如何使布尔值持续一定时间？

Question

I am trying to make an effect for my game that when the player uses it, the character runs faster, but I want to make the sodaEffect last for a certain amount of time, but i'm not sure how to do that. I am using Slick2D and LWJGL to make the game.

    public class MainMap extends BasicGameState {

    if(input.isKeyPressed(Input.KEY_I)) {
        sbg.enterState(5);
    }
    if(InventoryClass.sodaEffect == true) {
        InventoryClass.characterSpeed = 1f;
    }
    else{
        InventoryClass.characterSpeed = .1f;
    }}

    public class InventoryClass {

    public static boolean sodaEffect = false;
    }

Answer 1

Without exactely knowing what your InventoryClass does, I would do something like this:

public class InventoryClass {
    private final static long SODA_DURATION = 5000L;
    private static long sodaStartTime;

    public static void startSodaEffect() {
        sodaStartTime = System.currentTimeMillis();
    }

    public static boolean hasSodaEffect() {
        return (System.currentTimeMillis() - sodaStartTime) < SODA_DURATION;
    }
}

With this approach, you don't need additional libraries.