iOS NSError详解 NSError错误code对照表 自定义、定制NSError 一看就懂

一、NSError是系统错误信息类

//两种初始化方法:其中,domain 不能为空 dict可以为空

  • (instancetype)initWithDomain:(NSErrorDomain)domain code:(NSInteger)code userInfo:(nullable NSDictionary *)dict;
  • (instancetype)errorWithDomain:(NSErrorDomain)domain code:(NSInteger)code userInfo:(nullable NSDictionary *)dict;

@property (readonly, copy) NSErrorDomain domain;//错误域

错误域主要有四个,对于Carbon框架的Error,归于OSStatus domain(NSOSStatusErrorDomain),对于POSIX error,归于NSPOSIXErrorDomain,而对于我们的iOS开发,一般使用NSCocoaErrorDomain。NSError.h定义了四个domain

{

// Predefined domain for errors from most AppKit and Foundation APIs.
FOUNDATION_EXPORT NSErrorDomain const NSCocoaErrorDomain;

// Other predefined domains; value of "code" will correspond to preexisting values in these domains.
FOUNDATION_EXPORT NSErrorDomain const NSPOSIXErrorDomain;
FOUNDATION_EXPORT NSErrorDomain const NSOSStatusErrorDomain;
FOUNDATION_EXPORT NSErrorDomain const NSMachErrorDomain;

}

@property (readonly) NSInteger code;//错误代码

@property (readonly, copy) NSDictionary *userInfo;//错误信息

@property (readonly, copy) NSString *localizedDescription;//获取本地化描述

@property (nullable, readonly, copy) NSString *localizedFailureReason;//获取失败原因

@property (nullable, readonly, copy) NSString *localizedRecoverySuggestion;//获取恢复建议

@property (nullable, readonly, copy) NSArray *localizedRecoveryOptions;本地恢复建议

@property (nullable, readonly, strong) id recoveryAttempter;

@property (nullable, readonly, copy) NSString *helpAnchor;

预定义的userinfo键名

NSString *const NSUnderlyingErrorKey;//推荐的标准方式,通用键
NSString *const NSLocalizedDescriptionKey; // 详细描述键
NSString *const NSLocalizedFailureReasonErrorKey; // 失败原因键
NSString *const NSLocalizedRecoverySuggestionErrorKey; //恢复建议键
NSString *const NSLocalizedRecoveryOptionsErrorKey; // 恢复选项键

//其他键

NSString *const NSRecoveryAttempterErrorKey;
NSString *const NSHelpAnchorErrorKey;
NSString *const NSStringEncodingErrorKey ;
NSString *const NSURLErrorKey;
NSString *const NSFilePathErrorKey;

用法示例:

NSDictionary *userInfo1 = [NSDictionary dictionaryWithObjectsAndKeys:@"由于文件不存在,无法打开", NSLocalizedDescriptionKey, @"失败原因:文件不存在", NSLocalizedFailureReasonErrorKey, @"恢复建议:请创建该文件",NSLocalizedRecoverySuggestionErrorKey,nil];

NSError *error = [[NSError alloc] initWithDomain:NSCocoaErrorDomain code:4 userInfo:userInfo1];//此处code是4,对照下面对照表4代表文件不存在。userinfo传userinfo1 查看自定义打印。userinfo传nil,查看本地化描述。

NSLog(@"========%@",[error localizedDescription]);
NSLog(@"========%@",[error localizedFailureReason]);
NSLog(@"========%@",[error localizedRecoverySuggestion]);

二、NSError错误code对照表

Foundation Constants Reference
NSError Codes

NSError codes in the Cocoa error domain.

enum {
NSFileNoSuchFileError = 4,
NSFileLockingError = 255,
NSFileReadUnknownError = 256,
NSFileReadNoPermissionError = 257,
NSFileReadInvalidFileNameError = 258,
NSFileReadCorruptFileError = 259,
NSFileReadNoSuchFileError = 260,
NSFileReadInapplicableStringEncodingError = 261,
NSFileReadUnsupportedSchemeError = 262,
NSFileReadTooLargeError = 263,
NSFileReadUnknownStringEncodingError = 264,
NSFileWriteUnknownError = 512,
NSFileWriteNoPermissionError = 513,
NSFileWriteInvalidFileNameError = 514,
NSFileWriteInapplicableStringEncodingError = 517,
NSFileWriteUnsupportedSchemeError = 518,
NSFileWriteOutOfSpaceError = 640,
NSFileWriteVolumeReadOnlyError = 642m
NSKeyValueValidationError = 1024,
NSFormattingError = 2048,
NSUserCancelledError = 3072,

NSFileErrorMinimum = 0,
NSFileErrorMaximum = 1023,
NSValidationErrorMinimum = 1024,
NSValidationErrorMaximum = 2047,
NSFormattingErrorMinimum = 2048,
NSFormattingErrorMaximum = 2559,

NSPropertyListReadCorruptError = 3840,
NSPropertyListReadUnknownVersionError = 3841,
NSPropertyListReadStreamError = 3842,
NSPropertyListWriteStreamError = 3851,
NSPropertyListErrorMinimum = 3840,
NSPropertyListErrorMaximum = 4095

