Secrets of nsfetchedresultscontroller happiness the dirty secret of nsfetchedresultscontroller is that it does not have to be used from the main thread. The controller uses the key path to split the results into sections passing nil indicates that the. Facebook is showing information to help you better understand the purpose of a page. The rbqfetchedresultscontroller frc is a replacement for nsfetchedresultscontroller that works with realm. I would enthusiastically recommend this book to all my upper elementary reading groups and class book clubs. The fetch tells the story of calder, a fetch, a death escort for 330 years who goes through death doors to fetch souls. Our titles are available on paper and electronically, and all our ebooks are drmfree. To use sections in a table view thats powered by core data and a fetched results controller, we need to specify a property called sectionnamekeypath. A fetched results controller nsfetchedresultscontroller is a very effective liaison between core data and a uitableview. Having read a certain slant of light also by laura whitcomb, one of my favourite books of last year, i looked forward to reading the fetch and i can honestly say, the fetch is another gem of a book by laura whitcomb. A fetched results controller manages the results of a fetch request. Books, screencasts, forums, articles, and more, all aimed at helping software developers get better and have more fun. Most reference books dont have retention and recall as a goal, but this book is about learning, so youll see some of the same concepts come up more than once. The earlier book was chiefly concerned with how management functions.
This article builds upon the last weeks blog post on core data. If you have heard about nsfetchedresultscontroller class for the first time, it is a class with which you can optimize your ios app to improve response time and reduce the memory overhead. Introducing the fetched results controller ios components and. Youve already seen how core data takes a huge amount of work away from you, which is great because it means you can focus on writing the interesting parts of your app rather than data management. When you create your nsfetchresultscontroller use the entity name for the books table in the fetch request. The greek name of the bible book of revelation, apoka. Other books can be added or deleted, but maths and science cannot be deleted,they will get added by default when new student is added. Managing records with fetched results controllers cocoacasts. Xcode seems to have successfully converted everything except fetchrequest and. How this focus is achieved in order to make the organization prosper and grow is the subject of this companion to his classic, the practice of management. The section name key path lets us sort the data into sections in our table view. The controller uses the key path to split the results into sections passing nil indicates that the controller should generate a single section. Using a cache can avoid the overhead of computing the section and index information.
The greatest benefits of using nsfetchedresultscontroller come when we use it to automatically update a table view when objects are added, updated, or removed from a core data data store. An application powered by core data needs to make sure the state of the persistent store is reflected by the user interface and vice. Displaying data with nsfetchedresultscontroller and swift. Even though the table view in our sample application will only have one section, lets ask the fetched results controller for the number of sections. The fetchedresultscontroller code simplifies the data display dilemma when youre using core data. Each section contains the quotes of a particular author. The effective business, peter drucker observes, focuses on opportunities rather than problems. Problem with objectivec troubleshooting apple community. You configure a fetch results controller using a fetch request that specifies the entity, an array containing at least one sort ordering, and optionally a filter predicate. The dog crashes through waves and paddles next to leaping dolphins. And we want you to finish the book remembering what youve learned. In the previous installments of this series, we covered the fundamentals of the core data framework.
Jesse is heard regularly on the roundtable, a program of wamc public radio for the northeast. The number of sections contained in the table view after the update 5 must be equal to the number of sections contained in the table view before the update 6, plus or minus the number of sections inserted or deleted 0 inserted, 0 deleted. Introducing the fetched results controller a fetched results controller nsfetchedresultscontroller is a very effective liaison between core data and a uitableview. Rbqfetchedresultscontroller supports tableview sections and implements a dropin replacement delegate to pass the changes to the tableview for section and row animations. If you saw the movie fletch with chevy chase, you can just see and hear chevy chase delivering the lines. Add sections to table view with nsfetchedresultscontroller. As we all know both uitableview and uicollectionview is constructed with sections and rows for each of those section.
I am writing a small app in which i uses coredata, i have data like subjects which contains maths, science, and other books. To validate that you are honoring all of the threading rules its common to add the following to a project scheme under run arguments arguments passed on. This tutorial introduces you to the, almost magical, nsfetchedresultscontroller class. First things first, though with a core data data store seeded with. My books are howto guides that provide scenariobased solutions for common challenges. One distinct difference in a head first book is that we want you to really get it. This peoplebook covers the concepts of peoplecode, the programming language used in the development of oracle s peoplesoft applications. If you want to follow along, download the source files of this tutorial at the bottom of the tutorial. The nsfetchedresultscontroller class isnt an essential component of a core data application, but it makes working with collections of managed objects much easier. An application powered by core data needs to make sure the state of the persistent store is reflected by the user.
