public BackGround(int index) {
		this.index = index;

		if (index != 2) {
			flag = false;
			bgImage = ResLoader.bgImage;
		} else {
			flag = true;
			bgImage = ResLoader.endImage;
		}

		switch (index) {
		case 0: {
			for (int i = 0; i < 15; ++i) {
				obstacles.add(new Obstacle(i * 60, 540, 9, this));
			}

			// 绘制砖块和？
			obstacles.add(new Obstacle(120, 360, 4, this));
			obstacles.add(new Obstacle(300, 360, 0, this));
			obstacles.add(new Obstacle(360, 360, 4, this));
			obstacles.add(new Obstacle(420, 360, 0, this));
			obstacles.add(new Obstacle(480, 360, 4, this));
			obstacles.add(new Obstacle(540, 360, 0, this));
			obstacles.add(new Obstacle(420, 180, 4, this));

			// 绘制水管
			obstacles.add(new Obstacle(660, 540, 6, this));
			obstacles.add(new Obstacle(720, 540, 5, this));
			obstacles.add(new Obstacle(660, 480, 8, this));
			obstacles.add(new Obstacle(720, 480, 7, this));

			// 加入隐藏的砖块
			obstacles.add(new Obstacle(660, 300, 3, this));

			// 绘制敌人（出现黄线就在private List allEnemy的List后面加泛型<Enemy>）
			enemies.add(new Enemy(600, 480, true, 1, this));
			enemies.add(new Enemy(690, 540, true, 2, 420, 540, this));
		}
			break;

		case 1: {
			for (int i = 0; i < 15; ++i) {
				if (i != 10) {
					obstacles.add(new Obstacle(i * 60, 540, 9, this));
				}
			}
			obstacles.add(new Obstacle(60, 540, 6, this));
			obstacles.add(new Obstacle(120, 540, 5, this));
			obstacles.add(new Obstacle(60, 480, 6, this));
			obstacles.add(new Obstacle(120, 480, 5, this));
			obstacles.add(new Obstacle(60, 420, 8, this));
			obstacles.add(new Obstacle(120, 420, 7, this));

			obstacles.add(new Obstacle(240, 540, 6, this));
			obstacles.add(new Obstacle(300, 540, 5, this));
			obstacles.add(new Obstacle(240, 480, 6, this));
			obstacles.add(new Obstacle(300, 480, 5, this));
			obstacles.add(new Obstacle(240, 420, 6, this));
			obstacles.add(new Obstacle(300, 420, 5, this));
			obstacles.add(new Obstacle(240, 360, 8, this));
			obstacles.add(new Obstacle(300, 360, 7, this));
		}
			break;

		case 2: {
			for (int i = 0; i < 15; ++i) {
				obstacles.add(new Obstacle(i * 60, 540, 9, this));
			}
			obstacles.add(new Obstacle(550, 180, 11, this));
			obstacles.add(new Obstacle(550, 480, 2, this));
		}
			break;

		default:
			break;
		}
	}