DesignableButton | Custom UIButton | User Interface library

I have Created IBDesignable and IBInspectable custom class to give shadow and corner radius for view

But When I assign Designable class to view, I get Designable Build Failed

This is my code

I don't know why my table view disappears after I reach the bottom of my table view.

here is the gif file of my problem: http://g.recordit.co/4hizPCyctM.gif

here is my code in my view controller

I have 2 UISwitch and a Button, in viewDidLoad, I set the button to be hidden and disabled, I want only my button to be not hidden if those 2 switch is in ON state, otherwise, I want my button to hide again. is there any method from UI Switch delegate that can be used ? how do I do that in Swift ?

here is the code I use

I am trying to make a FAQ view controller using table view, I need little bit fix in the UI. here is the display of my FAQ VC right now

(please ignore the red line)

as we can see, basically there are 2 row height, 80 & 160. if the row is tapped (selected) the row height will expand from 80 (yellow line) to 160 (purple line).

I want to make the row height under the last question is still 80 not 160. I have tried but I can't set the row below the last question. here is my code I use

I am beginner in programming. I actually have my own answer of this questions and the app worked as I am expected, but I am not sure if this is the correct way to to this.

This check out action will be triggered after the user click chechoutButton. but before before this chechoutButton.isEnabled , I have to make sure 3 parameters are available (not nil). before doing this check out action, I need 3 parameters :

1. get user's coordinate from GPS.
2. get user's location address from Google Place API
3. Get current date time from server for verification.

method to get user location address from Google Place API will be triggered only if I get the coordinate from GPS, and as we know, fetching data from the internet (to take date and time) also takes time, it should be done asynchronously.

how do I manage this checkoutButton only enabled if those 3 parameters are not nil ? Is there a better way according to apple guideline to do this

the simplified code are below

I am a beginner. I want to make a swift file that contains a code to make Designable UIImage, so I will not edit the UI element display by coding, just in Interface builder by assigning this swift file to UI class.

I can do something similar in UIButton, for example if i want to make round corner and add border to UIButton i can do something like this