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[__NSCFDictionary setObject:forK

[__NSCFDictionary setObject:forK

作者: 听歌么 | 来源:发表于2017-05-11 14:07 被阅读155次

使用NSMutableDictionary时,如果操作不当,有可能会引起程序崩溃。示例代码:

NSString *result = @"{\"username\”:\”aaa\”,\"phone\":\"15666666666\",\"bankcount\":\"98765432112345678\"}";  
NSData *data = [result dataUsingEncoding:NSUTF8StringEncoding];  
NSMutableDictionary *info = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];  
if (info) {  
    NSString *username = [Utils UrlDecode: info[@"username"]];  
    [info  setObject:username forKey:@"username"];  
}  

执行上述代码后报错:

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

出错原因在于:

[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];

返回的结果是immutable对象,不能直接对immutable进行赋值操作,否则会报错。

修改后代码:

NSString *result = @"{\"username\”:\”aaa\”,\"phone\":\"15666666666\",\"bankcount\":\"98765432112345678\"}";  
NSData *data = [result dataUsingEncoding:NSUTF8StringEncoding];  
//----将immutable转换为mutable----  
NSMutableDictionary *temp = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];  
NSMutableDictionary *info = [NSMutableDictionary dictionaryWithDictionary:temp];  
//----------------------  
if (info) {  
    NSString *username = [Utils UrlDecode:info[@"username"]];  
    [info  setObject:username forKey:@"username"];  
} 
NSMutableDictionary *dic = [getDefaults valueForKey:@"loginInfo"];
[dic2  setObject:tf1.text forKey:@"phone"];

报错:

'-[__NSCFDictionary setObject:forKey:]: mutating method sent to immutable object

修改:

NSMutableDictionary *dic = (NSMutableDictionary *)[getDefaults valueForKey:@"loginInfo"];
NSMutableDictionary *dic2 = [NSMutableDictionary dictionaryWithDictionary:dic];
[dic2  setObject:tf1.text forKey:@"phone"];       

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