没有命中if语句 [英] no hit on if-statement

问题描述

我想获得一个命中我的if语句。我从Core Data数据库获取qDiff（整数32），一切正常，除非得到一个命中的if语句：

  NSString * diff; 
 
 NSArray * fetchedObjects = [qContext executeFetchRequest：fetchRequest error：& error]; 
 for（NSManagedObject * info in fetchedObjects）{
 NSLog（@idQ：％@，[info valueForKey：@idQ]）; 
 NSLog（@qDiff：％@，[info valueForKey：@qDiff]）; //<<<<<<<打印正确的数字
 
 diff = [info valueForKey：@qDiff]; 
 NSLog（@diff：％@，diff）;如果（[diff isEqual：@1]）NSLog（@EASY），则打印正确的数字
 
 ; 
 
 // if（[diff isEqualToString：@2]）NSLog（@MEDIUM）; 
 // if（[[info valueForKey：@qDiff] isEqualToString：@3]）NSLog（@HARD）; //<<<<<<<试过这个第一个
 
 
 NSLog（@question：％@，[info valueForKey：@question]）; 
} 
 [fetchRequest release]; 
 

我一直在尝试不同的if语句，但它不触发（打印NSLog）。

任何人可以给我一个提示？

========= UPDATE ==========

我改为：

  if（[diff isEqualToString：@1]）NSLog 简单）; 
  

得到以下结果：

2010-12-12 15：39：49.321 XX_v2 [2950：207] idQ：0

2010-12-12 15：39：49.321 XX_v2 [2950：207] qDiff： 1

2010-12-12 15：39：49.322 XX_v2 [2950：207] diff：1

2010-12-12 15：39：49.322 XX_v2 [2950：207] - [_ PFCachedNumber isEqualToString：]：无法识别的选择器发送到实例0xa0f9008

2010-12-12 15：39：49.324 XX_v2 [2950：207] 由于未捕获异常终止应用程序'NSInvalidArgumentException'，reason：' - [_ PFCachedNumber isEqualToString：]：unrecognized selector sent to instance 0xa0f9008'

=== ======= UPDATE＃2 =======

尝试：

  if（[diff isEqual：@1]）NSLog（@EASY）; 
  

输出没有差异：

2010-12-12 15：55：57.381 XX_v2 [3151：207] idQ：0

2010-12-12 15：55：57.382 XX_v2 [3151：207] qDiff： 1

2010-12-12 15：55：57.382 XX_v2 [3151：207] diff：1

2010-12-12 15：55：57.382 XX_v2 [3151：207]问题：你想要新的吗？

但是，在调试器中我发现：

'diff'变量不是CFString

==== ==== UPDATE＃3 ========

更新上面的代码以显示'diff'的定义。

======== UPDATE＃4 ========

我终于用这个语句解决了这个问题：

  if [[info valueForKey：@qDiff] intValue] = 1）NSLog（@EASY）; 
  

解决方案

您正在处理 qDiff 作为NSString，而Core Data将其保存为整数32，并将其显示为NSNumber。尝试这样：

  if（[diff isEqualToNumber：[NSNumber numberWithInt：1]]）NSLog（@EASY）; 
  

或：

  if（[diff intValue] == 1）NSLog（@EASY）; 
  

I am trying to get a hit on my if-statement. I fetch qDiff (integer32) from the Core Data db and everything works except get a hit on the if-statements:

NSString *diff;

NSArray *fetchedObjects = [qContext executeFetchRequest:fetchRequest error:&error];
for (NSManagedObject *info in fetchedObjects) {
    NSLog(@"idQ: %@", [info valueForKey:@"idQ"]);
    NSLog(@"qDiff: %@", [info valueForKey:@"qDiff"]); //<<<<<<<<<Print correct number

    diff = [info valueForKey:@"qDiff"];
    NSLog(@"diff: %@", diff);       //<<<<<<<<<Print correct number

    if ([diff isEqual:@"1"]) NSLog(@"EASY");

    //if ([diff isEqualToString: @"2"]) NSLog(@"MEDIUM");
    //if ([[info valueForKey:@"qDiff"] isEqualToString: @"3"]) NSLog(@"HARD"); //<<<<<<tried this first


    NSLog(@"question: %@", [info valueForKey:@"question"]);
}        
[fetchRequest release];      

I have been trying different If-statements but it does not trigger (print the NSLog).

Anyone that can give me a hint?

=========UPDATE==========

I changed to:

if ([diff isEqualToString:@"1"]) NSLog(@"EASY");

And got the following:

2010-12-12 15:39:49.321 XX_v2[2950:207] idQ: 0
2010-12-12 15:39:49.321 XX_v2[2950:207] qDiff: 1
2010-12-12 15:39:49.322 XX_v2[2950:207] diff: 1
2010-12-12 15:39:49.322 XX_v2[2950:207] -[_PFCachedNumber isEqualToString:]: unrecognized selector sent to instance 0xa0f9008
2010-12-12 15:39:49.324 XX_v2[2950:207] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[_PFCachedNumber isEqualToString:]: unrecognized selector sent to instance 0xa0f9008'

==========UPDATE #2=======

Did try:

if ([diff isEqual:@"1"]) NSLog(@"EASY");

no difference in output:

2010-12-12 15:55:57.381 XX_v2[3151:207] idQ: 0
2010-12-12 15:55:57.382 XX_v2[3151:207] qDiff: 1
2010-12-12 15:55:57.382 XX_v2[3151:207] diff: 1
2010-12-12 15:55:57.382 XX_v2[3151:207] question: Do you want a new?

However, in the debugger i found:

'diff' "Variable not a CFString"

========UPDATE#3========

Updated the code above to show definition of 'diff'.

========UPDATE#4========

I did finally solve the problem with this statement:

if ([[info valueForKey:@"qDiff"] intValue] == 1) NSLog(@"EASY");

解决方案

You are treating qDiff as an NSString while Core Data saves it as an integer32 and exposes it as an NSNumber. Try this:

if ([diff isEqualToNumber:[NSNumber numberWithInt:1]]) NSLog(@"EASY");

Or this:

if ([diff intValue] == 1) NSLog(@"EASY");

这篇关于没有命中if语句的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！