在使用可变数组过程中遇到*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[__NSCFDictionary setObject:forKey:]: mutating method sent to immutable object'问题

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[__NSCFDictionary setObject:forKey:]: mutating method sent to immutable object'

初始代码

NSMutableDictionary *dataDict=[[NSMutableDictionary alloc]init];

dataDict=responseObject[@"post"];

NSString *str=dataDict[@"content"];
str=[self handleStringWithString:str];               
[dataDict setObject:str forKey:@"content"];

这是由于我把不可变的字典赋到可变字典，只要修改为

dataDict=  [NSMutableDictionary dictionaryWithDictionary:responseObject[@"post"]];

就可以了。