Trigger button to change the small circle color on panel panels

Importjavax.swing.*;Importjava.awt.event.*;Importjava.awt.*; Public classTouchacolImplementsactionlistener{JFrame frame;  Public Static voidmain (String [] args) {Touchacol game=NewTouchacol ();    Game.go (); }         Public voidGo () {frame=NewJFrame (); JButton Button=NewJButton ("Can You Touch me?")); Button.addactionlistener ( This); Panel Apanel=NewPanel ();        Frame.setdefaultcloseoperation (Jframe.exit_on_close);        Frame.getcontentpane (). Add (Borderlayout.south,button);                Frame.getcontentpane (). Add (Borderlayout.center,apanel); Frame.setsize (300, 300); Frame.setvisible (true); }         Public voidactionperformed (ActionEvent event) {frame.repaint (); }}

View class Touchacol

Query the Java API documentation:

ActionEvent class from Java.awt.event

Jframe,jbutton class from Javax.swing

Interface Actiolistener from Java.awt.event

BorderLayout class from java.awt usage: Borderlayout.south/center ... See documentation

Importjavax.swing.*;Importjava.awt.*; Public classPanelextendsjpanel{ Public voidpaintcomponent (Graphics g) {intRed = (int) (Math.random () * 255); intGreen = (int) (Math.random () * 255); intBlue = (int) (Math.random () * 255); Color MyColor=NewColor (Red,green,blue);        G.setcolor (MyColor); G.filloval (70,70, 100, 100); }}

View class Panel

Let the panel inherit JPanel, and the Paintcomponent (Graphics g) method that overrides it can draw as you want

Overall thought:

Build a class Touchacol

1 JFrame, Panel (inherited JPanel) and button objects are built separately

Then put the object of the latter two on the JFrame object, set the listener of the button to the object of Touchacol (the object is ActionListener)

So the actionperformed (ActionEvent e) method in interface ActionListener is implemented as an event-handling method in the class of the object (E is the button being pressed)

Deliberately set the frame as an instance variable.

Trigger button to change the small circle color on panel panels