Question

我想知道如果我在这个if语句中做错了......

我正在计算两个indexPaths，旧的一个和当前选择的一个如果它们不相等我想做其他明智的事情继续正常..

然而我的if语句总是被访问，即使它们是！= ..我做错了什么..我知道你可以检查IsEqual：这里有类似的东西！=？

继承我的代码和输出

NSLog(@"%@", modelIndexPath);
            NSLog(@"%@", oldCheckedIndexPath);
            NSLog(@"%@", indexPath);
            if (modelIndexPath != indexPath) {
                NSLog(@"Not Equal");
                NSLog(@" ");
            }

2012-01-19 16:09:06.521 Code[9907:207] (null)
2012-01-19 16:09:06.522 Code[9907:207] (null)
2012-01-19 16:09:06.523 Code[9907:207] <NSIndexPath 0xc2993e0> 2 indexes [9, 0]
2012-01-19 16:09:06.524 Code[9907:207] Not Equal
2012-01-19 16:09:06.525 Code[9907:207]  
2012-01-19 16:09:17.921 Code[9907:207] <NSIndexPath 0xc2993e0> 2 indexes [9, 0]
2012-01-19 16:09:17.922 Code[9907:207] <NSIndexPath 0xc2993e0> 2 indexes [9, 0]
2012-01-19 16:09:17.923 Code[9907:207] <NSIndexPath 0xc5b0c50> 2 indexes [9, 0]
2012-01-19 16:09:17.924 Code[9907:207] Not Equal
2012-01-19 16:09:17.925 Code[9907:207]  
2012-01-19 16:09:29.489 Code[9907:207] <NSIndexPath 0xc5b0c50> 2 indexes [9, 0]
2012-01-19 16:09:29.490 Code[9907:207] <NSIndexPath 0xc5b0c50> 2 indexes [9, 0]
2012-01-19 16:09:29.491 Code[9907:207] <NSIndexPath 0xc7886c0> 2 indexes [9, 2]
2012-01-19 16:09:29.491 Code[9907:207] Not Equal
2012-01-19 16:09:29.492 Code[9907:207]  
2012-01-19 16:09:34.945 Code[9907:207] <NSIndexPath 0xc7886c0> 2 indexes [9, 2]
2012-01-19 16:09:34.946 Code[9907:207] <NSIndexPath 0xc7886c0> 2 indexes [9, 2]
2012-01-19 16:09:34.946 Code[9907:207] <NSIndexPath 0xc89e780> 2 indexes [9, 2]
2012-01-19 16:09:34.947 Code[9907:207] Not Equal
2012-01-19 16:09:34.948 Code[9907:207]  
2012-01-19 16:09:37.601 Code[9907:207] <NSIndexPath 0xc89e780> 2 indexes [9, 2]
2012-01-19 16:09:37.602 Code[9907:207] <NSIndexPath 0xc89e780> 2 indexes [9, 2]
2012-01-19 16:09:37.602 Code[9907:207] <NSIndexPath 0xc94e480> 2 indexes [9, 1]
2012-01-19 16:09:37.603 Code[9907:207] Not Equal
2012-01-19 16:09:37.604 Code[9907:207]

更新

这是在你们的帮助下目前的事态

NSLog(@"%@", modelIndexPath);
            NSLog(@"%@", oldCheckedIndexPath);
            NSLog(@"%@", indexPath);

            if ( [modelIndexPath isEqual:indexPath] ) NSLog(@"hurray!");
            if ( ![modelIndexPath isEqual:indexPath] ) NSLog(@"bummer");
            NSLog(@" ");



2012-01-19 16:41:54.853 Code[11071:207] (null)
2012-01-19 16:41:54.854 Code[11071:207] (null)
2012-01-19 16:41:54.855 Code[11071:207] <NSIndexPath 0xc21f9a0> 2 indexes [9, 0]
2012-01-19 16:41:54.856 Code[11071:207] bummer
2012-01-19 16:41:54.856 Code[11071:207]  
2012-01-19 16:41:59.637 Code[11071:207] <NSIndexPath 0xc21f9a0> 2 indexes [9, 0]
2012-01-19 16:41:59.637 Code[11071:207] <NSIndexPath 0xc21f9a0> 2 indexes [9, 0]
2012-01-19 16:41:59.638 Code[11071:207] <NSIndexPath 0x6a73e10> 2 indexes [9, 0]
2012-01-19 16:41:59.639 Code[11071:207] hurray!
2012-01-19 16:41:59.639 Code[11071:207]  
2012-01-19 16:42:05.492 Code[11071:207] <NSIndexPath 0x6a73e10> 2 indexes [9, 0]
2012-01-19 16:42:05.493 Code[11071:207] <NSIndexPath 0x6a73e10> 2 indexes [9, 0]
2012-01-19 16:42:05.494 Code[11071:207] <NSIndexPath 0x6aae9d0> 2 indexes [9, 0]
2012-01-19 16:42:05.494 Code[11071:207] hurray!
2012-01-19 16:42:05.495 Code[11071:207]  
2012-01-19 16:42:10.901 Code[11071:207] <NSIndexPath 0x6aae9d0> 2 indexes [9, 0]
2012-01-19 16:42:10.902 Code[11071:207] <NSIndexPath 0x6aae9d0> 2 indexes [9, 0]
2012-01-19 16:42:10.902 Code[11071:207] <NSIndexPath 0xc625470> 2 indexes [9, 2]
2012-01-19 16:42:10.903 Code[11071:207] bummer

Answer 1

NSIndexPath是对象，使用

进行比较

if (![modelIndexPath isEqual:indexPath])

编辑：也许发布更多的代码，上面的代码应该没问题，或者你也可以做，（取决于你的需要）

int modelRow = [modelIndexPath row];
int indexRow = [indexPath row];

if (modelRow != indexRow)
{
    // Do something here
}

请注意，这只会根据您的需要生效！

Answer 2

那些NSIndexPath事物是对象，你正在比较它们的内存地址。换句话说，modelIndexPath和indexPath都是指针。（谷歌是你的朋友）

要比较这些对象，请使用：

if ( [modelIndexPath isEqual:indexPath] ) NSLog(@"hurray!");

或

if ( ![modelIndexPath isEqual:indexPath] ) NSLog(@"bummer");

测试不平等。

Answer 3

您正在比较实例地址。使用if (![modelIndexPath isEqual:indexPath]) { //...

Answer 4

使用isEqual:代替==

==表示两个引用是否指向同一个对象

isEqual:表示对象相等

if ([modelIndexPath isEqual: indexPath]) {
                NSLog(@"Not Equal");
                NSLog(@" ");
            }

如果语句没有正确使用indexpath

4 个答案: