如何从NSURL的末尾删除3个字符？

Question

我的第一个问题！我已经能够编写大部分这个RSS阅读器而无需获得帮助（通过大量的搜索，通过计算器！），但我在这里难倒了。

NSString *urlbase = [[NSString alloc] initWithFormat:[links3 objectAtIndex:indexPath.row]]; 
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:urlbase]]; 
NSCharacterSet *whitespaces = [NSCharacterSet whitespaceCharacterSet]; 
NSPredicate *noEmptyStrings = [NSPredicate predicateWithFormat:@"SELF != ''"]; 

NSArray *parts = [urlbase componentsSeparatedByCharactersInSet:whitespaces]; 
NSArray *filteredArray = [parts filteredArrayUsingPredicate:noEmptyStrings]; 
urlbase = [filteredArray componentsJoinedByString:@" "]; 

NSLog(@"%@ %i" , urlbase, 4353); 
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:urlbase]]; 

links3数组是带字符串的NSMutableArray。前几行完美地消除了从数组开始的每个字符串的空间，这些字符串存储在'urlbase'中，因此当它们出来时它们看起来很好。当我们的NSLog urlbase，我们看到：

http://www.feedzilla.com/r/D7E6204FEDBFE541314B997AAB5D2DF9CBA2EFEE 

但是，当我们使用：[[UIApplication sharedApplication] openURL:[NSURL URLWithString:urlbase]]

我们看到：http://www.feedzilla.com/r/D7E6204FEDBFE541314B997AAB5D2DF9CBA2EFEE%0A

我该如何解决这个问题？我能否以某种方式移除这些尾巴元素？谢谢！

工作代码：

NSMutableArray *links3 = [[NSMutableArray alloc] init]; 
RSSAppDelegate *appDelegate = (RSSAppDelegate *)[[UIApplication sharedApplication] delegate]; 
links3 = appDelegate.links; 
NSLog(@"%@ %i", [links3 objectAtIndex:indexPath.row], 3453); 
NSString *urlbase = [[NSString alloc] initWithFormat:[links3 objectAtIndex:indexPath.row]]; 
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:urlbase]]; 
NSCharacterSet *whitespaces = [NSCharacterSet whitespaceCharacterSet]; 
NSPredicate *noEmptyStrings = [NSPredicate predicateWithFormat:@"SELF != ''"]; 

NSArray *parts = [urlbase componentsSeparatedByCharactersInSet:whitespaces]; 
NSArray *filteredArray = [parts filteredArrayUsingPredicate:noEmptyStrings]; 
urlbase = [filteredArray componentsJoinedByString:@" "]; 

NSLog(@"%@ %i" , urlbase, 4353); 


NSLog(@"%@ %i" , urlbase, 345346); 
NSString* fixed = [urlbase stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]]; 

NSURL *hellothere = [NSURL URLWithString:fixed]; 
NSLog(@"%@ %i", hellothere, 54); 


    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:fixed]]; 

嘿，我并没有说这是漂亮。感谢Diederik Hoogenboom！

Answer 1

试试这个：

[urlbase stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]] 

你的URL字符串的最后一部分是换行。