Setfocusable method or focusing components Java

I encountered this Code:

public class Board extends JPanel implements ActionListener{


    public Board(){

    setFocusable(true); 

    }

}

If I set setfocusable to true, what exactly does this method do to JPanel objects? What is the concept of focusing on components?

Based on Java API, this method is located in component class (super class of JPanel) The method description states that "set the focusable state of this component to the specified value. This value will override the default focusable state of the component." To me, this description sounds too technical and advanced jargon (they just finished their java course in the summer) Sometimes I don't think these method descriptions are written for all people with different levels of java knowledge Can anyone explain the method description in non-professional terms?

Solution

The focusable flag indicates whether the component can obtain focus on request By default, the JPanel component is focusable, so nothing changes when you set it to true

Components that cannot focus cannot get focus

An example

Suppose you have implemented a dialog box with multiple text fields, and you want the user to enter some text When the user starts typing, a text field needs to have the focus of the application: it will be the field that receives keyboard input

When you implement focus traversal (a convenient way for users to jump from one text field to the next, for example, by using tab buttons), users can "jump" to the next text field The application will try to get the focus of the next field in preparation for receiving text When the next field is not focusable, the request is rejected and the next field is tested For example, you don't want a tag to get focus because you can't enter text in it

By default, in the component class, the focusable flag is set to true When constructing an object derived from the component class (for example, when constructing a JPanel), the constructor of the component class is called and the default focusable flag is set to true

Derived classes that want to override this default can call the method setfocusable to change the default, as you did in the example

Please note that setfocusable itself does not set focus, it only provides the function of obtaining focus