Question

For example: I have a mutable array of BOOLs(or [NSNumber numberWithBool:TRUE]; ). and then I want to change, for example the first value in this array to FALSE.

[array addObject:[NSNumber numberWithBool:TRUE]];
[array objectAtIndex:0] ???

我知道,完成这项任务的方法非常奇怪。

[array replaceObjectAtIndex:0 withObject:[NSNumber numberWithBool:FALSE]];

Yes, this fully satisfies me, but I am looking for another way, that is more simple than this. Something like [[array objectAtIndex:0] setBoolValue:FALSE]; for example, imagine, if I had UIButton instead of BOOLs: [[array objectAtIndex:0] setHidden:TRUE]; or this is only dreams?

提前感谢!

Answer 1

The best way to do this is

[array replaceObjectAtIndex:0 withObject:[NSNumber numberWithBool:FALSE]];

原因是[array ObjectAtIndex:0] 返回NSNumber,与您有一系列的不同。 UIButtons, which would re a UIButton Object that You can act on. 由于您重新获得<代码>NSNumber,你可以做任何事情做。 NSNumber <>/code> direct since it doesn t have the methods sent to the NSNumber。

Answer 2

没有任何东西阻止你向一个阵列中的物体发送突变电文,但NSNumber根本无法变。因此,你不得不用不同的标语取代标的。它与阵列或语言毫不相干,你可以改变国家独立党。

Answer 3

Something to understand here: Arrays are simple collections of pointers to object. Hence, you can easily to things like
((UIButton*)[array objectAtIndex:0]).hidden=TRUE;
Modifying the object is possible and often done. But exchanging one object for another one, you need to use Replacement techniques as you pointed out. However, simpler objects are, as said above by @Chuck, simply not mutable (like NSNumber).

并请指出,我前面的法典在稳定方面是可怕的。你们怎么肯定知道,它把你从你们的魔术帽(即阵列)中夺走。

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