Question

I’m trying to repaint() from another class. I know one way to do this:

//FromClass.java:
SomeClass whatever = new SomeClass(this);

    //SomeClass.java:
        FromClass f;
        public SomeClass(FromClass from){ //constructor
        f = from;
    }
    //after a long part of code
    f.repaint();

Is there any other way to do this, without any parameters in class constructor?
And sorry for my technical English, still learning.

Answer 1

There are numerous ways to share information between classes. I believe that the method you demonstrated is the most effective. Here are some other options:

• Make SomeClass a subclass of FromClass so that it inherits all of the methods defined in FromClass. Then create an instance of FromClass and call methods on the variable. Your class declaration would look like this:

  class SomeClass extends FromClass {
      ...
      super.repaint();  
      ....
  

• Make FromClass an interface and implement it:

  public interface FromClass {
      void repaint();
  }
  
  class SomeClass implements FromClass {
      repaint();
  

Just some other alternatives. 🙂