游戏主类，继承自JFrame类，负责游戏的全局控制。

内含：

1、一个GameCanvas画布类的实例引用，

2、一个保存当前活动块(ErsBlock)实例的引用，

3、一个保存当前控制面板（ControlPanel）实例的引用



ErsBox.java：

方格类，是组成块的基本元素，用自己的颜色来表示块的外观。

-The main game class, inherited from the JFrame class, is responsible for overall control of the game. Includes: 1, a type of canvas GameCanvas examples cited, 2, a block to preserve the current activities (ErsBlock) cited examples, 3, a preservation of the current control panel (ControlPanel) cited examples of ErsBox.java: grid type is the basic elements of the composition of the block, with its own color to indicate the appearance of block.