如果注释类的 subtitle 属性设置为非空白值，则它将显示在标注中.>

如果您需要存储带注释的数据但不显示在标注中，请为其创建一个单独的属性(未命名为 title ， subtitle ，或 coordinate ).

将字幕保留为空白，或者仅在注释类中不实现该属性(这是可选的).

In my app am adding subtitle to annotation pin but don't want to show with pin. I am just using it for coding purpose. How can I hide?

If the subtitle property of your annotation class is set to a non-blank value, it will display in the callout.

If you need to store data with the annotation but not display it in the callout, create a separate property for it (that's not named title, subtitle, or coordinate).

Leave subtitle blank or just don't implement the property in your annotation class (it's optional).