我正在嘗試根據隨機整數的值更改我擁有的圖像，但是，eclipse 表示 rand 整數需要一個主體。我已經嘗試過int rand = random.nextInt(4);但這也行不通。任何幫助將不勝感激。public class GrassTile extends Tile {    Random random = new Random();    static BufferedImage texture;    int rand;    rand = random.nextInt(4);    if (rand == 0) {        texture = Assets.grass0;    } else if(rand == 1) {        texture = Assets.grass1;    } else if(rand == 2) {        texture = Assets.grass2;    } else if(rand == 3) {        texture = Assets.grass3;    }    public GrassTile(int id) {        super(texture, id);    }}謝謝，JavaDev