Error while writing data to a file in iphone - iphone

Question

in my application, i have placed an empty
myFile.txt
when i have internet connection , i get json data from internet and save the json string in it with following code
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"myFile" ofType:#"txt"];
[myString writeToFile:filePath automatically:YES encoding:NSUTF... error:nil];
//now while retrieving it when no internet connection
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"myFile" ofType:#"txt"];
NSString *myString = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF.. error:nil];
now myString returns with #""... why i am not been able to write data?
Best Regards

Answer 1

Whatever you want to do is not possible (or at least strongly discouraged) to update files in the app bundle.
If you’re downloading files and want to store them on the device you should use the Documents directory. You can get the path to this directory with:
- (NSString *)getDocumentsDirectory {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
return [paths objectAtIndex:0];
}

Answer 2

First check weather the contents are getting written to file. You can view the file in xcode.
What i suggest is when you run the app create this empty file. Then you can Read and write to that file easily.
Try Using Below code:
NSError* error = nil;
NSString* jsonFileName = [NSString stringWithFormat:#"myfile"];
NSString* jsonPath = [[NSBundle mainBundle] pathForResource:jsonFileName
ofType:#"txt"];
NSString* jsonString = [NSString stringWithContentsOfFile:jsonPath
encoding:NSUTF8StringEncoding error:&error];
Documents directory:
Write to file
NSArray *paths = NSSearchPathForDirectoriesInDomains
(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
//make a file name to write the data to using the documents directory:
NSString *fileName = [NSString stringWithFormat:#"%#/textfile.txt",
documentsDirectory];
//create content - four lines of text
NSString *content = #"One\nTwo\nThree\nFour\nFive";
//save content to the documents directory
[content writeToFile:fileName
atomically:NO
encoding:NSStringEncodingConversionAllowLossy
error:nil];
Display content:
NSArray *paths = NSSearchPathForDirectoriesInDomains
(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
//make a file name to write the data to using the documents directory:
NSString *fileName = [NSString stringWithFormat:#"%#/textfile.txt",
documentsDirectory];
NSString *content = [[NSString alloc] initWithContentsOfFile:fileName
usedEncoding:nil
error:nil];