If you decide to have one model shared throughout your app the observer pattern kvo will definitely help manage the complexity. Exploring the fetched results controller delegate protocol. Presently, most of the developers load all of the failedbanksinfo objects from the database into memory at once. In the part 1 of the series i explained what the core data stack is and how to create a data model for a simple application. For the managed object context, we just pass in our context. Optionally, the name of the cache file the controller should use passing nil prevents caching. Once you submit a book fetch request, we stay on the lookout for your book. Realm class requires a primary key to work with rbqfetchedresultscontroller. Pragpub january 2010 touching the core the pragmatic. Optimizing core data performance using nsfetchedresultscontroller. The swift api mirrors objectivec with the following classes. In this article, we will build a small but complete core data backed application. Uitable view expects its data source to provide cells as an array of sections made up of rows. Want to learn how to use nsfetchedresultscontroller class to easily.
In this tutorial, well also meet another star player of the core data framework, the nsfetchedresultscontroller class. And the fetched results controller also constructed in such a way with both sections and rows for each section which will match for the uitableview uicollectionview data source and can be used for it. The bnr core data stack is a small swift framework that makes it both easier and safer to use core data. Once the uitableviewdatasource methods are implemented, the implementation of mainviewcontroller is complete for this example. Entering last name, first initial will get you the best results. The cocoapods website has an optional integration with appsight. The fetched results controller provides section titles, which are the values of the attribute specified as the. Weve included the sample project in several stages so that the code on github matches up with the code snippets in the book as best as possible. Within my guides, youll find prescriptive guidance in the form of timeless principles, success patterns, proven practices, and emerging practices. Optionally, a key path on result objects that returns the section name. The fetched results controller provides a way to set up a fetch request so that the results are returned in sections and rows, accessible by index paths. While table views can be used in several ways, fetched results controllers primarily assist you with a master list view. Fetching is a funny, emotional, sometimes silly story of 5 friends that are done being bullied. The combination of an nsfetchedresultscontroller and a uitableview provides a powerful way to integrate core data with a user interface.
Whenever a book gets added to our inventory, book fetch looks to see if it matches your request. As you can see, we can read the sections array, each of which contains an array of nsfetchedresultssectioninfo objects describing the items in that section. You might think its a rare and valuable book but dont know where to find its value. Book fetch matches the title you enter from left to right, not by keyword. A veteran developer on all ios and os x products, he is also the author of ios app development for dummies. Coredatamagical recordnsfetchedresultscontrollerfetchedresultscontrollerfindall. Do you have an old or antiquarian book and would like to know its value. One very simple method of finding an approximate value of a book is to search for similar copies on and see what prices are being asked. In two of the spreads, hurley cleverly turns the book sideways so the longer spreads can. Then run pod install in your code, import the framework as bnrcoredatastack contributing. Fetchedresultscontroller with sections stack overflow. Please see our guide to contributing to the coredatastack debugging tips. This name indicates the meaning of revelation it uncovers matters that had been hidden and discloses events that would happen long after it was written. In her new graphic memoir, nicole georges suggests the two questions are closely.
Nsfetchedresultscontroller core data apple developer. The application that were about to create manages a list of todo. In this tutorial, we add sections to the table view of quotes. We do this by calling sections on it, which returns an array of objects that conform to the nsfetchedresultssectioninfo protocol. Our fetchedresultscontroller sends swifty delegate messages, rather than a mess of optionals. The controller and delegate follow the same paradigm as nsfetchedresultscontroller, and allow the developer to monitor changes of a rlmobject subclass. You can also share just some of the data like maybe the book object gets shared with the book, bookmark, and notes view controllers because you. Enter isbn with 10 digits, excluding spaces or dashes. Its time we put our knowledge to use by building a simple application powered by core data. Add sections to table view with nsfetchedresultscontroller and swift plus in this tutorial, we add sections to the table view of quotes. Anyway, that will create a nsfetchedresultscontroller with the sections in. This pdf file contains pages extracted from core data in objectivec, third edition, published by the pragmatic bookshelf. The social issues dealt with in fetching are real and kids ages 1014 will easily relate. Perfect in its pacing and just enough left to your imagination to make it fun.
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