Question

I have in my code an array of custom objects.

i want to write this array in a file on the documents folder. in this answer iPhone – archiving array of custom objects i saw that i need to implement this methods:

- (void)encodeWithCoder:(NSCoder *)aCoder;
- (id)initWithCoder:(NSCoder *)aDecoder;

so i implemented them:

- (void)encodeWithCoder:(NSCoder *)encoder {
  [encoder encodeObject:self.data forKey:@"data"];
  [encoder encodeObject:self.nome forKey:@"nome"];
  [encoder encodeObject:self.celular forKey:@"celular"];
  [encoder encodeObject:self.endereco forKey:@"endereco"];
  [encoder encodeObject:self.horaConclusao forKey:@"horaConclusao"];
  [encoder encodeObject:self.horaAtendimento forKey:@"horaAtendimento"];
}

- (id)initWithCoder:(NSCoder *)decoder {
  self = [super init];
  if (self) {
    self.data = [decoder decodeObjectForKey:@"data"];
    self.nome = [decoder decodeObjectForKey:@"nome"];
    self.celular = [decoder decodeObjectForKey:@"celular"];
    self.endereco = [decoder decodeObjectForKey:@"endereco"];
    self.horaConclusao = [decoder decodeObjectForKey:@"horaConclusao"];
    self.horaAtendimento = [decoder decodeObjectForKey:@"horaAtendimento"];
  }

  return self;
}

and in my code i write using this method:

this code is to remove old files

-(NSString *) plistHistoryFile {
  NSError *error;
  NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  NSString *documentsDirectory = [paths objectAtIndex:0];
  NSString *path = [documentsDirectory stringByAppendingPathComponent:[nameFile stringByAppendingPathExtension:@"plist"]];

  NSFileManager *filemgr = [NSFileManager defaultManager];
  if ([filemgr fileExistsAtPath:path]) {
    [filemgr removeItemAtPath:path error:&error];
  }

  return path;
}

and i call the write in this method:

-(void) writeArrayToHistoryFile:(NSArray *) array {
  NSString *path = [self plistHistoryFile];
  NSLog(@"%@", path);

  if ([array writeToFile:path atomically:NO]) {
    NSLog(@"YES");
  } else {
    NSLog(@"NO");
  }
}

but my response on the log is always NO, what am i doing wrong?

Answer 1

You need to find out what the error is, but you can’t get the error using -[NSArray writeToFile:atomically:]. Instead, write the file this way:

NSError *error;

NSData *data = [NSPropertyListSerialization dataWithPropertyList:array
    format: NSPropertyListBinaryFormat_v1_0 options:0 error:&error];
if (!data) {
    NSLog(@"failed to convert array to data: %@", error);
    return;
}

if (![data writeToFile:path options:NSDataWritingAtomic error:&error]) {
    NSLog(@"failed to write data to file: %@", error);
    return;
}

NSLog(@"wrote data successfully");