我正在尝试更新 NSMutableDictionary 但我得到了
mutating method sent to immutable object
错误。 itemMutableArray 是 NSMutableArray 的实例，它包含 NSMutableDictionary 的实例。请帮忙。
for(NSMutableDictionary *dict in itemMutableArray){
for (NSString *key in [dict allKeys]) {
NSString *kv = [dict valueForKey:key];
if([kv isEqualToString:[NSString stringWithFormat:@"%@%d",@"FIELD_",k]]) {
[dict setValue:field.text forKey:@"Value"];
}
}
}
异常:
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[__NSCFDictionary setObject:forKey:]: mutating method sent to immutable object'
*** First throw call stack:
(
0 CoreFoundation 0x000000010cb07f35 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x000000010c574bb7 objc_exception_throw + 45
2 CoreFoundation 0x000000010cb07e6d +[NSException raise:format:] + 205
3 CoreFoundation 0x000000010ca3e8a3 -[__NSCFDictionary setObject:forKey:] + 99
4 MobileWalletBanking 0x0000000109e41c62 -[MyViewController validateConnectionFields] + 6178
5 MobileWalletBanking 0x0000000109e402f1 -[MyViewController validateInputFields] + 2065
6 MobileWalletBanking 0x0000000109e42291 -[MyViewController performBillPayment:] + 97
7 UIKit 0x000000010abdb8be -[UIApplication sendAction:to:from:forEvent:] + 75
8 UIKit 0x000000010ace2410 -[UIControl _sendActionsForEvents:withEvent:] + 467
9 UIKit 0x000000010ace17df -[UIControl touchesEnded:withEvent:] + 522
10 UIKit 0x000000010af88540 _UIGestureRecognizerUpdate + 9487
11 UIKit 0x000000010ac20ff6 -[UIWindow _sendGesturesForEvent:] + 1041
12 UIKit 0x000000010ac21c23 -[UIWindow sendEvent:] + 667
13 UIKit 0x000000010abee9b1 -[UIApplication sendEvent:] + 246
14 UIKit 0x000000010abfba7d _UIApplicationHandleEventFromQueueEvent + 17370
15 UIKit 0x000000010abd7103 _UIApplicationHandleEventQueue + 1961
16 CoreFoundation 0x000000010ca3d551 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
17 CoreFoundation 0x000000010ca3341d __CFRunLoopDoSources0 + 269
18 CoreFoundation 0x000000010ca32a54 __CFRunLoopRun + 868
19 CoreFoundation 0x000000010ca32486 CFRunLoopRunSpecific + 470
20 GraphicsServices 0x000000010e14f9f0 GSEventRunModal + 161
21 UIKit 0x000000010abda420 UIApplicationMain + 1282
22 MobileWalletBanking 0x0000000109db5733 main + 115
23 libdyld.dylib 0x000000010dca4145 start + 1
)
最佳答案
你的字典显然不是 NSMutableDictionary 的实例，否则你不会得到那个错误。
调试法则:你以为你知道的都是错的。
将指针声明为 NSMutableDictionary* 不会使项成为可变字典。
检查将字典添加到数组的代码，并检查添加不可变字典的位置。
顺便说一句。阅读 valueForKey 和 setValueForKey 的文档。然后阅读objectForKey和setObjectForKey的文档。看完它们，你真的要用valueForKey吗？您是否了解它有时会做一些可能根本不是您期望的事情，尤其是当您无法控制按键时？
关于ios - 发送到不可变对象(immutable对象)的变异方法 - [__NSCFDictionary setObject :forKey:]，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33752998/