This action checks for the initial down press on a gamepad button for a given gamepad index. It will return true on the single game tick that the gamepad button is pressed down and false at all other times. If you enable the not modifier, this action will be reversed, and check if the button has not been pressed down, returning false on the game tick that it has been pressed down and true at all other times.
注意：如果要将动作添加进 "if" 动作块，它们应该被放置到动作的一边，如下图所示：
参数 描述 游戏手柄 The gamepad index. 按钮 The name of the button to check. 非 否定选项（true变为false，反之亦然)
The above action block code polls the button state of gamepad 0 every step and if a button is being held down it checks for the initial button down press. If the check is true on the initial down press, a sound is played, then, while the button is held down, the sprite blending is changed to red. If the button is not being held down, a check is done on the button release to reset the blending colour to white.