How to read/write file with iOS, in simulator as well as on device?

Question

As I need to read a file when my app is launched and write it sometimes while using it, I tried to reach it with :

NSString *dataFile = [[NSBundle mainBundle         


        

Answer 1

#import "ViewController.h"

@interface ViewController ()

@property (strong, nonatomic) IBOutlet UITextView *txtWriteText;
@property (strong, nonatomic) IBOutlet UIButton *btnWriteFile;
@property (strong, nonatomic) IBOutlet UIButton *btnReadFile;
@property (strong, nonatomic) IBOutlet UILabel *lblReadText;

- (IBAction)btnWriteFileTouched:(id)sender;
- (IBAction)btnReadFileTouched:(id)sender;

@property NSFileManager *filemgr;
@property NSString *docsDir;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    _filemgr =[NSFileManager defaultManager];
    NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
    _docsDir = dirPaths[0];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

- (IBAction)btnWriteFileTouched:(id)sender {
    NSString *filePath = [_docsDir stringByAppendingPathComponent: @"texfile.txt"];
    NSData *databuffer = [@"PREFIX: " dataUsingEncoding: NSASCIIStringEncoding];
    [_filemgr createFileAtPath: filePath contents: databuffer attributes:nil];

    NSFileHandle *file = [NSFileHandle fileHandleForWritingAtPath:                                filePath];
    if (file == nil){
        NSLog(@"Failed to open file");
        return;
    }

    NSMutableData *data = [NSMutableData dataWithData:[_txtWriteText.text dataUsingEncoding:NSASCIIStringEncoding]];

    [file seekToEndOfFile];
    [file writeData: data];
    [file closeFile];
}

- (IBAction)btnReadFileTouched:(id)sender {
    NSString *filePath = [_docsDir stringByAppendingPathComponent: @"texfile.txt"];
    NSData *databuffer;
    NSFileHandle *file = [NSFileHandle fileHandleForReadingAtPath: filePath];
    if (file == nil){
        NSLog(@"Failed to open file");
        return;
    }

    databuffer = [file readDataToEndOfFile];
    [file closeFile];

    NSString *datastring = [[NSString alloc] initWithData: databuffer encoding:NSASCIIStringEncoding];
    _lblReadText.text = datastring;
}

@end