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accessing variables from a void method in one file and using it in another

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joshmo

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accessing variables from a void method in one file and using it in another

Apr 4th, 2009

I have two .java files and I want to access a variable of a method in one of the files and use it in another. However, I dont want to call the whole method and I dont want the method to return a value...I'll try to illustrate below

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
[COLOR="Red"]//file_A.java[/COLOR]
class file_A{
//some code 
  void first_method(){
      int variable_a=2; //variable used in this method for several things
  }
}
 
[COLOR="Red"]//file_B.java[/COLOR]
class file_B
{
//some code
  void second_method(){
      System.out.println("var"+variable_a);//ofcourse this does not work but Iam trying to do something like this
  }
}
[COLOR="Red"]//file_A.java[/COLOR]
class file_A{
//some code 
  void first_method(){
      int variable_a=2; //variable used in this method for several things
  }
}

[COLOR="Red"]//file_B.java[/COLOR]
class file_B
{
//some code
  void second_method(){
      System.out.println("var"+variable_a);//ofcourse this does not work but Iam trying to do something like this
  }
}

I hope this helps to explain my problem

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Re: accessing variables from a void method in one file and using it in another

Apr 4th, 2009

You can have the variable be "global". Here are 2 examples:

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
class ClassA {
public int variableA = 0;
 
public ClassA() {
 
}
 
public void method() {
   variableA = 2;
}
}
class ClassA {
public int variableA = 0;

public ClassA() {

}

public void method() {
   variableA = 2;
}
}

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
class ClassB {
public ClassB() {
 
}
 
public void methodB() {
  ClassA clA = new ClassA();
  clA.method();
 
  System.out.println(clA.variableA ):
}
}
class ClassB {
public ClassB() {

}

public void methodB() {
  ClassA clA = new ClassA();
  clA.method();

  System.out.println(clA.variableA ):
}
}

If you have a variable declared in a method you cannot access it from outside that method because it is out of scope. You need to declare it inside the class. If you declare it "private" you will need a "get" method in order to return its value.
Now if you want to access it from another class you will need of course to create an instance of the class: "ClassA" and call the method that changes its value.

But things are different when you declare it static:

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
class ClassA {
public static int variableA = 0;
 
public static void method() {
   variableA = 2;
}
}
class ClassA {
public static int variableA = 0;

public static void method() {
   variableA = 2;
}
}

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
class ClassB {
public ClassB() {
 
}
 
public void methodB() {
  ClassA.method();
 
  System.out.println(ClassA.variableA):
}
}
class ClassB {
public ClassB() {

}

public void methodB() {
  ClassA.method();

  System.out.println(ClassA.variableA):
}
}