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

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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<NSString *> *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 plain copy
//  
//  YXError.h  
//  CustomYXError  
//  
//  Copyright (c) 2014年 Y.X. All rights reserved.  
//  
  
#import <Foundation/Foundation.h>  
  
// 自行添加错误码  
typedef enum : NSUInteger {  
  Crash     = -10000,  
  DisConnect,  
  Unknow,  
} YXErrorCode;  
  
@interface YXError : NSObject  
  
+ (NSError *)errorCode:(YXErrorCode)code userInfo:(NSDictionary *)dic;  
+ (NSString *)transformCodeToStringInfo:(YXErrorCode)code;  
  
@end  

[objc] view plain copy
//  
//  YXError.m  
//  CustomYXError  
//  
//  Copyright (c) 2014年 Y.X. All rights reserved.  
//  
  
#import "YXError.h"  
  
static NSDictionary *errorDictionary = nil;  
  
@implementation YXError  
  
+ (void)initialize  
{  
    if (self == [YXError class])  
    {  
        errorDictionary = \  
        @{  
          /* code        :        errorWithDomain */  
          /* ==================================== */  
            
          @(Crash)       :        @"Crash",  
          @(DisConnect)  :        @"DisConnect",  
          @(Unknow)      :        @"Unknow",  
            
          /* ==================================== */  
          };  
    }  
}  
  
+ (NSError *)errorCode:(YXErrorCode)code userInfo:(NSDictionary *)dic  
{  
    return [NSError errorWithDomain:errorDictionary[@(code)]  
                               code:code  
                           userInfo:dic];  
}  
  
+ (NSString *)transformCodeToStringInfo:(YXErrorCode)code  
{  
    return errorDictionary[@(code)];  
}  
  
@end  

以下是使用的代码：

[objc] view plain copy
//  
//  AppDelegate.m  
//  NSError  
//  
//  Copyright (c) 2014年 YouXianMing. All rights reserved.  
//  
  
#import "AppDelegate.h"  
#import "YXError.h"  
  
@implementation AppDelegate  
  
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions  
{  
    // 定制一个NSError  
    NSError *error = [YXError errorCode:Crash  
      userInfo:nil];  
    NSLog(@"%@", error);  
      
    // 翻译一个NSError（将code值翻译成字符串）  
    NSLog(@"%@", [YXError transformCodeToStringInfo:-10000]);  
      
    return YES;  
}  
  
@end 

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

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