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[self dismissModalViewControllerAnimated:YES];

}

There’s not really much here that should throw you. The new method, refreshFields, does nothing more than grab the standard user defaults, and sets the text property of all the labels to the appropriate object from the user defaults, using the key values that we put in our plist file. Notice that for warpFactorLabel, we’re calling stringValue on the object returned. All of our other preferences are strings, which come back from the user defaults as NSString objects. The preference stored by the slider, however, comes back as an NSNumber, so we call stringValue on it to get a string representation of the value it holds.

After that, we fleshed out the viewDidAppear: method, where we call our refreshFields method. We call refreshFields again when we are notified that the flipside controller is being dismissed. This will cause our displayed fields to be set to the appropriate preference values when the view loads, and then to be refreshed when the flipside view is swapped out. Because the flipside view is handled modally, with the main view as its modal parent, the BIDMainViewController‘s viewDidAppear: method will not be called when the flipside view is dismissed. Fortunately, the Utility Application template we chose has very kindly provided us with a delegate method we can use for exactly that purpose.

Registering Default Values

We’ve created a settings bundle, including some default settings for a few values, to give the Settings app access to our app’s preferences. We’ve also set up our own app to access the same information, with a GUI to let the user see and edit it. However, one piece is missing: our app is completely unaware of the default values specified in the settings bundle. You can see this for yourself by deleting the AppSettings app from the iOS simulator or the device you’re running on (thereby deleting the preferences stored for the app), and then running it from Xcode again. At the start of a fresh launch, the app will show you blank values for all the settings. Even the default values for the warp drive settings, which we defined in the settings bundle, are nowhere to be seen. If you then switch over to the Settings app, you’ll see the default values, but unless you actually change the values there, you’ll never see them back in our AppSettings app!

The reason our setting disappeared is that our app knows nothing about the settings bundle it contains. So, when it tries to read the value from NSUserDefaults for warpFactor and finds nothing saved under that key, it has nothing to show us. Fortunately, NSUserDefaults includes a method called registerDefaults: that lets us specify the default values that we should find if we try to look up a key/value that hasn’t been set. To make this work throughout the app, it’s best if this is called early during app startup. Select BIDAppDelegate.m, and include this header file somewhere at the top of the file, so we can access the key names we defined earlier:

#import "BIDMainViewController.h"

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Then modify the application:didFinishLaunchingWithOptions: method as shown here:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{

// Override point for customization after application launch.

NSDictionary *defaults = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithBool:YES], kWarpDriveKey, [NSNumber numberWithInt:5], kWarpFactorKey, @"Greed", kFavoriteSinKey,

nil];

[[NSUserDefaults standardUserDefaults] registerDefaults:defaults]; return YES;

}

The first thing we do here is create a dictionary containing three key/value pairs, one for each of the keys available in Settings that requires a default value. We’re using the same key names we defined earlier, to reduce the risk of mistyping a key name. Then we pass that entire dictionary to the standard NSUserDefaults instance. From that point on, NSUserDefaults will give us the values we specify here, as long as we haven’t set different values either in our app or in the Settings app.

This class is complete. You should be able to compile and run your application. It will look something like Figure 12–7, except yours will be showing whatever values you entered in your Settings application, of course. Couldn’t be much easier, could it?

Changing Defaults from Our Application

Now that we have the main view up and running, let’s build the flipside view. As you can see in Figure 12–31, the flipside view features our warp drive switch, as well as the warp factor slider. We’ll use the same controls that the Settings application uses for these two items: a switch and a slider. In addition to declaring our outlets, we’ll also declare a method called refreshFields, just as we did in BIDMainViewController, and two action methods that will be triggered by the user touching the controls.

Figure 12–31. Designing the flipside view in Interface Builder

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Select BIDFlipsideViewController.h, and make the following changes:

#import <UIKit/UIKit.h>

@class BIDFlipsideViewController;

@protocol BIDFlipsideViewControllerDelegate

- (void)flipsideViewControllerDidFinish:(BIDFlipsideViewController *)controller; @end

@interface BIDFlipsideViewController : UIViewController

@property (weak, nonatomic) id <BIDFlipsideViewControllerDelegate> delegate;

@property (weak, nonatomic) IBOutlet UISwitch *engineSwitch; @property (weak, nonatomic) IBOutlet UISlider *warpFactorSlider;

-(void)refreshFields;

-(IBAction)engineSwitchTapped;

-(IBAction)warpSliderTouched;

-(IBAction)done:(id)sender;

@end

NOTE: Don’t worry too much about the extra code here. As you saw before, the Utility Application template makes BIDMainViewController a delegate of the BIDFlipsideViewController. The extra code here that hasn’t been in the other file templates we’ve used implements that delegate relationship.

Now, save your changes and select MainStoryboard.storyboard to edit the GUI in Interface Builder, this time focusing on the Flipside View Controller Scene. Hold down the option key and expand Flipside View Controller and everything below it. Next, double-click the flipside view title in the title bar and change it from Title to Warp Settings.

Next, select the View in the Flipside View Controller Scene, and then bring up the attributes inspector. First, change the background color by using the Background popup to select Light Gray Color. The default flipside view background color is too dark for black text to look good, but light enough that white text is hard to read.

Next, drag two Labels from the library and place them on the View window. Double-click one of them, and change it to read Warp Engines:. Double-click the other, and call it Warp Factor:. You can use Figure 12–31 as a placement guide.

Next, drag over a Switch from the library, and place it against the right side of the view, across from the label that reads Warp Engines. Control-drag from the Flipside View Controller icon to the new switch, and connect it to the engineSwitch outlet. Then control-drag from the switch back to the Flipside View Controller icon, and connect it to the engineSwitchTapped action.

Now drag over a Slider from the library, and place it below the label that reads Warp Factor:. Resize the slider so that it stretches from the blue guideline on the left margin to

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the one on the right, and then control-drag from the Flipside View Controller icon to the slider, and connect it to the warpFactorSlider outlet. Then control-drag from the slider to

Flipside View Controller, and select the warpSliderTouched action.

Single-click the slider if it’s not still selected, and bring up the attributes inspector. Set

Minimum to 1.00, Maximum to 10.00, and Current to 5.00. Next, select turtle.png for Min Image and rabbit.png for Max Image (you did drag them into the project, right?).

Now, let’s finish the flipside view controller. Select BIDFlipsideViewController.m, and make the following changes:

#import "BIDFlipsideViewController.h"

#import "BIDMainViewController.h"

@implementation BIDFlipsideViewController

@synthesize delegate = _delegate;

@synthesize engineSwitch; @synthesize warpFactorSlider;

.

.

.

- (void)viewDidLoad { [super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

[self refreshFields];

}

- (void)refreshFields {

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults]; engineSwitch.on = [defaults boolForKey:kWarpDriveKey]; warpFactorSlider.value = [defaults floatForKey:kWarpFactorKey];

}

- (IBAction)engineSwitchTapped {

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults]; [defaults setBool:engineSwitch.on forKey:kWarpDriveKey];

}

- (IBAction)warpSliderTouched {

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults]; [defaults setFloat:warpFactorSlider.value forKey:kWarpFactorKey];

}

.

.

.

Add the following lines of code to the existing viewDidUnload method:

- (void)viewDidUnload { [super viewDidUnload];

// Release any retained subviews of the main view.

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