如何在所有视图控制器上设置一个标签来设置分数？

Question

我有一个标签，我需要它来显示每个ViewController上的分数，硬币等，这意味着当分数改变时，它会改变整个应用程序中的每个位置......

我试图设置一个标签来显示整个应用程序的分数，但我无法弄清楚如何！

请帮忙

这就是我在视图控制器中所拥有的：

 -(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];

}

我在其他PlayViewController中有一个动作（减去）-200硬币，但它在ViewController中没有更新？

Answer 1

一种方法是使用NSNotificationCenter。

将此代码添加到更改分数值的所有位置：

- (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];
}

在视图控制器的viewDidLoad方法中，添加以下代码：

- (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];
}

然后在视图控制器的某个位置添加此方法以更新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];
    }

在视图控制器中，添加dealloc：

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

注意：您应该根据存储和检索分数的方式调整代码。 即，如果您使用NSUserDefaults（请参阅@ erid的答案），CoreDate等。

Answer 2

使用NSUserDefaults存储数据（仅当从iOS设备中删除程序时才会删除数据，或者您可以手动将其删除）。

在NSUserDefaults上存储值

//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"];

重拾价值

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

您可以尝试将NSNotification添加到程序中，以便在设置为更改标签的NSString更改时对您进行通知，并且可以将此值设置为NSUserDefaults 。

正如大卫所说，这不是最好的方法，但是如果您需要保存数据直到应用程序关闭，您必须阅读更多关于单身人士的信息 。

希望能帮助到你