Key triggeres animation

Question

So I'm working on my first java based game to work on my basic gui skills. I'm want it so that when the up key is pushed a shot is fired (just a circle). I'm not sure how to approach it though, whether to use graphics2d to create a fillarc and make it visible when the button is pushed, or have it created when the up key is pushed. But the problem I find with the latter is that I would have to make an inner class in the paintcomponent and it needs to be in the default constructer. So i was wondering if anyone could help me with this problem?

Answer 1

Okay so I figured a way to do a key triggered animation. I used space instead of up and had it change a boolean shot to true(when pressed) and while shot is true, the x and y coordinates of the shot (beginning at the end of the gun) are either incremented or decremented and added to the x and y of the fillarc() method in order to animate the shot in a certain direction, but now when I press space the game freezes completely. I can't figure it out, can anyone tell me why this is happening?
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
public class Book_Game extends JFrame{
    Home_Base home = new Home_Base();
    public Book_Game(){
        add(home);
        home.setFocusable(true);
    public static void main(String[] args){
        Book_Game frame = new Book_Game();
        frame.setSize(600, 500);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    class Home_Base extends JPanel{
        //Gun & Base -> values obtained through print out of getHeight() and getWidth() methods
       private int BaseH = (int)(464*.85);
       private int radius = (int)(464/8);
       private int GunY = 464;
       private int GunXcenter = (int)(584/2);
       private int GunX = GunXcenter - radius;
       private int GunYlength = GunY - 100;
       private int GunXlength = 584 + (int)(radius*1.6);
       private int angle = 0;
       //Random Object for a random integer
       Random r = new Random();
      //Enemy fire coordinates in random positions above Base's gun
       private int EnemyFireX = r.nextInt(584);
       private int EnemyFireY = r.nextInt(GunY - 150);
       private boolean shot = false;
       private int shotX = 0;
       private int shotY = 0;
       //Gun angle X & Y for shot direction
       private int GangleX = 0;
       private int GangleY = 0;
       public Home_Base(){
            javax.swing.Timer timer = new javax.swing.Timer(500, new TimerListener());
            timer.start();
            addKeyListener(new KeyAdapter(){
                    public void keyPressed(KeyEvent e){
                        switch(e.getKeyCode()){
                            case KeyEvent.VK_RIGHT : angle += 5; break;
                            case KeyEvent.VK_LEFT  : angle -= 5; break;
                            case KeyEvent.VK_SPACE : shot = true;
                        repaint(GunXcenter - 100, GunY - 100, 200, 200);
        protected void paintComponent(Graphics g){
            super.paintComponent(g); // clear the screen
            Graphics2D g2 = (Graphics2D)g;
            //Gun Base
            g2.fillArc(GunX, GunY - radius, radius * 2, radius * 2, 0, 180);
            //Buildings
            g2.fillRect(0, BaseH, radius/2, GunY - BaseH);
            //Fire
            int EnemyFire = (int)(Math.min(getWidth(), getHeight()) * 0.04);
            //Fill in the Enemies Fire
            if((EnemyFireY+(2*EnemyFire))<BaseH){
                EnemyFireY += 10;
            }else if((EnemyFireY+(2*EnemyFire))>=BaseH){
                EnemyFireX = r.nextInt(584);
                EnemyFireY = r.nextInt(GunY - 150);
            g2.fillArc(EnemyFireX, EnemyFireY, 2*EnemyFire, 2*EnemyFire, 0, 360);
            //shot
            //x & y locations of the tip of the gun
            int EndofGunXcenter = GunXcenter - (EnemyFire/2);
            int EndofGunYcenter = GunYlength - (EnemyFire/2);
            while(shot != false){
                GangleY -= angle;
                if(angle < 0){
                    GangleX -= angle;
                }else
                if(angle > 0){
                    GangleX += angle;
                g2.fillArc(EndofGunXcenter + GangleX , EndofGunYcenter + GangleY, EnemyFire, EnemyFire, 0, 360);
            //gun
            AffineTransform af = new AffineTransform();
            af.translate(GunXcenter, getSize().height );
            af.rotate(Math.toRadians(angle));
            g2.transform(af);
            g2.drawLine(0, 0, 0,  -100 );
            class TimerListener implements ActionListener{
                public void actionPerformed(ActionEvent e){
                    repaint();
}