修改下蹲执行逻辑

1. 按向下的方向键，提示已经在下蹲躲避状态中； 2. 按向上的方向键，回复站立状态；

Author: Mr-susu

Assets/Behavioral Patterns/State Pattern/Exmaple4/DuckingState.cs

@@ -22,9 +22,14 @@ public void Update()
 
  public void HandleInput()
  {
- if (Input.GetKeyUp(KeyCode.DownArrow))
+ if (Input.GetKeyDown(KeyCode.DownArrow))
  {
- Debug.Log("get GetKeyUp.DownArrow!");
+ Debug.Log("已经在下蹲躲避状态中！");
+ return;
+ }
+ if (Input.GetKeyUp(KeyCode.UpArrow))
+ {
+ Debug.Log("get GetKeyUp.UpArrow!");
  _heroine.SetHeroineState(new StandingState(_heroine));
  }
  }