Iphone 这些奇怪的东西是什么；流氓角色'；在我的字符串末尾？

我有一个文本文件（songlist.txt），我的应用程序从服务器检索并存储在本地。当我尝试在我的应用程序中使用文件的内容时，我得到了意想不到的结果。当我研究这个问题时，我发现文本文件的NSString内容末尾有时会出现奇怪的字符。

为什么这些奇怪的人物在这里？（以下是我的资料来源）：

字符串末尾的奇怪字符示例：

1） 我
2） upp†
3） mul†
4） ID

//文本文件（songlist.txt）的确切内容

歌曲1.mp3
第二首歌。mp3
歌曲三。mp3
歌曲4.mp3
歌曲5.mp3

//Downloading Songlist from the internet, Saving it to Documents folder
-(void)downloadSongList
{
    NSString *songlistString;

    NSString *URLString_list = @"http://et.bicdoss.com/app/songlist.txt";
    NSURL *URL_list = [NSURL URLWithString:[URLString_list stringByAddingPercentEscapesUsingEncoding:                           NSASCIIStringEncoding]];

    // Get Data of Contents (for Write to Disk)
    NSData *songData = [NSData dataWithContentsOfURL:URL_list];

    if(songData == nil) {

        NSLog(@"SONGLIST.TXT NOT DOWNLOADED");

    }else{

    // Write Songlist.txt to disk
    NSString *filePath = [[self documentsDirectory] stringByAppendingPathComponent:@"Music/songlist.txt"];
    [songData writeToFile:filePath atomically:YES];
       NSLog(@"SONGLIST.TXT DOWNLOADED");
    }

}

// Retrieve songlist.txt from local documents folder
-(NSString*)getLocalSongList
{
NSData *textFileData = [NSData dataWithContentsOfFile:[[self documentsDirectory] stringByAppendingPathComponent:@"Music/songlist.txt"]];
NSString *textFileString = [NSString stringWithUTF8String:[textFileData bytes]];

return textFileString;          
}

//Create NSMutableArray of contents of songlist.txt (seperated by linebreaks)

...
NSMutableArray *files_catalog;
    files_catalog = [[NSMutableArray alloc] init];
    [files_catalog addObjectsFromArray:[[self getLocalSongList] componentsSeparatedByString: @"\n"]];
    [files_catalog retain];

    for(int a = 0; a<[files_catalog count]; a++){
        NSLog(@"Contents of Object %i (files_catalog) %@", a, [files_catalog objectAtIndex:a]);
/*

NOTE:
The above NSLog statement always gives strange output (note strange characters at the end of last filename:)

(output)
2010-02-02 21:22:27.145 SomeApp[19670:207] >>>>>>>>>>>>>>>>>>>> Cntnts of Objct 0 (files_catalog) Song One.mp3
2010-02-02 21:22:27.145 SomeApp[19670:207] >>>>>>>>>>>>>>>>>>>> Cntnts of Objct 1 (files_catalog) Song Two.mp3
2010-02-02 21:22:27.146 SomeApp[19670:207] >>>>>>>>>>>>>>>>>>>> Cntnts of Objct 2 (files_catalog) Song Three.mp3
2010-02-02 21:22:27.146 SomeApp[19670:207] >>>>>>>>>>>>>>>>>>>> Cntnts of Objct 3 (files_catalog) Song Four.mp3
2010-02-02 21:22:27.146 SomeApp[19670:207] >>>>>>>>>>>>>>>>>>>> Cntnts of Objct 4 (files_catalog) Song Five.mp3upp†


Some other examples of strange characters at the end were:

I
upp†
mul†
ID

*/
}

...

//从internet下载歌曲列表，并将其保存到Documents文件夹
-（作废）下载歌曲列表
{
NSString*songlistString；
NSString*URLString_list=@”http://et.bicdoss.com/app/songlist.txt";
NSURL*URL_list=[NSURL URLWithString:[URLString_list stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding]；
//获取内容的数据（用于写入磁盘）
NSData*songData=[NSData dataWithContentsOfURL:URL_list]；
if（songData==nil）{
NSLog（@“SONGLIST.TXT未下载”）；
}否则{
//将Songlist.txt写入磁盘
NSString*文件路径=[[self documents directory]stringByAppendingPathComponent:@“Music/songlist.txt”]；
[songData WriteFile:文件路径原子：是]；
NSLog（@“SONGLIST.TXT下载”）；
}
}
//从本地文档文件夹检索songlist.txt
-（NSString*）getLocalSongList
{
NSData*textFileData=[NSData dataWithContentsOfFile:[[self documents directory]stringByAppendingPathComponent:@“Music/songlist.txt”]；
NSString*textFileString=[NSString stringWithUTF8String:[textFileData bytes]]；
返回textFileString；
}
//创建songlist.txt内容的NSMutableArray（以换行符分隔）
...
NSMUTABLEARRY*文件目录；
文件_catalog=[[NSMutableArray alloc]init]；
[files_catalog addObjectsFromArray:[[self-getLocalSongList]组件由字符串分隔：@“\n”]；
[文件目录保留]；
对于（int a=0；a>>>>>>>>>>>>>>>>>>>>>>>>>>Objct 0（文件目录）Song One.mp3的CNNTs
2010-02-02 21:22:27.145 SomeApp[19670:207]>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
2010-02-02 21:22:27.146 SomeApp[19670:207]>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
2010-02-02 21:22:27.146 SomeApp[19670:207]>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
2010-02-02 21:22:27.146 SomeApp[19670:207]>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>Objct 4（文件目录）Song Five.mp3upp†
结尾处的其他一些奇怪字符示例如下：
我
upp†
mul†
身份证件
*/
}
...

导入时，编码似乎出错。请尝试使用stringWithContentsOfFile:encoding:error:method

[NSString stringWithContentsOfFile:[[self documentsDirectory] stringByAppendingPathComponent:@"Music/songlist.txt"] encoding:NSUTF8StringEncoding error:nil];

此外，它跳过了NSData步骤