Objective C - Create text file to read and write line by line in Cocoa

Question

I building a Mac app,I have 2 problem:

I want to create a text file to read and write data on it. I don't know how to crate a text file to read and write data. Is it use struct?

I want to create a XML file to read and write data on it. Can I create a struct for XML?

Do you have suggestion? Thanks in advance

Take a look at http://stackoverflow.com/a/3711079/944634 – Parag Bafna Jul 22 '13 at 10:35 — Parag Bafna, Jul 22 '13 at 10:35

score 32 · Accepted Answer · answered Jul 22 '13 at 03:58

32

Well, to create a file, just use

[[NSFileManager defaultManager] createFileAtPath:@"Your/Path" contents:nil attributes:nil];

This creates an empty file, which you can write to or read from. To write text (or XML), just use NSString's writeToFile:atomically:encoding:error: method like this

NSString *str = //Your text or XML
[str writeToFile:"Your/Path" atomically:YES encoding:NSUTF8StringEncoding error:nil];

To read from a file, just make an NSString with the contents of that file

NSString *contents = [NSString stringWithContentsOfFile:@"Your/Path"];

or, if it does not contain a string, get an NSData object from the file

NSData *contents = [NSData dataWithContentsOfFile:@"Your/Path"];

answered Jul 22 '13 at 03:58

Chris Loonam

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? What do you mean by that? – Chris Loonam Jul 22 '13 at 05:13
I have a question: Can I use struct to save data on files? – HTKT611 Jul 22 '13 at 05:51
You can use a struct to save information on a file, but if you're using objective c I would recommend using a class, for example one named File, and then defining the properties of a file in that class (file name, size, contents, etc.). – Chris Loonam Jul 22 '13 at 06:10
NSString *str = //Your text or XML [str writeToFile:"Your/Path" atomically:YES encoding:NSUTF8StringEncoding error:nil]; Can use NSMutablearray instead of NSString ? – HTKT611 Jul 22 '13 at 07:40
You can, but that would write the data as a plist, which is a form of XML. – Chris Loonam Jul 22 '13 at 12:21
How can I do if i want add at first line to XML file. – HTKT611 Jul 23 '13 at 10:59
Make a string containing that and write it to the file. – Chris Loonam Jul 23 '13 at 15:13
And how to read from XML file? Is it same read from text file? – HTKT611 Jul 24 '13 at 01:46
Thanks but if I create XML file same text file, it can not create schema XML? Example: abc then end line and have a space add. And if have long XML,when read node, it difficult. Can you show me an optimized suggestion? Thanks much – HTKT611 Jul 24 '13 at 02:06
It can, you just have to insert the appropriate newlines (`\n`) and spaces. – Chris Loonam Jul 24 '13 at 02:08
You'd have to look it up. I don't know how. – Chris Loonam Jul 24 '13 at 02:17
The "NSString *contents = [NSString stringWithContentsOfFile:@"Your/Path"];" was first deprecated in iOS 2.0 – jungledev Feb 25 '16 at 18:27

score 6 · Answer 2 · answered Jun 17 '14 at 09:50

/**************************main.m******************************
    NS FILE HANDLE READ & WRITE
    reading and writing in same file
    Created by abdulsathar on 6/16/14.
***************************************************************/

#import <Foundation/Foundation.h>
int main(int argc, const char * argv[])
{
   @autoreleasepool  //ARC
    {
        NSFileHandle *file;
        //object for File Handle
        NSError *error;
        //crearing error object for string with file contents format
        NSMutableData *writingdatatofile;
        //create mutable object for ns data
        NSString *filePath=[NSString stringWithFormat:@"/Users/chandrakumar/Documents/abdul/doc.txt"];
        //telling about File Path for Reading for easy of access
        file = [NSFileHandle fileHandleForReadingAtPath:@"/Users/chandrakumar/Documents/abdul/doc.txt"];
        //assign file path directory
            if (file == nil) //check file exist or not
                NSLog(@"Failed to open file");
        NSString *getfileContents = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:&error];
        //access file contents with out ns handle method
            if (error) //check error flag for file present or not
                NSLog(@"Error reading file: %@", error.localizedDescription);
        NSLog(@"contents: %@", getfileContents);
        //display file contents in main file
        NSArray *listArray = [getfileContents componentsSeparatedByString:@"\n"];
        //caluculate list of line present in files
        NSLog(@"items = %ld", [listArray count]);
        const char *writingchar = "how are you";
        writingdatatofile = [NSMutableData dataWithBytes:writingchar length:strlen(writingchar)];
        //convert string format into ns mutable data format
        file = [NSFileHandle fileHandleForUpdatingAtPath: @"/Users/chandrakumar/Documents/abdul/new.txt"];
        //set writing path to file
            if (file == nil) //check file present or not in file
                NSLog(@"Failed to open file");
        [file seekToFileOffset: 6];
        //object pointer initialy points the offset as 6 position in file
        [file writeData: writingdatatofile];
        //writing data to new file
        [file closeFile];
        //close the file
    }
    return 0;`enter code here`
}

/***********************************OUTPUT********************************************

 2014-06-17 14:55:39.695 storage[4075:303] contents: hello how are you my dearservice

*************************************************************************************/

Objective C - Create text file to read and write line by line in Cocoa

2 Answers2