ios - "If"语句之谜

Question

我有一个 if 例程，它将一个值与其他两个值进行比较(使用 || 运算符)，如果语句的计算结果为 YES，则值 firstActivity.stopTime 应该从 null 更改为当前时间 [NSDate date]。

然而，它似乎评估为 NO，导致没有变化，即使我的 NSLog 读数(和我自己的观察)似乎确认它必须评估为 YES。

代码如下:

-(void) compareActivity
{
    NSManagedObjectContext *localContext = [NSManagedObjectContext MR_contextForCurrentThread];
    TimedActivity *firstActivity = [TimedActivity MR_findFirstOrderedByAttribute:@"startTime" ascending:NO];

    NSLog(@"1 Currently timed activity is %@",firstActivity.name);
    NSLog(@"2 thisSpec.activityOfInterest is %@",self.thisSpec.activityOfInterest);
    NSLog(@"3 Currently timed activity stopTime is %@",firstActivity.stopTime);
    NSLog(@"4 thisSpec.benchmarkActivity is %@",self.thisSpec.benchmarkActivity);

    if (firstActivity.name == self.thisSpec.activityOfInterest || firstActivity.name == self.thisSpec.benchmarkActivity)
    {
        firstActivity.stopTime = [NSDate date];
        [localContext MR_saveToPersistentStoreAndWait];
        NSLog(@"5 Currently timed activity stopTime is %@",firstActivity.stopTime);
    }
    NSLog(@"6 Currently timed activity stopTime is %@",firstActivity.stopTime);
}

这是控制台的读数:

2014-04-28 22:15:06.588 WMDGx[5683:a0b] 1 Currently timed activity is Test 1
2014-04-28 22:15:06.588 WMDGx[5683:a0b] 2 thisSpec.activityOfInterest is Test 1
2014-04-28 22:15:06.589 WMDGx[5683:a0b] 3 Currently timed activity stopTime is (null)
2014-04-28 22:15:06.589 WMDGx[5683:a0b] 4 thisSpec.benchmarkActivity is Test 2
2014-04-28 22:15:06.589 WMDGx[5683:a0b] 6 Currently timed activity stopTime is (null)

有什么想法或建议吗？

谢谢!

更新:

我这样更新了我的代码:

if ([firstActivity.name isEqualToString:self.thisSpec.activityOfInterest] || [firstActivity.name isEqualToString:self.thisSpec.benchmarkActivity])
{
    firstActivity.stopTime = [NSDate date];
    [localContext MR_saveToPersistentStoreAndWait];
    NSLog(@"5 Currently timed activity stopTime is %@",firstActivity.stopTime);
}

现在它完美运行了!有趣的是，我以前曾经遇到过同样的问题，并且实际上尝试过更改代码，但这次我显然做错了什么，导致我认为这是错误的方法。

非常感谢!

Answer 1

你不能使用==来比较对象指针，你需要使用isEqual:比较对象

[firstActivity.name isEqual: self.thisSpec.activityOfInterest] || [firstActivity.name isEqual: self.thisSpec.benchmarkActivity]

如果它们是NSString，你可以使用isEqualToString: