为什么 NSNumber 类没有正确地将我的 NSString 对象转换为 long long？
我正在尝试将 NSString 对象转换为具有相同数值的 NSNumber 。当我使用此语句创建 NSString 对象时...
NSString *songID = [localNotif.userInfo objectForKey:@"SongID"];
var songID 包含字符串值 @"10359537395704663785"。当我尝试使用语句将其转换为 NSNumber 对象时...
NSNumber *songIDNumber = [NSNumber numberWithLongLong:[songID longLongValue]];
var songIDNumber 包含错误的 9223372036854775807 值
我做错了什么？还值得注意的是，有时此代码确实可以工作并生成正确的 NSNumber 值，但大多数时候它会失败，如上所示。
预先感谢您的帮助！
更新：天哪，我喜欢这个网站！感谢 unbeli 和 carl，我能够使用更新的代码来修复它，从 NSString 转换为 NSNumber...
unsigned long long ullvalue = strtoull([songID UTF8String], NULL, 0);
NSNumber *songIDNumber = [NSNumber numberWithUnsignedLongLong:ullvalue];
I'm trying to convert an NSString object to an NSNumber with the same numerical value. When I create the NSString object using this statement...
NSString *songID = [localNotif.userInfo objectForKey:@"SongID"];
the var songID contains the string value @"10359537395704663785". and when I attempt to convert it to an NSNumber object using the statement...
NSNumber *songIDNumber = [NSNumber numberWithLongLong:[songID longLongValue]];
the var songIDNumber contains the wrong value of 9223372036854775807
What am I doing wrong? It might also be worth noting that sometimes this code does work and produce the correct NSNumber value, but most of the time it fails as shown above.
Thanks in advance for your help!
UPDATE: God I love this site! Thanks to unbeli and carl, I was able to fix it using the updated code for converting from the NSString to the NSNumber...
unsigned long long ullvalue = strtoull([songID UTF8String], NULL, 0);
NSNumber *songIDNumber = [NSNumber numberWithUnsignedLongLong:ullvalue];
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longLongValue在溢出的情况下返回LLONG_MAX，而LLONG_MAX正是您得到的，9223372036854775807。您值根本不适合long long尝试使用 NSDecimalNumber 代替。
longLongValuereturnsLLONG_MAXin case of overflow, andLLONG_MAXis exactly what you get, 9223372036854775807. You value simply does not fit inlong longTry using NSDecimalNumber instead.
9223372036854775807十进制是0x7FFFFFFFFFFFFFFF十六进制。您的号码是10359537395704663785，对于long long来说太大并且溢出。来自 NSString 文档：9223372036854775807decimal is0x7FFFFFFFFFFFFFFFin hex. Your number is10359537395704663785, which is too large for along longand overflows. From the NSString documentation: