如何使用箭头键保持对象移动? [英] How do I keep an object moving using arrow keys?

问题描述

我正在做蛇游戏，我希望一旦按下按键，蛇就可以连续运动.因此，我按下了下键，即使释放键，它也会继续移动.现在，它只是在按住键的同时移动.

I am making a snake game, and I want my snake to be moving continuously once a key is pressed. So, I press the down key, and it keeps moving even if the key is released. Right now, it just moves while the key is being held down.

    public void keyPressed(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_DOWN) {
           mySegment[0].moveSouth();
           repaint();
        }
    else if (e.getKeyCode() == KeyEvent.VK_UP) {
        mySegment[0].moveNorth();
        repaint();
    }
    else if(e.getKeyCode() == KeyEvent.VK_LEFT){
        mySegment[0].moveWest();
        repaint();
    }
    else if (e.getKeyCode() == KeyEvent.VK_RIGHT){
        mySegment[0].moveEast();
        repaint();
    }

    for (int a = 0; a < 10; a++) {
        if (myFruit[a].distance (mySegment[0].getX(), mySegment[0].getY())                
        <= 20) {
            myFruit[a].hide();
        }
    }

"mySegment [0]"是蛇，"moveSouth"或任何方向只是将其在该方向上移动了5个像素

The "mySegment [0]" is the snake, and the "moveSouth" or whatever direction just moves it 5 pixels in that directin

推荐答案

如果您想让蛇保持运动，则需要某种游戏循环(如前所述).最简单的方法是使用一个包含当前方向的字段，然后根据输入进行设置.因此，这里有一些方法/类可以用来设置正确的方向/位置

If you want to keep the snake moving you need some kind of game-loop (as mentioned before). The easiest way is having a single field containing the current direction, and set it based on the input. So here are a few methods/classes you could use to set the correct direction/position

方向枚举

public enum  Direction
{
    NORTH, EAST, SOUTH, WEST;

    public Direction oposite()
    {
         switch(this)
         {
             case NORTH: return SOUTH;
             case SOUTH: return NORTH;
             case EAST: return WEST;
             case WEST: return EAST;
          }
    }
}

设置当前方向的方法. (假设存在一个名为"currentDirection"的字段，其中包含表示当前方向的枚举(方向))

The method to set the current direction. (This assumes there is a field named 'currentDirection' which contains an enum (Direction) representing the current direction)

  public void setDirection(Direction newDirection)
 {
      if(currentDirection != newDirection.oposite())
          currentDirection = newDirection;
 }

这是您游戏循环中的某个位置(计时器或while循环，其中包括睡眠"调用以防止CPU阻塞)

This is somewhere in your game loop (either an timer, or a while loop including a 'sleep' call to prevent CPU hugging)

     switch(currentDirection)
     {
          case NORTH: mySegment[0].moveNorth(); break;
          case EAST: mySegment[0].moveEast(); break;
          case SOUTH: mySegment[0].moveSouth(); break;
          case WEST: mySegment[0].moveWest(); break;
     }
     repaint();

当然不用调用"mySegment [0] .moveNorth();"或keyEvent的actionHandler中的等价物，则应仅调用"setDirection();"使蛇移动.

And of course instead of calling 'mySegment[0].moveNorth();' or someting equalivant in the actionHandlers for the keyEvents, you should only call 'setDirection();' to make the snake move.

希望这对您有所帮助.

这篇关于如何使用箭头键保持对象移动?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！