NSMutableArray addObject： - [__ NSArrayI addObject：]：发送到实例的无法识别的选择器 [英] NSMutableArray addObject: -[__NSArrayI addObject:]: unrecognized selector sent to instance

问题描述

我试图从周日初始化我的NSMutableArray 100种方式，并且NOTHING正在为我工​​作。我尝试将它设置为等于新分配和初始化的NSMutableArray，只是分配，初始化变量本身，我能想到的每个组合，并且总是相同的结果。

I have tried to initialize my NSMutableArray 100 ways from Sunday, and NOTHING is working for me. I tried setting it equal to a newly allocated and initialized NSMutableArray, just allocating, initializing the variable by itself, every combination I could think of and always the same result.

这里是代码：

Object.h

NSMutableArray *array;

@property (copy) NSMutableArray *array;

Object.m

@synthesize array;

if ( self.array ) {
    [self.array addObject:anObject];
}
else {
    self.array = [NSMutableArray arrayWithObjects:anObject, nil];
}

注意：在调试中，anObject在执行时不是nil。 。

NOTE: In debug "anObject" is NOT nil at time of execution...

我已经测试了anObject，它是初始化的工作正常，但是当我尝试addObject：to self.array时，我不断收到以下错误。

I have tested anObject and it isThe initialization works just fine, but I keep getting the error below when I try to addObject: to self.array.

2010-07-10 11：52：55.499 MyApp [4347：1807] - [__ NSArrayI addObject：]：无法识别的选择器发送到实例0x184480

2010-07-10 11:52:55.499 MyApp[4347:1807] -[__NSArrayI addObject:]: unrecognized selector sent to instance 0x184480

2010-07-10 11：52：55.508 MyApp [4347：1807] ***因未捕获的异常而终止应用
'NSInvalidArgumentException'，原因：' - [ __NSArrayI addObject：]：无法识别的选择器发送到实例0x184480'

2010-07-10 11:52:55.508 MyApp[4347:1807] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayI addObject:]: unrecognized selector sent to instance 0x184480'

有没有人知道出了什么问题？

Does anyone have any idea what's going wrong?

推荐答案

我想向Georg Fritzsche致敬。我最终需要使用（复制）而不是（保留），如果没有他的输入，我就不知道该怎么做。

I would like to tip my hat to Georg Fritzsche. I did end up needing to use (copy) instead of (retain), and I would not have known what to do without his input.

//@property (copy) NSMutableArray *array;
@property (nonatomic, copy) NSMutableArray *array; //overridden method is non-atomic as it is coded and should be reflected here.

如果你想在可变对象上使用（复制），你必须覆盖setter方法跟随...

If you wish to use (copy) on a mutable object you must override the "setter" method as follows...

- (void)setArray:(NSArray *)newArray {

    if ( array != newArray ) { 
        [array release];
        array = [newArray mutableCopy];
//      [array retain]; // unnecessary as noted by Georg Fritzsche
    }

    return;
}

注意：您将收到编译器警告：不兼容的Objective-C类型初始化' struct NSArray *'，expected'truct NSMutableArray *'我选择将newArray参数声明为（NSArray *），因为您可以灵活地将任何数组传递并正确复制到您的（NSMutableArray *）变量。如果你想将newArray参数声明为（NSMutableArray *），你仍然需要保留mutableCopy方法以获得你想要的结果。

NOTE: You will get a compiler warning: Incompatible Objective-C types initializing 'struct NSArray *', expected 'struct NSMutableArray *' I chose to declare the newArray parameter as an (NSArray *), because you are given the flexibility to have any array passed and correctly copied to your (NSMutableArray *) variable. If you wish to declare the newArray parameter as an (NSMutableArray *) you will still need to leave the mutableCopy method in place to get your desired results.

欢呼来到Georg！
Z @ K！

Cheers to Georg! Z@K!

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