iOS-NSUserDefaults值为'；返回null；valueForKey'；但不是'；t空_Ios_Null_Nsuserdefaults

iOS-NSUserDefaults值为'；返回null；valueForKey'；但不是'；t空

ios

iOS-NSUserDefaults值为'；返回null；valueForKey'；但不是'；t空,ios,null,nsuserdefaults,Ios,Null,Nsuserdefaults,我试图通过检索每个产品标识符的NSUserDefaults值来查看用户是否进行了购买。当购买产品并正确设置时，我会保存该值调用此命令时，键值对正确显示： NSLog(@"%@", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]); "com.COMPANY.PRODUCTIDENTIFIER" = 1; for (NSString * productIdentifier in _productIde

我试图通过检索每个产品标识符的NSUserDefaults值来查看用户是否进行了购买。当购买产品并正确设置时，我会保存该值

调用此命令时，键值对正确显示：

NSLog(@"%@", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]);

"com.COMPANY.PRODUCTIDENTIFIER" = 1;

    for (NSString * productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)

    for (NSString *productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        NSLog(@"Static Key: %d",[[NSUserDefaults standardUserDefaults] boolForKey:@"com.COMPANY.PRODUCTIDENTIFIER"]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)   
2013-03-10 17:45:13.611 COMPANY[1140:907] Static Key: 1

如下所示：

NSLog(@"%@", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]);

"com.COMPANY.PRODUCTIDENTIFIER" = 1;

    for (NSString * productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)

    for (NSString *productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        NSLog(@"Static Key: %d",[[NSUserDefaults standardUserDefaults] boolForKey:@"com.COMPANY.PRODUCTIDENTIFIER"]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)   
2013-03-10 17:45:13.611 COMPANY[1140:907] Static Key: 1

但当我尝试实际验证特定键值时，它总是返回null:

NSLog(@"%@", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]);

"com.COMPANY.PRODUCTIDENTIFIER" = 1;

    for (NSString * productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)

    for (NSString *productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        NSLog(@"Static Key: %d",[[NSUserDefaults standardUserDefaults] boolForKey:@"com.COMPANY.PRODUCTIDENTIFIER"]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)   
2013-03-10 17:45:13.611 COMPANY[1140:907] Static Key: 1

结果是：

NSLog(@"%@", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]);

"com.COMPANY.PRODUCTIDENTIFIER" = 1;

    for (NSString * productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)

    for (NSString *productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        NSLog(@"Static Key: %d",[[NSUserDefaults standardUserDefaults] boolForKey:@"com.COMPANY.PRODUCTIDENTIFIER"]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)   
2013-03-10 17:45:13.611 COMPANY[1140:907] Static Key: 1

注意-以上两个方法都是按此顺序在同一个方法中调用的，因此应用程序尚未加载默认值或诸如此类的内容都没有问题，因为值是通过“dictionaryRepresentation”方法正确显示的。此外，公司和产品标识已被替换为隐私标识。真正的应用程序中没有输入错误，所以这不是问题所在

更新

好的，这很有趣。如果使用静态字符串作为键，它将返回正确的值。但使用“productIdentifier”（即NSString）则不会，即使将“productIdentifier”记录为完全相同的字符串。。。有什么想法吗

代码：

NSLog(@"%@", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]);

"com.COMPANY.PRODUCTIDENTIFIER" = 1;

    for (NSString * productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)

    for (NSString *productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        NSLog(@"Static Key: %d",[[NSUserDefaults standardUserDefaults] boolForKey:@"com.COMPANY.PRODUCTIDENTIFIER"]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)   
2013-03-10 17:45:13.611 COMPANY[1140:907] Static Key: 1

结果：

NSLog(@"%@", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]);

"com.COMPANY.PRODUCTIDENTIFIER" = 1;

    for (NSString * productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)

    for (NSString *productIdentifier in _productIdentifiers) {
        NSLog(@"ProductIdentifier: %@",productIdentifier);
        NSLog(@"Defaults Value: %@",[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]);
        NSLog(@"Defaults Bool: %d",[[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier]);
        NSLog(@"Defaults Object: %@",[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]);
        NSLog(@"Static Key: %d",[[NSUserDefaults standardUserDefaults] boolForKey:@"com.COMPANY.PRODUCTIDENTIFIER"]);
        BOOL productPurchased = [[NSUserDefaults standardUserDefaults] boolForKey:productIdentifier];
        if (productPurchased) {
            [_purchasedProductIdentifiers addObject:productIdentifier];
            NSLog(@"Previously purchased: %@", productIdentifier);
        } else {
            NSLog(@"Not purchased: %@", productIdentifier);
        }
    }

