如何在所有视图控制器上设置一个标签来设置分数？

Question

I have a label and I need it to show the score, coins ect on every ViewController, That means when The score changes it changes every where throughout the whole app...

I've tried to set a label to show score on the whole app but I cant figure out how!

Please help

This is what I have so Far In the View Controller:

 -(void)viewDidLoad
{
{
[super viewDidLoad];


    NSError *error;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); //1
    NSString *documentsDirectory = [paths objectAtIndex:0]; //2
    path = [documentsDirectory stringByAppendingPathComponent:@"SettingsList.plist"]; //3

    NSFileManager *fileManager = [NSFileManager defaultManager];

    if (![fileManager fileExistsAtPath: path]) //4
    {
        NSString *bundle = [[NSBundle mainBundle] pathForResource:@"SettingsList"ofType:@"plist"]; //5 //5

        [fileManager copyItemAtPath:bundle toPath: path error:&error]; //6
    }

    savedStock = [[NSMutableDictionary alloc] initWithContentsOfFile: path];

    nPoint = [[savedStock objectForKey:@"point"] intValue];
    [giftAmount setText:[NSString stringWithFormat:@"%d",nPoint]];

[self updateCurrencyBalance];
[self zoneLoading];
}

//adcolony
- (void) viewDidAppear:(BOOL)animated
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateCurrencyBalance) name:kCurrencyBalanceChange object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(zoneReady) name:kZoneReady object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(zoneOff) name:kZoneOff object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(zoneLoading) name:kZoneLoading object:nil];
}

// Get currency balance from persistent storage and display it
- (void)updateCurrencyBalance {
NSNumber* wrappedBalance = [[NSUserDefaults standardUserDefaults] objectForKey:kCurrencyBalance];
NSUInteger balance = wrappedBalance && [wrappedBalance isKindOfClass:[NSNumber class]] ? [wrappedBalance unsignedIntValue] : 0;
[giftAmount setText:[NSString stringWithFormat:@"%u", balance]];

[savedStock setObject:[NSNumber numberWithFloat:nPoint = balance] forKey:@"point"];
[savedStock writeToFile: path atomically:YES];

}

I have an action in the other PlayViewController which (minusus) -200 coins, but its not updating in the ViewController?

Answer 1

One way is to use NSNotificationCenter.

Add this code to all the places that change the value of your score:

- (void)updateScore:(NSNumber *)newValue
    // update the score
    self.score = newValue;

    // create an dictionary object containing the score to be sent with the notification
    NSMutableDictionary* userInfo = [NSMutableDictionary dictionary];
    [userInfo setObject:self.score forKey:@"score"];

    // Add this to send a notification to all the listeners in the whole app
    [[NSNotificationCenter defaultCenter] postNotificationName:@"NotificationScoreChanged" object:nil userInfo:userInfo];
}

In the viewDidLoad methods of your view controllers, add this code:

- (void)viewDidLoad:(BOOL)animated
{
    [super viewDidLoad:animated];

    // Add this code to start receiving notifications (become a listener)
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(scoreChanged:) name:@"NotificationScoreChanged" object:nil];
}

Then somewhere in your view controllers, add this method to update your UI:

- (void)scoreChanged:(NSNotification *)notification
{
   // retrieve the score results
    if ([notification.name isEqualToString:@"NotificationScoreChanged"])
    {
        NSDictionary *userInfo = notification.userInfo;
        NSNumber *score = [userInfo objectForKey:@"score"];

        // and update your labels
        self.scoreLabel.text = [score description];
    }

And in your view controllers, add dealloc:

- (void)dealloc
{
    //Unregister yourself (stop listening)
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

Note: you should adapt the code depending on how you store and retrieve your score. Ie, if you use NSUserDefaults (see @erid's answer), CoreDate, etc.

Answer 2

Use NSUserDefaults for storing data (Data gets deleted only when program is removed from iOS Device or you can remove it manually).

Storing Value on NSUserDefaults

//text is your label.text, and each time you change it, save it to user details
NSString *text;

//Store them to NSUserDefaults with a specific key
[[NSUserDefaults standardUserDefaults] setObject:text forKey:@"label"];

Getting value back

NSString *textValue = [[NSUserDefaults standardUserDefaults] objectForKey:@"label" ];
label.text = textValue;

You can try adding NSNotification to your program to notificate you when the NSString you set to change the label changes, and there you can set this value to NSUserDefaults .

As David said this is not the best way to do this, but you have to read more about Singletons if you need to save your DATA until the app is closed.

Hope it helps