NSUserDefaults奇怪的行爲 - 更改存儲的值

Question

我正在構建一個點擊計數應用程序（例如：進入房間的人）。主要目標是能夠擁有多個櫃檯（例如：主廳櫃檯，白色櫃檯櫃檯，綠色房間櫃檯等）。

該應用程序包括：

1）計數器的列表 - CounterListTableViewController，具有功能列表

2）創建新的項目（計數器）計數器頁 - RowCounterViewController

問題＃1：在RowCounterViewController計數值被存儲到NSUserDefaults。敲擊後，讓我們說3次在計數器中，通過導航欄按鈕「返回」返回列表，然後返回到該計數器在UILabel中顯示3。到目前爲止，一切都很好，但如果我回到列表超過1次，數值開始改變。發生什麼事？

這是對形勢的NSLog上面解釋：

2015-01-02 23:51:56.243 RowCounter[8522:380477] { 
    0 = 0; 
    1 = 0; 
    2 = 0; 
} 
// here I tap 3 times in the counter with index "0" in the list 

2015-01-02 23:52:07.184 RowCounter[8522:380477] { 
    0 = 3; 
    1 = 0; 
    2 = 0; 
} 
// I return to the list and go back to the same counter, 3 times is there 

2015-01-02 23:52:11.594 RowCounter[8522:380477] { 
    0 = 0; 
    1 = 0; 
    2 = 0; 
} 
// I return again to the list and again back to the same counter, it now shows 0 (but should be 3) 

2015-01-02 23:52:17.902 RowCounter[8522:380477] { 
    0 = 0; 
    1 = 0; 
    2 = 0; 
} 
// I now go to the counter with index "1" and tap 5 times 

2015-01-02 23:52:27.591 RowCounter[8522:380477] { 
    0 = 0; 
    1 = 5; 
    2 = 0; 
} 
// I return to the list and go to a different counter with index "2", in the counter with index "1" count is 5 

2015-01-02 23:52:30.401 RowCounter[8522:380477] { 
    0 = 0; 
    1 = 5; 
    2 = 0; 
} 
// I again return to the list and again go to a different counter with index "2", in the counter with index "1" count is still 5 

2015-01-02 23:52:34.029 RowCounter[8522:380477] { 
    0 = 0; 
    1 = 5; 
    2 = 0; 
} 
// I again return to the list and again go to a different counter with index "2", in the counter with index "1" count is still 5 - So if not returning to the counter with count >0 it holds that count 

2015-01-02 23:52:37.144 RowCounter[8522:380477] { 
    0 = 0; 
    1 = 0; 
    2 = 0; 
} 
// I return to the list and go to the counter with index "1" and count 5 clears. 

問題2：這可能是連接到第一個問題，我失去了計數時，Home鍵被按下，但因爲我失去無論如何，如果第一個問題得到解決，這個問題就可以解決。

代碼，我存儲和加載視圖：

- (void)viewDidLoad { 
    [super viewDidLoad]; 

    // Do any additional setup after loading the view. 

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(saveCount) name:UIApplicationDidEnterBackgroundNotification object:nil]; 

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(saveCount) name:UIApplicationWillTerminateNotification object:nil]; 

    NSDictionary *dict = [[NSUserDefaults standardUserDefaults] objectForKey:@"saveCount"] ; 
    NSLog(@"%@", dict); 

    NSString *key = [NSString stringWithFormat:@"%ld", (unsigned long)_itemIndex] ; 
    NSInteger numCounter = [[dict objectForKey:key] intValue] ; 
    if (numCounter) { 
     // counter = [numCounter intValue] ; 
     count.text = [NSString stringWithFormat:@"%ld", (long)numCounter] ; 
    } else { 
     numCounter = 0 ; 
     count.text = @"0" ; 
    } 
} 


- (void)saveCount { 
    NSDictionary *dict = [[NSUserDefaults standardUserDefaults] objectForKey:@"saveCount"] ; 
    NSMutableDictionary *mDict = nil ; 
    if (dict == nil) 
     mDict = [NSMutableDictionary dictionary] ; 
    else 
     mDict = [dict mutableCopy] ; 

    NSString *key = [NSString stringWithFormat:@"%ld", (unsigned long)_itemIndex] ; 
    [mDict setObject:@(counter) forKey:key] ; 
    [[NSUserDefaults standardUserDefaults] setObject:mDict forKey:@"saveCount"] ; 
    [[NSUserDefaults standardUserDefaults] synchronize] ; 
} 

感謝您的幫助！

Answer 1

已經發現了問題：

我的註釋行counter = [numCounter intValue] 給了一個錯誤bad receiver type 'NSInteger' (aka "long")

起初我宣佈int counter 改成了NSInteger counter

註釋掉上面的行，並更改爲：

NSString *key = [NSString stringWithFormat:@"%ld", (unsigned long)_itemIndex] ; 
NSInteger numCounter = [[dict objectForKey:key] intValue] ; 
if (numCounter > 0) { 
    counter = numCounter; 
    count.text = [NSString stringWithFormat:@"%ld", (long)numCounter] ; 
} else { 
    numCounter = 0 ; 
    count.text = @"0" ; 
} 

Answer 2

此行似乎是不正確的：

NSInteger numCounter = [[dict objectForKey:key] intValue] ; 
if (numCounter) { 

您在這裏檢查，如果numCounter等於一個

我想這應該是

NSInteger numCounter = [[dict objectForKey:key] intValue] ; 
if (numCounter > 0) { 

但話又說回來，你可以重寫整個東西到

NSString *key = [NSString stringWithFormat:@"%ld", (unsigned long)_itemIndex]; 
NSNumber* numCounter = dict[key]; 
if(!numCounter) 
    numCounter = @0; 

count.text = [numCounter stringValue];