所以，您想保留位置随时间变化的随机变化，还希望通过键盘输入添加变化，对吧?！

so, you want to keep the the random changes of the position by time and also add a change by keyboard inpput , right?!

尝试:

counterTime += Gdx.graphics.getDeltaTime();
time += delta;
if(counterTime > 2f ) {// each second ==> one call to position random

    position = new Vector2(this.mari.x, this.mari.y);
    counterTime =0f;


}else { // between 2 seconds
    if(Gdx.input.isKeyPressed(Keys.B)) { // if "B" of Keyboard is pressed
        counterTime =3f; // go directly to the next random position

    }
}