day3，子弹发射位置改至坦克中间

tankWar/src/com/mashibing/tank/Bullet.java

@@ -9,8 +9,8 @@ import java.awt.*;
  */
 public class Bullet {
     private static final int SPEED = 10;
-    private static final int WIDTH = 20;
+    public static int WIDTH = ResourceImageRead.BULLET_DOWN.getWidth();
-    private static final int HEIGHT = 20;
+    public static int HEIGHT = ResourceImageRead.BULLET_DOWN.getHeight();
 
     private int x;
     private int y;

tankWar/src/com/mashibing/tank/Tank.java

@@ -9,6 +9,9 @@ import java.awt.*;
  */
 public class Tank {
     private static final int SPEED = 5;
+    public static int WIDTH = ResourceImageRead.TANK_DOWN.getWidth();
+    public static int HEIGHT = ResourceImageRead.TANK_DOWN.getHeight();
+
     private int x;
     private int y;
     private Direction direction;
@@ -79,8 +82,11 @@ public class Tank {
      * 解决：坦克对象要持有FrameTank对象的引用
      */
     public void fire() {
+        int bulletX = this.x + Tank.WIDTH / 2 - Bullet.WIDTH / 2;
+        int bulletY = this.y + Tank.HEIGHT / 2 - Bullet.HEIGHT / 2;
+
         // 将子弹加入子弹集合
-        frameTank.bulletList.add(new Bullet(this.x, this.y, this.direction, this.frameTank));
+        frameTank.bulletList.add(new Bullet(bulletX, bulletY, this.direction, this.frameTank));
     }
 
     public Direction getDirection() {