如何使用NSRange和整数来简化我的代码？

Question

我刚刚开始学习Objective-C并制作了一个小指南针应用程序,当它落入一系列标题时会显示方向.它工作得很好,但我想知道是否有更简洁的方式来编写它NSRange.经过大量的研究,似乎NSRange更多地用于字符串函数而不是数字.

我尝试制作一个NSRange我的出发点的实例,使其更加简洁,我无法找到一个数字落在一个数字内的函数NSRange.

我在这里走在正确的轨道上,还是我让它变得比它需要的更冗长？

提前致谢..

这是我试图缩短代码的失败点:

// If heading falls within this range, then display "S" for south    
NSRange eastenRange = NSMakeRange (80, 100); 
NSRange southernRange = NSMakeRange (170, 190); 
etc...

这是我目前的代码(工作正常):

- (void)locationManager:(CLLocationManager *)manager 
    didUpdateHeading:(CLHeading *)newHeading
{
 // Define and display the heading
 NSNumber *theHeading = [NSNumber numberWithInt:[newHeading trueHeading]];
 [headingLabel setText:[NSString stringWithFormat:@"%@°", theHeading]];

 // Define the range of directions
 NSNumber *northLowerRange = [NSNumber numberWithInt:10];
 NSNumber *northUpperRange = [NSNumber numberWithInt:350];

 NSNumber *eastLowerRange = [NSNumber numberWithInt:80];
 NSNumber *eastUpperRange = [NSNumber numberWithInt:100];

 NSNumber *southLowerRange = [NSNumber numberWithInt:170];
 NSNumber *southUpperRange = [NSNumber numberWithInt:190];

 NSNumber *westLowerRange = [NSNumber numberWithInt:260];
 NSNumber *westUpperRange = [NSNumber numberWithInt:280];


 // If the heading falls within the correct ranges, then display the direction
 if ([northLowerRange compare:theHeading] == NSOrderedDescending || [northUpperRange compare:theHeading] == NSOrderedAscending)
  [directionLabel setText:@"N"];
 else if ([eastLowerRange compare:theHeading] == NSOrderedAscending && [eastUpperRange compare:theHeading] == NSOrderedDescending)
  [directionLabel setText:@"E"];
 else if ([southLowerRange compare:theHeading] == NSOrderedAscending && [southUpperRange compare:theHeading] == NSOrderedDescending)
  [directionLabel setText:@"S"];
 else if ([westLowerRange compare:theHeading] == NSOrderedAscending && [westUpperRange compare:theHeading] == NSOrderedDescending)
  [directionLabel setText:@"W"];
 else
  [directionLabel setText:@"-"];

}

Answer 1

迟到了,但以下会工作并利用我相信的范围:

NSRange easternRange = NSMakeRange (80, 20); 
NSRange southernRange = NSMakeRange (170, 20); 

NSInteger heading = 92;
if (NSLocationInRange(heading,easternRange)) {
  NSLog(@"Heading Easterly.");
} else if (NSLocationInRange(heading,southernRange)) {
  NSLog(@"Heading southerly.");
}

等等

Answer 2

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我是否让这个变得比需要的更冗长？

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是的。当你想要进行数值运算时，请避免使用 NSNumber。NSNumber 类的存在只是因为像 NSArray、NSDictionary 等 Objective-C 集合只能保存 Objective-C 对象。否则，您应该始终使用普通的intorNSInteger或CGFloat等double。

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 int heading = [newHeading trueHeading];\n headingLabel.text = [NSString stringWithFormat:@"%d\xc2\xb0", heading];\n\n if (10 < heading || heading > 350)\n    directionLabel.text = @"N";\n else if (80 < heading && heading < 100)\n    directionLabel.text = @"E";\n // and so on.\n

\n\n

您不需要使用 NSRange。

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