20160126深入淺出obc知識點整理

標籤：

1.錯誤域Error Domain

NSMachErrorDomain:系統核心錯誤

NSPOSIXErrorDomain:系統錯誤

NSOSStatusErrorDomian:MacOS9之前的錯誤或者Carbon架構錯誤

NSCocoaErrorDomain:cocoa架構錯誤

 

2.本地化錯誤描述

(1)NSUnderlyingErrorKey

NSDictionary *userInfo = [error userInfo];

NSString *errorDesc = nil;

 

//檢查有沒有"NSUnderlyingErrorKey"可供使用

if(userInfo && [userInfo objectForKey:NSUnderlyingErrorKey]){

     NSError *underlyingError = [userInfo objectForKey:NSUnderlyingErrorKey];

     if(underlyingError){

          errorDesc = [underlyingError localizedDescription];

     }

     else{

          errorDesc = [error localizedDescription];

     }

}

else{

    errorDesc = [error localizedDescription];

}

 

(2)localized Description

NSError *errorInfo = nil;

//假設在作業系統的根目錄上放一個"test.rtf"檔案,strTest拿到@"/test.rf"的內容

NSString *strTest = [NSString stringWithContentsOfFile:@"/test.rf"

                                             encoding:NSUTF8StringEncoding

                                             ettor:&errorInfo];

 

if(!strTest){

    if(!errorInfo){

       NSLog(@"An error occurred: %@" , [errorInfo localizedDescription]);

    }else{

       NSLog(@"An unknow error occurred" );

    }

}

 

3.輸出當前的函數

%s __FUNCTION__

 

4.單例

share*****

default*****

 

5.ARC

weak和strong代替assign.retain.copy

 

6.KVC

valueForKeyPath  取

setValue: forkey:  設定

 

7.KVO

[self addObserver:self

        forKeyPath:@"datasrc"

        options:*****

        context:@"testContent"];

 

 

 

 

 

 

 

 

 

 

 

 

 

 

20160126深入淺出obc知識點整理