Objective-C如何列出所有可用的编码

Question

In Java I can get all the available encodings with this code:

SortedMap<String, Charset> availableCharsets = Charset.availableCharsets();
Vector allEncodes = new Vector();
for (Map.Entry<String, Charset> entry : availableCharsets.entrySet()) {
            allEncodes.add(entry.getKey());
}

Then, I can read any file with any encode I want:

Reader in = new InputStreamReader(new FileInputStream(aPath), allEncodes.get(0) );

So, is there any idea how to implement this in Objective-C

Answer 1

const NSStringEncoding* encodingArray = [NSString availableStringEncodings];

Answer 2

This is more or less translation of your code from Java. You need also to complete the code checking readingError variable. Of course, central point is avaiableStringEncodings static message.

  NSMutableArray *arrayOfEncodings = [[NSMutableArray alloc] init];

  const NSStringEncoding *encodings = [NSString availableStringEncodings];
  while (*encodings != 0){
    [arrayOfEncodings addObject:[NSNumber numberWithInt:*encodings]];
    encodings++;
  }

  NSError *readingError = nil;
  NSString yourPath = @"some path you want";
  NSData *data = [[NSData alloc] initWithContentsOfFile:yourPath    options:NSDataReadingUncached error:&readingError];

  NSStringEncoding firstEncoding = (NSStringEncoding) [((NSNumber *) [arrayOfEncodings objectAtIndex:0]) intValue];

  NSString *myString = [[NSString alloc] initWithData:data encoding:firstEncoding];