/// <summary>
/// 获取Button下的Text文本（没有则为空）
/// </summary>
/// <param name="btn"></param>
/// <returns></returns>
public static string GetText(this Button btn)
{
var com = ButtonExtension.Get(btn.gameObject);
return(com != null?com.GetText() : string.Empty);
}
/// <summary>
/// 设置Button下的Text的文本（如果有的话）
/// </summary>
/// <param name="btn"></param>
/// <param name="str"></param>
public static void SetText(this Button btn, string str)
{
ButtonExtension.Get(btn.gameObject)?.SetText(str);
}