iOS開發-mutating method sent to immutable object錯誤

iOS開發-mutating method sent to immutable object錯誤

今天幹活的時候,遇到了這樣一個問題..

實在是太粗心了。mark下,

 

2014-01-05 11:44:34.762 softwareApp[1435:c07] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '*** -[JKDictionary setObject:forKey:]: mutating method sent to immutable object'

*** First throw call stack:

(0x285a012 0x1e48e7e 0x2859deb 0x36b96 0x18610ef 0x6c8df 0xabd61 0xac0f8 0x1e5c6b0 0x1bc3b 0x1e5c6b0 0x1888765 0x27ddf3f 0x27dd96f 0x2800734 0x27fff44 0x27ffe1b 0x2a927e3 0x2a92668 0xd8cffc 0x2d5d 0x2551725 0x1)

libc++abi.dylib: terminate called throwing an exception

Program ended with exit code: 0

 

這是報錯處的代碼。

 

[cpp] 

1. NSDictionary *jsonData = [resultDic objectAtIndex:i];
2. NSArray *eachLines = [[jsonData objectForKey:@newsTime] componentsSeparatedByString:@.];
3. [jsonData setValue:[eachLines objectAtIndex:0] forKey:@newsTime];
4. [testArr addObject:jsonData];
   
   

    

   …現在想想都覺得丟人阿。

    

   看reason:後面的異常說明：意思是我把一個可變數對應的方法讓一個不可變數來調用

   mutating　method（可變數對應的方法）:是那些在建立後可以被更改的變數所擁有的method，比如NSMutableArray,NSMutableDictionary 等

   immutable object(不可改變的變數):就是那些被建立後不能被改變的變數:比如　NSArray　NSDictionary等

    

   修改後，正常運行。

    

    

   [cpp]
   1. NSMutableDictionary *jsonData = [resultDic objectAtIndex:i];
   2. NSArray *eachLines = [[jsonData objectForKey:@newsTime] componentsSeparatedByString:@.];
   3. [jsonData setValue:[eachLines objectAtIndex:0] forKey:@newsTime];
   4. [testArr addObject:jsonData];