我可以在主要方法或任何方法中添加ActionListener（）吗？

Question

public void Message() {
@Override
public void actionPerformed(ActionEvent e) {
    JOptionPane.showMessageDialog(null, "Hello it is working");
}

}

//Message() is a method inside a class.

Answer 1

All methods must be declared inside a class separately. In simple terms, methods are something the object of a certain class can do, and defining them inside another method does not make sense. So in your case,

public void Message (){

}
@Override
public void actionPerformed(ActionEvent e){
    JOptionPane.showMessageDialog(null, "Hello it is working");
}

Edit: This post is worth a read. I have no knowledge about lambda expressions, but it could be what you're looking for :) Does Java support inner / local / sub methods?

Answer 2

In Java, nested methods are not allowed!

In order to override actionPerformed method, you need to implement the ActionListener interface.

Answer 3

No. We cannot create nested methods in java. Try reading about actionlisteners . :)

Answer 4

Since Java 8 methods can be nested using lambdas. Can methods in java be nested[...]? No, that's not possible.

The closest thing you can get is:

class Name {
    void methodOne() {
        class InnerClass {
           void methodTwo() {
           }
         }
     }
 }

That is, a second method defined in a inner class defined in a method.

You can declare the method static inside the inner class, so you do not have to call new