如何检测键盘输入？

Question

I am trying to make a square in a JFrame to move around the frame by detecting keyboard input. I tried looking on the internet and that is where I got the keyPressed() method from. What I am looking for is how to declare it in the main() method so it will actually update x and y. Please try to keep it as simple as possible.

public class Game1{
public static int x = 1;
public static int y = 1;

static GraphicsClass graphics = new GraphicsClass();
static JFrame frame = new JFrame("Test");

public static void main(String[] args){
    frameInit();
    while(true){
        //The problematic line, how do I declare it:
        keyPressed();
        frame.add(BorderLayout.CENTER, graphics);
        frame.repaint();
    }
}

public static void keyPressed(KeyEvent i){
    int e = i.getKeyCode();
    while(e == KeyEvent.VK_UP){
        y--;
    }
    while(e == KeyEvent.VK_DOWN){
        y++;
    }
    while(e == KeyEvent.VK_RIGHT){
        y++;
    }
    while(e == KeyEvent.VK_LEFT){
        x--;
    }
}

public static void frameInit(){
    frame.setSize(500, 500);
    frame.setVisible(true);
    frame.setResizable(false);
}
}

Answer 1

You should implements keyListener interface. Try this..

public class Game1 extends JFrame implements KeyListener{

public static int x = 1;

public static int y = 1;

static GraphicsClass graphics = new GraphicsClass();

static JFrame frame = new JFrame("Test");

public static void main(String[] args){

frameInit();

while(true){

    //The problematic line, how do I declare it:

    keyPressed();

    frame.add(BorderLayout.CENTER, graphics);

    frame.repaint();
}

}

Answer 2

If you want to keep this as simple as possible you should create your Swing-Application by using Netbeans. It has a nice Form-Designer built in where you can add a KeyListener just with a click. You don't even have to care about a main-method which is also generated.