Master-Detail Application Structure Notes

By Nicholas Duchon.

Here is the basic structure of the Master-Detail template.

In the storyboard, we have the following:

Element	Comments
Navigation Controller	Start of program Controls segues between master and detail views sets up the controller area at the top of the views
Cav Master View Controller	Sets up the edit and add buttons Table presentation of records in one table Includes setting up the links to the detailed view of each element in the table
Cav Detail View Controller	Gets a reference to a particular element in the table Presents information about that element Allows users to change values Updates database upon exiting this view

Colors:

orange - things to leave alone
green - things related to the GUI that you will want to change
yellow - things related to the DB that you will want to change

Class / File	Methods / Variables	Comments
cavAppDelegate.h	UIResponder
	window
	managedObjectContext
	managedObjectModel
	persistentStoreCoordinator
	saveContext
	applicationDocumentsDirectory
cavAppDelegate.m	application
	applicationWillResignActive
	applicationDidEnterBackground
	applicationWillEnterForeground
	applicationDidBecomeActive
	applicationWillTerminate
	saveContext
	managedObjectContext
	managedObjectModel
	persistentStoreCoordinator
	applicationDocumentsDirectory
Main.storyboard		information about the views, and the layout of the GUI objects in them
cavMasterViewController.h	UITableViewController	reference to the master view object
	fetchedResultsController	from the DB
	managedObjectContext	an internal reference to some or all of a DB
cavMasterViewController.m	configureCell	interface prototype - see below for implementation
	awakeFromNib	Called after all NIB (GUI) objects have been created - trivial here
	viewDidLoad	Often trivial, but in this template two buttons are added to the master view: > edit > + to add a new event (= new record in the database)
	didReceiveMemoryWarning	Trivial here, real apps should do something here
	insertNewObject	respond to + key, create new record The right place to give record fields default values
	numberOfSectionsInTableView	return the number of entries in the table in this case, the number is the number of records in the database for this table
	tableView - numberOfRowsInSection	sections are a way to create groups in a table - in this case, it looks like just one
	tableView - cellForRowAtIndexPath	controller calls this to get the cell at an index value
	tableView - canEditRowAtIndexPath	yes, in our case
	tableView - commitEditingStyle	possible styles are delete, insert or none - in our case, the code responds to delete by deleting the object in the context then saving the context to the database
	tableView - canMoveRowAtIndexPath	rearrange rows? in our case, no
	prepareForSegue	There is probably no reason for you to change this code. called when the user touches any cell - sets up the call to the detailed view so that view is focused on the record touched by the user set up by a segue in Xcode from the cell to the detailed view for more details, see reference for UIStoryboardSegue information about the connection between the source object (row in table) to destination (detail view)
	fetchedResultsController	fetch the data from a the database by table name so the table name needs to match the Entity name in the database puts the result into the managedObjectContext variable in the template code
	controllerWillChangeContent	trivial for the template - calls the UITableView method
	controller - didChangeSection	updates display when records are added or deleted
	controller - didChangeObject	updates the table on insert, delete, update and move events
	controllerDidChangeContent	template just stops updating
	configureCell	template sets display text for cell, could change the cell contents
cavDetailViewController.h	UIViewController
	detailItem	change type from id to NSManagedObject
	detailDescriptionLabel
cavDetailViewController.m	configureView	prototype, see below for function
	setDetailItem	default is ok
	configureView	update the fields to display the information in the record
	viewDidLoad	super and call configureView
	didReceiveMemoryWarning	super, and whatever
	hideKeyboard	new method connected to huge transparent background button to dismiss the keyboard
	viewWillDisappear	new method to respond to leaving the detailed view by updating the database
Images.xcassets		images used by the app - icons, for example
cave.scdatamodeld		Information about the GUI interface to define the DB stucture
Frameworks	Foundation	The NS stuff
	CoreGraphics	Needed to draw in an app
	UIKit	Objects and events for a GUI
	CoreData	Handling the SQLite DB
	XCTest	Testing stuff