2013-03-10 17:45:13.609 COMPANY[1140:907] ProductIdentifier:  com.COMPANY.PRODUCTIDENTIFIER
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Value: (null)
2013-03-10 17:45:13.612 COMPANY[1140:907] Defaults Bool: 0
2013-03-10 17:45:13.611 COMPANY[1140:907] Defaults Object: (null)   
2013-03-10 17:45:13.611 COMPANY[1140:907] Static Key: 1

问题是您使用了

valueForKey:

而不是

objectForKey:

valueForKey

具有不同的语义（键值编码），尤其是与带有点的键一起使用时

更改此项：

[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]

为此：

[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]

它应该可以工作。

问题是您使用了

valueForKey:

而不是

objectForKey:

valueForKey

具有不同的语义（键值编码），尤其是与带有点的键一起使用时

更改此项：

[[NSUserDefaults standardUserDefaults] valueForKey:productIdentifier]

为此：

[[NSUserDefaults standardUserDefaults] objectForKey:productIdentifier]

它应该可以工作。

问题是所使用的NSSet中的产品标识符有前导空格，所以它从来不是直接匹配。

是否使用了

[[NSUserDefaults standardUserDefaults]synchronize]

保存值之后？如果您在保存后立即访问保存的值，您可能会发现有必要进行<代码>同步。-在应用程序运行时，同步将不会有助于解决问题。它仅适用于在应用程序外部持久化值，即使在应用程序外部，通常也没有必要。@Rog除了在

applicationIdentinterbackground:

app delegate方法中之外，不需要调用

synchronize

。是的，在设置值后（在购买完成并验证后）调用synchronize。正如我所说，问题不是保存价值。将所有NSUserDefaults显示为dictionaryRepresentation时，会清楚地保存该值。保存值后是否使用了

[[NSUserDefaults standardUserDefaults]synchronize]

？如果您在保存后立即访问保存的值，您可能会发现有必要进行<代码>同步。-在应用程序运行时，同步将不会有助于解决问题。它仅适用于在应用程序外部持久化值，即使在应用程序外部，通常也没有必要。@Rog除了在

applicationIdentinterbackground:

app delegate方法中之外，不需要调用

synchronize

。是的，在设置值后（在购买完成并验证后）调用synchronize。正如我所说，问题不是保存价值。将所有NSUserDefaults作为dictionaryRepresentation吐出时，该值会被清楚地保存。您是否在调试器中运行该应用程序？您是否通过调试器终止应用程序，再次运行，并发现缺少该值？这是正常的，因为如果您执行这些操作，

NSUserDefaults

可能还没有同步到磁盘，关闭应用程序可以防止出现这种情况。在应用程序代理的

ApplicationIdentinterBackground:

方法中添加对

[[NSUserDefaults standardUserDefaults]synchronize]

的调用。现在，请确保在使用调试器终止应用程序之前将其发送到后台。不要在模拟器和设备上使用具有相同结果的应用程序（即使在删除并重新运行应用程序之后）。我刚刚发现，使用静态字符串调用“boolForKey”返回正确的结果。但是记录'productIdentifier'NSString与正确的密钥完全匹配（我刚刚将它从日志复制并粘贴到静态密钥测试中）。请参阅以上发布中的更新。您是否正在使用“最近使用的应用”列表终止应用并重新启动？如果是的话，那是同一个问题。添加我提到的代码。从日志输出来看，问题很明显（但不明显）。

productIdentifier

变量有一些前导空格。将日志更改为：

NSLog（@“ProductIdentifier:'%@'，ProductIdentifier）。注意%@
周围添加的引号。然后您将看到空间。您是否在调试器中运行应用程序？您是否通过调试器终止应用程序，再次运行，并发现缺少该值？这是正常的，因为如果您执行这些操作，NSUserDefaults
可能还没有同步到磁盘，关闭应用程序可以防止出现这种情况。在应用程序代理的ApplicationIdentinterBackground:
方法中添加对[[NSUserDefaults standardUserDefaults]synchronize]
的调用。现在，请确保在使用调试器终止应用程序之前将其发送到后台。不要在模拟器和设备上使用具有相同结果的应用程序（即使在删除并重新运行应用程序之后）。我刚刚发现，使用静态字符串调用“boolForKey”返回正确的结果。但是记录'productIdentifier'NSString与正确的密钥完全匹配（我刚刚将它从日志复制并粘贴到静态密钥测试中）。请参阅以上发布中的更新。您是否正在使用“最近使用的应用”列表终止应用并重新启动？如果是的话，那是同一个问题。添加代码