RootViewController.m
/* |
Copyright (C) 2014 Apple Inc. All Rights Reserved. |
See LICENSE.txt for this sample’s licensing information |
Abstract: |
The main UIViewController containing the app's user interface. |
*/ |
#import "RootViewController.h" |
// The value for the 'Text Color' setting is stored as an integer between |
// one and three inclusive. This enumeration provides a mapping between |
// the integer value, and color. |
typedef NS_ENUM(NSUInteger, TextColor) { |
blue = 1, |
red, |
green |
}; |
// It's best practice to define constant strings for each preference's key. |
// These constants should be defined in a location that is visible to all |
// source files that will be accessing the preferences. |
NSString* const kFirstNameKey = @"firstNameKey"; |
NSString* const kLastNameKey = @"lastNameKey"; |
NSString* const kNameColorKey = @"nameColorKey"; |
@interface RootViewController () |
// Values from the app's preferences |
@property (strong) NSString *firstName; |
@property (strong) NSString *lastName; |
@property (strong) UIColor *nameColor; |
@end |
@implementation RootViewController |
//| ---------------------------------------------------------------------------- |
- (void)viewDidLoad |
{ |
[super viewDidLoad]; |
// Only iOS 8 and above supports the UIApplicationOpenSettingsURLString |
// used to launch the Settings app from your application. If the |
// UIApplicationOpenSettingsURLString is not present, we're running on an |
// old version of iOS. Remove the Settings button from the navigation bar |
// since it won't be able to do anything. |
if (&UIApplicationOpenSettingsURLString == NULL) { |
self.navigationItem.leftBarButtonItem = nil; |
} |
} |
//| ---------------------------------------------------------------------------- |
- (void)viewWillAppear:(BOOL)animated |
{ |
[super viewWillAppear:animated]; |
// Load our preferences. Preloading the relevant preferences here will |
// prevent possible diskIO latency from stalling our code in more time |
// critical areas, such as tableView:cellForRowAtIndexPath:, where the |
// values associated with these preferences are actually needed. |
[self onDefaultsChanged:nil]; |
// Begin listening for changes to our preferences when the Settings app does |
// so, when we are resumed from the backround, this will give us a chance to |
// update our UI |
[[NSNotificationCenter defaultCenter] addObserver:self |
selector:@selector(onDefaultsChanged:) |
name:NSUserDefaultsDidChangeNotification |
object:nil]; |
} |
//| ---------------------------------------------------------------------------- |
- (void)viewWillDisappear:(BOOL)animated |
{ |
[super viewWillDisappear:animated]; |
// Stop listening for the NSUserDefaultsDidChangeNotification |
[[NSNotificationCenter defaultCenter] removeObserver:self name:NSUserDefaultsDidChangeNotification object:nil]; |
} |
//| ---------------------------------------------------------------------------- |
//! Unwind action for the Done button on the Info screen. |
// |
- (IBAction)unwindFromInfoScreen:(UIStoryboardSegue *)sender |
{ } |
#pragma mark - |
#pragma mark Preferences |
//| ---------------------------------------------------------------------------- |
//! Launches the Settings app. The Settings app will automatically navigate to |
//! to the settings page for this app. |
// |
- (IBAction)openApplicationSettings:(id)sender |
{ |
// UIApplicationOpenSettingsURLString is only availiable in iOS 8 and above. |
// The following code will crash if run on a prior version of iOS. See the |
// check in -viewDidLoad. |
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]]; |
} |
//| ---------------------------------------------------------------------------- |
// Handler for the NSUserDefaultsDidChangeNotification. Loads the preferences |
// from the defaults database into the holding properies, then asks the |
// tableView to reload itself. |
// |
- (void)onDefaultsChanged:(NSNotification *)aNotification |
{ |
NSUserDefaults *standardDefaults = [NSUserDefaults standardUserDefaults]; |
self.firstName = [standardDefaults objectForKey:kFirstNameKey]; |
self.lastName = [standardDefaults objectForKey:kLastNameKey]; |
// The value for the 'Text Color' setting is stored as an integer between |
// one and three inclusive. Convert the integer into a UIColor object. |
TextColor textColor = [standardDefaults integerForKey:kNameColorKey]; |
switch (textColor) { |
case blue: |
self.nameColor = [UIColor blueColor]; |
break; |
case red: |
self.nameColor = [UIColor redColor]; |
break; |
case green: |
self.nameColor = [UIColor greenColor]; |
break; |
default: |
NSAssert(NO, @"Got an unexpected value %@ for %@", @(textColor), kNameColorKey); |
} |
[self.tableView reloadData]; |
} |
#pragma mark - |
#pragma mark UITableViewDataSource |
//| ---------------------------------------------------------------------------- |
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section |
{ |
return 1; |
} |
//| ---------------------------------------------------------------------------- |
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath |
{ |
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"NameCell"]; |
cell.textLabel.text = [NSString stringWithFormat:@"%@ %@", self.firstName, self.lastName]; |
cell.textLabel.textColor = self.nameColor; |
return cell; |
} |
@end |
Copyright © 2014 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2014-09-17