Java-我需要在main方法中使用变量boolean，在外部但在同一类中初始化

Question

The boolean has to be outside the main method so other methods can manipulate it. I've searched everywhere and cannot find a suitable answer because all I stumble upon are solutions for booleans as methods. It has to be a simple boolean and it cannot be static. Don't have much time, so any help would be great. Thanks.

public class myClass {

   private int[][] holdsStuff;
   private boolean isNeeded;

   public setFalse (){
   }

   public setTrue () {
   }

   public static void main(String[] args) {
      //call methods to change isNeeded
      //require isNeeded to prevent invalid changes being made to holdsStuff
   }
}

Answer 1

If class member isNeeded is not static, then it must belong to an instance of myclass , you can create a new instance and manipulate this instance:

public class myClass {

    private int[][] holdsStuff;
    private boolean isNeeded;

    public void setFalse (){
        isNeeded = false;
    }

    public void setTrue () {
        isNeeded = true;
    }

    public static void main(String[] args) {
        myClass mc = new myClass();
        myClass.setFalse();

    }
}

Answer 2

public class myClass {

       private int[][] holdsStuff;
       private boolean isNeeded;

       public void setFalse (){
       isNeeded =false;
       }

       public void setTrue () {
        isNeeded = true;
       }

       public static void main(String[] args) {

           myClass myclass = new myClass();
           myclass.setFalse();
           myclass.setTrue();
          //call methods to change isNeeded
          //require isNeeded to prevent invalid changes being made to holdsStuff
       }
    }

Answer 3

since main is static either use static keyward or make an instance of the same class. use static key the following:

public class myClass {

   private int[][] holdsStuff; // make this static if you are also this inside main
   private static boolean isNeeded;

   public static setFalse (){
   }

   public static setTrue () {
   }

   public static void main(String[] args) {
      //call methods to change isNeeded
      //require isNeeded to prevent invalid changes being made to holdsStuff
   }
}

Answer 4

You want to use isNeeded in other methods and in main method which is static and static methods just deal with static data read this . so what you want to do is make instance of this class to call isNeeded in main method

 public static void main(String[] args) {
       myClass myclass = new myClass();          
       boolean isNeeded = myclass.isNeeded;
   }