異常 'NSInvalidArgumentException'： - [__ NSArrayM objectForKey：]：無法識別的選擇發送到實例0x752c670

Question

我用sbjson解析JSON， 這是JSON的，我試圖解析：

{"R":"0","S":"","T":"","M":[{"C00":"2013-08-16 17:35:03"}]} 

，這是我的代碼：

NSString *response = [self post:@"9903" content:payload state:@""]; 
NSDictionary *dict = [response JSONValue]; 
NSString *result = [dict objectForKey:@"R"]; 
NSLog(@"result=%@",result); 
if ([@"0" isEqualToString:result]) { 
    NSDictionary *msg = [dict objectForKey:@"M"]; 
    NSString *C00 = [msg objectForKey:@"C00"];//here the exception Statement 
    NSString *tokenString = [NSString stringWithFormat:@"%@",C00]; 
    NSLog(@"tokenString%@",tokenString); 
    return tokenString; 
}else { 
    return nil; 
} 

異常日誌：

2013-08-16 17:45:44.902 VEP[4731:c07] -[__NSArrayM objectForKey:]: unrecognized selector sent to instance 0x7250300 
2013-08-16 17:45:44.903 VEP[4731:c07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayM objectForKey:]: unrecognized selector sent to instance 0x7250300' 

什麼錯了嗎？謝謝你的幫助！

Answer 1

因爲您的密鑰'M:'包含字典數組不僅字典。因此，將它寫爲，

NSDictionary *msg = [[dict objectForKey:@"M"] objectAtIndex:0];