跳跃不起作用 Slick2D

Question

I have this code, and when I press space, it goes all weird. I have tested it, and jump() is being called when I press space. I don't receive an error for anything.

public static void update(int delta)
{
    if (!grounded && !jumping)
        y += gravity;
        if (y > 275)
        {
            grounded = true;
            jumpTime = 0;
        }
        if (jumping && jumpTime < maxJumpTime)
        {
            y -= jumpPower;
            jumpTime++;
        }
        if (jumpTime > maxJumpTime)
        {
            jumping = false;
            jumpTime = 0;
        }
        if (jumping)
        {
            grounded = false;
        }
}

public static void jump(int power)
{
    if (grounded)
    {
        jumpPower = power;
        grounded = false;
        jumping = true;
    } else
        return;
}

The variables are:

x
y 
gravity (1)
jumpTime
maxJumpTime (5)
jumpPower (1).

Answer 1

Without a better idea of what "going weird" means, I would assume it has something to do with you labeling your methods as static. I would think the compiler would get mad when you try and access a non-static variable (x and y) from a static context. Jumping and updating seem like things you want to be individual to the object not something that will affect all of the objects.

I would recommend giving this a read: http://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html