问题描述
在我开始之前,这里有一些背景知识,基本上我们希望将 UDP 响应与存储在我们应用程序的 Parse 数据库中的字符串进行比较.这个问题是我似乎无法让 isEqualToString 函数将字符串视为相等.这是我现在运行的代码,我尝试了一些在其他问题中看到的变通方法,但它仍然不起作用.
A little background here before I get started, basically we are looking to compare a UDP response with a string stored in Parse's database for our app. This issue is that I can't seem to get the strings to be considered equal by the isEqualToString function. Here's the code I have running now, I have tried a few work-arounds I've seen in other questions but it still doesn't work.
- (BOOL) onUdpSocket:(AsyncUdpSocket *)sock didReceiveData:(NSData *)data withTag:(long)tag fromHost:(NSString *)host port:(UInt16)port
{
if(tag == TAG_SINGLE_GRILL)
{
NSString *grillId = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
if(grillId.length > 11)
{
grillId = [grillId substringToIndex:11];
}
grillId = [NSString stringWithFormat:@"%@", grillId];
if([grillId hasPrefix:@"GMG"])
{
for(int i = 0; i < [parseGrills count]; i++)
{
NSString *parseGrillId = [[parseGrills objectAtIndex:i] grillId];
parseGrillId = [NSString stringWithFormat:@"%@", parseGrillId];
//If we match the id, add it to found grills
if([grillId isEqualToString:parseGrillId])
{
//do stuff
}
}
}
NSLog(@"Grill ID : %@", grillId);
}
return TRUE;
}
parseGrills 是一个带有非常基本的 Grill 对象的 NSMutableArray,我使用合成作为属性,否则 .m 文件基本上是空的.
parseGrills is an NSMutableArray with a very basic Grill object, I use synthesize for the properties, otherwise the .m file is essentially empty.
#import <Foundation/Foundation.h>
@interface Grill : NSObject
@property (nonatomic) NSString* grillId;
@property (nonatomic) NSString* ipAddress;
@end
这是调试器返回 false 后的屏幕截图
Here's a screen shot of the debugger after it returns false
任何帮助将不胜感激.谢谢.
Any help would be greatly appreciated. Thanks.
推荐答案
我猜他们是不同的编码.
I guess that they are of different encoding.
我运行了这个实验,看到如果编码不同,它会返回NO
.因此,尝试使用以下代码将 parseGrillId
转换为 utf8
.
I have run this experiment and see that if the encoding is different, it will return NO
. So, try converting parseGrillId
to utf8
with the code below.
NSString *s1 = [NSString stringWithCString:"HELLO123" encoding:NSUTF8StringEncoding];
NSString *s2 = [NSString stringWithCString:"HELLO123" encoding:NSUTF16StringEncoding];
NSString *s3 = [NSString stringWithUTF8String:s2.UTF8String];
if ([s1 isEqualToString:s2]) {
NSLog(@"s1 == s2");
}
if ([s1 isEqualToString:s3]) {
NSLog(@"s1 == s3");
}
将打印s1 == s3
.
这篇关于isEqualToString 总是返回 False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!