如何在NSString中正确编码Unicode字符? [英] How do I properly encode Unicode characters in my NSString?
问题描述
我创建了许多字符串,将它们连接成CSV格式,然后将字符串作为附件发送电子邮件。
I create a number of strings, concatenate them together into CSV format, and then email the string as an attachment.
当这些字符串仅包含ASCII字符时,将生成CSV文件并通过电子邮件发送。当我包含非ASCII字符时,结果字符串变得格式错误,并且未正确创建CSV文件。 (电子邮件视图显示附件,但不会发送。)
When these strings contain only ASCII characters, the CSV file is built and emailed properly. When I include non-ASCII characters, the result string becomes malformed and the CSV file is not created properly. (The email view shows an attachment, but it is not sent.)
例如,这有效:
uncle bill's house of pancakes
但这不是(请注意卷曲撇号):
But this doesn't (note the curly apostrophe):
uncle bill’s house of pancakes
问题
如何正确创建和编码最终字符串,以便包含所有有效的unicode字符和结果字符串是否正确形成?
Question
How do I create and encode the final string properly so that all valid unicode characters are included and the result string is formed properly?
-
字符串是通过UITextField创建,然后写入并从核心数据存储读取。
The strings are created via a UITextField and then are written to and then read from a Core Data store.
这表明问题在于初始创建和编码字符串: NSString unicode编码问题
This suggests that the problem lies in the initial creation and encoding of the string: NSString unicode encoding problem
我不想这样做: 从objective-c中的NSString中删除非ASCII字符
I don't want to have to do this: remove non ASCII characters from NSString in objective-c
编写字符串并从数据存储中读取数据。字符串在应用程序的表视图中正确显示(单独)。只有在为电子邮件附件连接字符串时才会出现此问题。
The strings are written and read to/from the data store fine. The strings display properly (individually) in the app's table views. The problem only manifests when concatenating the strings together for the email attachment.
我将我的字符串连接在一起如下:
I concatenate my strings together like this:
[reportString appendFormat:@"%@,", category];
[reportString appendFormat:@"%@,", client];
[reportString appendFormat:@"%@\n", detail];
etc.
用无聊的引号替换卷曲引号使其有效,但我不知道想要这样做:
Replacing curly quotes with boring quotes makes it work, but I don't want to do it this way:
- (NSMutableString *)cleanString:(NSString *)activity {
NSString *temp1 = [activity stringByReplacingOccurrencesOfString:@"’" withString:@"'"];
NSString *temp2 = [temp1 stringByReplacingOccurrencesOfString:@"‘" withString:@"'"];
NSString *temp3 = [temp2 stringByReplacingOccurrencesOfString:@""" withString:@"\""];
NSString *temp4 = [temp3 stringByReplacingOccurrencesOfString:@""" withString:@"\""];
return [NSMutableString temp4];
}
修改:
电子邮件是已发送:
The email is sent:
NSString *attachment = [self formatReportCSV];
[picker addAttachmentData:[attachment dataUsingEncoding:NSStringEncodingConversionAllowLossy] mimeType:nil fileName:@"MyCSVFile.csv"];
其中 formatReportCSV
是连接和返回csv字符串。
where formatReportCSV
is the function that concatenates and returns the csv string.
推荐答案
您似乎遇到了字符串编码问题。如果没有看到你的核心数据模型是什么样的,我认为这个问题归结为下面代码重现的问题。
You seem to be running across a string encoding issue. Without seeing what your Core Data model looks like, I'd assume the issue boils down to the issue reproduced by the code below.
NSString *string1 = @"Uncle bill’s house of pancakes.";
NSString *string2 = @" Appended with some garbage's stuff.";
NSMutableString *mutableString = [NSMutableString stringWithString: string1];
[mutableString appendString: string2];
NSLog(@"We got: %@", mutableString);
// We got: Uncle bill’s house of pancakes. Appended with some garbage's stuff.
NSData *storedVersion = [mutableString dataUsingEncoding: NSStringEncodingConversionAllowLossy];
NSString *restoredString = [[NSString alloc] initWithData: storedVersion encoding: NSStringEncodingConversionAllowLossy];
NSLog(@"Restored string with NSStringEncodingConversionAllowLossy: %@", restoredString);
// Restored string with NSStringEncodingConversionAllowLossy:
storedVersion = [mutableString dataUsingEncoding: NSUTF8StringEncoding];
restoredString = [[NSString alloc] initWithData: storedVersion encoding: NSUTF8StringEncoding];
NSLog(@"Restored string with UTF8: %@", restoredString);
// Restored string with UTF8: Uncle bill’s house of pancakes. Appended with some garbage's stuff.
注意第一个字符串(使用ASCII编码)无法处理非ASCII的存在character(如果你使用 dataUsingEncoding:allowsLossyConversion:
,第二个参数是 YES
)。
Note how the first string (encoded using ASCII) couldn't handle the presence of the non-ASCII character (it can if you use dataUsingEncoding:allowsLossyConversion:
with the second parameter being YES
).
此代码应解决问题:
NSString *attachment = [self formatReportCSV];
[picker addAttachmentData:[attachment dataUsingEncoding: NSUTF8StringEncoding] mimeType:nil fileName:@"MyCSVFile.csv"];
注意:如果你需要处理非UTF8,你可能需要使用UTF16字符串编码之一像日语这样的语言。
Note: you may need to use one of the UTF16 string encodings if you need to handle non-UTF8 languages like Japanese.
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