Question

Friend it just general question .

How can write and retrieve the data on to the file .And how can make this file in .csv format.

For example i am retrieve data like that

NSString *coords = [[[NSString alloc] initWithFormat:@"%f,%f\n",longitude,latitude] autorelease];
[locations addObject:coords];

Than how can write this data on to the file in .csv format.

And than How can i retrieve this data

Answer 1

To write csv

NSString *coords = [[[NSString alloc] initWithFormat:@"%f,%f\n",longitude,latitude] autorelease];

NSData *csvData =  [coords dataUsingEncoding:NSUTF8StringEncoding];

NSArray *UsrDocPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *DocsDir = [UsrDocPath objectAtIndex:0];
    NSString *csvPath = [DocsDir stringByAppendingPathComponent:@"coords.csv"];

    //This is upto your logic that do you want to remove existant csv file or not
    BOOL success = [FileManager fileExistsAtPath:csvPath];
    if(success){
        [FileManager removeItemAtPath:csvPath error:&error];
    }

    [csvData writeToFile:csvPath atomically:YES];

To read from file

NSData *csvData = [NSData dataWithContentsOfFile:csvPath];
NSString *strCSV = [[NSString alloc]initWithData:csvData encoding:NSUTF8StringEncoding];

Hope it helps