call_vari.anotherMethod();
    }
}

and the output is

value of hdr_dir is passed is  -------directory // doing some console logging 
value of hdr_dir assigned is  -------directory
directory

Passing variable from another file and then use variable within to another method within same class

1 Answers1