NSExecutableErrorMinimum = 3584,
NSExecutableNotLoadableError = 3584,
NSExecutableArchitectureMismatchError = 3585,
NSExecutableRuntimeMismatchError = 3586,
NSExecutableLoadError = 3587,
NSExecutableLinkError = 3588,
NSExecutableErrorMaximum = 3839,

}
URL Loading System Error Codes

These values are returned as the error code property of an NSError object with the domain “NSURLErrorDomain”.

typedef enum
{
NSURLErrorUnknown = -1,
NSURLErrorCancelled = -999,
NSURLErrorBadURL = -1000,
NSURLErrorTimedOut = -1001,
NSURLErrorUnsupportedURL = -1002,
NSURLErrorCannotFindHost = -1003,
NSURLErrorCannotConnectToHost = -1004,
NSURLErrorDataLengthExceedsMaximum = -1103,
NSURLErrorNetworkConnectionLost = -1005,
NSURLErrorDNSLookupFailed = -1006,
NSURLErrorHTTPTooManyRedirects = -1007,
NSURLErrorResourceUnavailable = -1008,
NSURLErrorNotConnectedToInternet = -1009,
NSURLErrorRedirectToNonExistentLocation = -1010,
NSURLErrorBadServerResponse = -1011,
NSURLErrorUserCancelledAuthentication = -1012,
NSURLErrorUserAuthenticationRequired = -1013,
NSURLErrorZeroByteResource = -1014,
NSURLErrorCannotDecodeRawData = -1015,
NSURLErrorCannotDecodeContentData = -1016,
NSURLErrorCannotParseResponse = -1017,
NSURLErrorFileDoesNotExist = -1100,
NSURLErrorFileIsDirectory = -1101,
NSURLErrorNoPermissionsToReadFile = -1102,
NSURLErrorSecureConnectionFailed = -1200,
NSURLErrorServerCertificateHasBadDate = -1201,
NSURLErrorServerCertificateUntrusted = -1202,
NSURLErrorServerCertificateHasUnknownRoot = -1203,
NSURLErrorServerCertificateNotYetValid = -1204,
NSURLErrorClientCertificateRejected = -1205,
NSURLErrorClientCertificateRequired = -1206,
NSURLErrorCannotLoadFromNetwork = -2000,
NSURLErrorCannotCreateFile = -3000,
NSURLErrorCannotOpenFile = -3001,
NSURLErrorCannotCloseFile = -3002,
NSURLErrorCannotWriteToFile = -3003,
NSURLErrorCannotRemoveFile = -3004,
NSURLErrorCannotMoveFile = -3005,
NSURLErrorDownloadDecodingFailedMidStream = -3006,
NSURLErrorDownloadDecodingFailedToComplete = -3007
}

三、自定义NSError

系统的NSError是可以自己定制的,以下提供代码来实现并表示如何使用:

YXError.h 与 YXError.m

[objc] view plaincopy

  1. //

  2. // YXError.h

  3. // CustomYXError

  4. //

  5. // Copyright (c) 2014年 Y.X. All rights reserved.

  6. //

  7. import

  8. // 自行添加错误码

  9. typedef enum : NSUInteger {

  10. Crash = -10000,

  11. DisConnect,

  12. Unknow,

  13. } YXErrorCode;

  14. @interface YXError : NSObject

    • (NSError *)errorCode:(YXErrorCode)code userInfo:(NSDictionary *)dic;
    • (NSString *)transformCodeToStringInfo:(YXErrorCode)code;
  15. @end

[objc] view plaincopy

  1. //

  2. // YXError.m

  3. // CustomYXError

  4. //

  5. // Copyright (c) 2014年 Y.X. All rights reserved.

  6. //

  7. import "YXError.h"

  8. static NSDictionary *errorDictionary = nil;

  9. @implementation YXError

    • (void)initialize
  10. {

  11. if (self == [YXError class])

  12. {

  13. errorDictionary = \

  14. @{

  15. /* code : errorWithDomain */

  16. /* ==================================== */

  17. @(Crash) : @"Crash",

  18. @(DisConnect) : @"DisConnect",

  19. @(Unknow) : @"Unknow",

  20. /* ==================================== */

  21. };

  22. }

  23. }

    • (NSError *)errorCode:(YXErrorCode)code userInfo:(NSDictionary *)dic
  24. {

  25. return [NSError errorWithDomain:errorDictionary[@(code)]

  26. code:code

  27. userInfo:dic];

  28. }

    • (NSString *)transformCodeToStringInfo:(YXErrorCode)code
  29. {

  30. return errorDictionary[@(code)];

  31. }

  32. @end

以下是使用的代码:

[objc] view plaincopy

  1. import "AppDelegate.h"

  2. import "YXError.h"

  3. @implementation AppDelegate

    • (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
  4. {

  5. // 定制一个NSError

  6. NSError *error = [YXError errorCode:Crash

  7. userInfo:nil];

  8. NSLog(@"%@", error);

  9. // 翻译一个NSError(将code值翻译成字符串)

  10. NSLog(@"%@", [YXError transformCodeToStringInfo:-10000]);

  11. return YES;

  12. }

  13. @end

参考链接:https://blog.csdn.net/hdfqq188816190/article/details/52754943

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