What is the appropriate UI set up for messaging functionality?

Question

I have an app which allows users to send messages to each. The process is accomplished by saving the sent messages in a local SQLite database, while actually sending the messages to a database and using push notifications to send the message to the recipient's SQLite database. The set up I have works fine. However, what I am confused about is how to set up the actual interactive UI for the user (I am using XCode). I figured it should be a UITableView with each table cell representing a message. However, with this approach I run into a few requirements:
Variable TextView Sizes
Just as with regular iOS messaging, the TextView's size needs to be variable, adjusting its dimensions to fit all of the text in each message. I do not know how to accomplish this. I have a general understanding of how to generally vary sizes, but no clue how to dynamically have it based on the text within that view.
Variable TextView Positions
Again, just as with regular iOS messaging, the textview needs to be offset to either the right or left side depending on whether the sender was the user or who the are conversing with, respectively. I also do not know how to do this, because it changes the center of the textview.
Non-selectability
Xcode allows cells to be pressed. Handling what happens after this selection can be achieved by the didSelectRowatIndexPath tableView function. I can simply not implement this, but clicking on the cell causes it to turn darker to indicate it has been pressed. I would like to eliminate this while retaining the ability to, say, select some of the text and copy and paste it or whatever (just like messaging works normally on your phone).
Other Approaches?
This is the real meat of the question. I have considered the above approach because that is all that I have been able to come up with based on my limited experience with XCode UI elements. If there is a better approach (perhaps even a pod or framework) for this purpose I would love to hear it. I do not need the messaging UI to look amazing, just clean and crisp.

Answer 1

I suggest the following:

Variable TextView Sizes:
I assume you do use auto layout. If you don’t yet, please consider using it since it make life much easier!
If you use a UITableView, you can adjust the height of its UITableViewCells dynamically, depending on the actual content by using self-sizing cells. You can find a tutorial how to do this here.
Variable TextView Positions:
I assume you have a UITextView within a table view cell. In this case, you have to set auto layout constraints to the borders of the cell’s contentView. If you define a custom subclass of a UITableViewCell, you can define in this class 2 IBOutlet properties that are linked to say the left and the right layout constraints (e.g. var leftLayoutConstraint: NSLayoutConstraint). Then, you can set the constraint’s constant property as required when the cell is laid out, i.e. in the layoutSubviews function of the custom table view cell.
Non-selectability:
I am not sure what you mean by „I can simply not implement this“. Please make sure that you set the delegate property of the UITableView to the view controller where you want to handle cell selection. Selecting a cell changes the cells color by default, but you can change this: In the storyboard, select your table view’s prototype cell, and open Xcode’s utility pane (top rightmost button). Under „Table view cell“ you find „Selection“ that you can set to „None“.

I hope this helps!