Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Reading preferences in your application

From: iOS SDK and SQLite: Building Data-Driven Apps

Video: Reading preferences in your application

Now, we have a working settings bundle. We need to be able to read the values in our code. In this movie we'll look at how that is done. We'll go ahead and open the BWRSS-preferences that I created in the last movie. I'm going to open that in Xcode by double-clicking on the .xcode project file. So, this is the version that has these preferences Root.plist in it. I'm going to come up here into RSSDB and open the RSSDB.m.

Reading preferences in your application

Now, we have a working settings bundle. We need to be able to read the values in our code. In this movie we'll look at how that is done. We'll go ahead and open the BWRSS-preferences that I created in the last movie. I'm going to open that in Xcode by double-clicking on the .xcode project file. So, this is the version that has these preferences Root.plist in it. I'm going to come up here into RSSDB and open the RSSDB.m.

So, this is our data base routines, and I just closed the Utilities panel because we don't need that, it's taking up space here. If we look down here at the deleteOldItems, we'll see rather along SQL Query it takes up two strings. Two strings right next to each other in C or C++ or in Objective-C concatenates these two strings together. Objective-C has borrowed this even with its NSString literals. So, this is really all one string delete from blah, blah, blah, all the way up to this closing quote here.

Now, what we have here is a subquery. Everything in the parenthesis is a subquery. So, it's selecting items from the items table and ordering them by publication date with a limit of getMaxItemsPerFeed and then it's deleting everything that is not in that list. It's taking the newest so many items, and it's deleting everything else. So, this getMaxItemsPerFeed is the number of items that's being retained when we delete old items.

So, where is that defined? So, getMaxItemsPerFeed is up here, and this is actually reading from the user default. NSUserDefaults grabs our UserDefaults, and we can get our MaxItemsPerFeed by using objectForKey and using this string max_items_per_feed, and if we remember, down here in our Settings Bundle, our identifier MaxItemsPerFeed is used for that Multi Value where we select either 25, 50, 100 or 250.

You'll also notice that if we don't have a MaxItemsPerFeed, we set it to a default value, and that kDefault, that's defined in our header file and the default is 50. So let's run a little experiment here. I'm going to grab the MaxItemsPerFeed value, and I'm going to display it with NSlog. And I'm also going to display it after we've tested it for default. Press Command+S to save. I'm going to go ahead and run this in the simulator.

It's an interesting test because it's going to show one of the limitations of this settings interface. Now, the first thing I'm going to do when I run this in the simulator, I'm going to come over here to our iOS Simulator menu, and I'm going to say Reset Contents and Setting, and I'm going to press this Reset button. That resets my simulator to its default as if it's a brand-new phone out of the box, and you'll notice that it's also finish running and so I have to run it again. Now, we're running this fresh having never gone to the settings before.

When I select one of these feeds, this MaxItemsPerFeed gets called, and you'll notice that the value from the settings is null and after the test for default is 50. So, we get a null the first time we call it. Until you've actually gone to the settings app and selected something, you're not going to get a value and so you have to have a default value and set it to that default value, in case what you get from your settings is actually null. Now, when I come out here to my settings-- I'm going to press the Home button here.

I'm pressing Shift+Command+H on my keyboard for the Home button because my screen doesn't have one because this is getting scaled down. I'm going to slide over here and grab the settings app and come over here to BW RSS. If I select 50 again, and I double tap my Home button and come back to my BW RSS app, and I'll select this again, you'll see that I'm still getting that null, but if I come out here to my settings app, and I select a different value.

I'll select 100 and press, double tap my Home button and come out here and select my Feed again. Now, you'll notice that I'm getting that 100 value from the settings and after the test because it's not null, I go ahead and I leave that value alone. So, when you run your app, you're not going to actually get values from your settings until somebody goes to the settings app and actually changes something. Even just looking at the value or selecting the default value again, doesn't change something.

Now, when I bring it back to 50 again, now I'll pick up that 50. So, there we have the 50 before and after the test. So, we'll go ahead and delete my NSLog items here. Now, we can see that using the iOS Setting Interface is really quite easy, you just create the settings bundle, you put it in your settings, and you use the NSUserDefaults class to read those values.

Show transcript

This video is part of

Image for iOS SDK and SQLite: Building Data-Driven Apps
iOS SDK and SQLite: Building Data-Driven Apps

41 video lessons · 6430 viewers

Bill Weinman
Author

 
Expand all | Collapse all
  1. 8m 29s
    1. Welcome
      57s
    2. Exercise files
      2m 17s
    3. Course overview
      3m 4s
    4. Application overview
      2m 11s
  2. 14m 49s
    1. Prototyping in a testbed
      1m 27s
    2. Building the view controller
      3m 45s
    3. Coding the testbed
      7m 56s
    4. Using the testbed
      1m 41s
  3. 37m 49s
    1. Understanding SQLite in iOS
      1m 41s
    2. Creating an Objective-C interface for SQLite
      9m 57s
    3. Testing the BWDB interface in the sandbox
      7m 1s
    4. Designing a database schema
      8m 7s
    5. Supporting the application with a specific interface
      7m 7s
    6. Using C pointers with automatic reference counting (ARC)
      3m 56s
  4. 21m 18s
    1. Understanding the table view
      1m 33s
    2. Creating the view controller
      6m 39s
    3. Reading from the database
      13m 6s
  5. 33m 50s
    1. Understanding the parsing process
      1m 57s
    2. Creating the item view controller
      12m 25s
    3. Reading data from the internet
      5m 30s
    4. Parsing the feed with NSXMLParser
      8m 2s
    5. Updating the item view with the feed items
      5m 56s
  6. 40m 14s
    1. Understanding the modal view
      1m 47s
    2. Constructing the view controller
      15m 5s
    3. Finding a feed link in a web page
      8m 55s
    4. Parsing the feed with NSXMLParser
      5m 4s
    5. Delegating back to the parent view
      6m 11s
    6. Deleting feeds
      3m 12s
  7. 21m 5s
    1. Creating the web view class
      12m 33s
    2. Coding the web view
      5m 25s
    3. Viewing pages in Safari
      3m 7s
  8. 14m 3s
    1. Understanding the iOS preferences system
      1m 23s
    2. Creating the preferences plist in Xcode
      7m 20s
    3. Reading preferences in your application
      5m 20s
  9. 6m 15s
    1. Adding pull-to-refresh functionality
      2m 34s
    2. Implementing the pull-to-refresh gesture for iOS 6
      3m 41s
  10. 27m 1s
    1. Understanding split view
      1m 4s
    2. Coding the table views
      11m 24s
    3. Implementing the iPad detail view
      6m 35s
    4. Implementing the iPad modal view
      7m 58s
  11. 35s
    1. Goodbye
      35s

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ.

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed iOS SDK and SQLite: Building Data-Driven Apps.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferencesfrom the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Are you sure you want to delete this note?

No

Your file was successfully uploaded.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.