没有调用KeyListener

Question

在课堂上，我们的任务是重建游戏太空入侵者。现在我正在努力让我的宇宙飞船穿过底部。我一直在使用调试器，但是当我按下箭头时，我的keyPressed方法没有被调用。

package testprogram;
import java.awt.Color;
import java.awt.Graphics; 
import javax.swing.*;
import java.awt.Point;
import java.awt.Polygon;
import java.awt.event.KeyListener;
import java.awt.event.KeyEvent;
public class TestFrame extends JFrame{
    public TestFrame(){
        setBackground(Color.white);
        Test2 t2 = new Test2();
        this.add(t2);
        t2.repaint();
    }
private class Test2 extends JPanel implements KeyListener {
    int width;
    int height;
    DrawObject object;
    public Test2(){
    setSize(500,500);
    setBackground(Color.black);
    this.width = this.getWidth();
    this.height = this.getHeight();
    object= new DrawObject(getWidth(), getWidth());
    addKeyListener(this);
    }

    @Override
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        object.draw(g);
    }
    @Override
    public void keyPressed(KeyEvent k){
        int key = k.getKeyCode();
        if(key == k.VK_LEFT){//if left arrow is pressed
            object.moveLeft();
            repaint();
        }
        if(key == k.VK_RIGHT){//if right arrow is pressed
            object.moveRight();
            repaint();
        }
    }
    @Override
    public void keyReleased(KeyEvent k){
        //dummy method
    }
    @Override
    public void keyTyped(KeyEvent k){
       //used for launching projectile 
    }
    //used to call draw methods
}
private class DrawObject{
    int pnlWidth;
    int pnlHeight;
    int moveInc =5;

    public DrawObject(int pnlWidth, int pnlHeight){
        this.pnlWidth=pnlWidth;
        this.pnlHeight=pnlHeight;
    }
    public void draw(Graphics g){
        Point loc = new Point();
        //bottom right point
        loc.x=pnlWidth;
        loc.y=pnlHeight;
        Polygon triangle = new Polygon();
        triangle.addPoint(loc.x, loc.y);//bottom right point
        triangle.addPoint(loc.x-50, loc.y);//bottom left point
        triangle.addPoint(loc.x-25, loc.y-50);
        g.setColor(Color.red);
        g.fillPolygon(triangle);
    }
        //moves canon left
    public void moveLeft(){
        if(getLocation().getX()>0 && getLocation().getX()<pnlWidth)
            getLocation().translate(-moveInc, 0);
    }
    //moves canon right
    public void moveRight(){
        if(getLocation().getX()<pnlWidth && getLocation().getX()>0)
            getLocation().translate(moveInc, 0);
        }
    }

}

我已经分离了这个测试类的关键部分。你能告诉我我做错了什么吗？