Read/write file in Documents directory problem - iphone

Question

I am trying to write a very basic text string to my documents directory and work from there to later save other files etc.
I am currently stuck with it not writing anything into my Documents directory
(In my viewDidLoad)
NSArray *pathArray = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)
NSString *documentsDirectory = [pathArray objectAtIndex:0];
NSString *textPath = [documentsDirectory stringByAppendingPathComponent:#"file1.txt"];
NSString *text = #"My cool text message";
[[NSFileManager defaultManager] createFileAtPath:textPath contents:nil attributes:nil];
[text writeToFile:textPath atomically:NO encoding:NSUTF8StringEncoding error:NULL];
NSLog(#"Text file data: %#",[[NSFileManager defaultManager] contentsAtPath:textPath]);
This is what gets printed out:
2011-06-27 19:04:43.485 MyApp[5731:707] Text file data: (null)
If I try this, it also prints out null:
NSLog(#"My Documents: %#", [[NSFileManager defaultManager] contentsOfDirectoryAtPath:documentsDirectory error:NULL]);
What have I missed or am I doing wrong while writing to this file?
Might it be something I need to change in my plist or some frameworks/imports needed?
Thanks
[EDIT]
I passed a NSError object through the writeToFile and got this error:
Error: Error Domain=NSCocoaErrorDomain Code=512 "The operation couldn’t be completed. (Cocoa error 512.)" UserInfo=0x12aa00 {NSFilePath=/var/mobile/Applications/887F4691-3B75-448F-9384-31EBF4E3B63E/Documents/file1.txt, NSUnderlyingError=0x14f6b0 "The operation couldn’t be completed. Not a directory"}
[EDIT 2]
This works fine on the simulator but not on my phone :/

Answer 1

Instead of using NSFileManager to get the contents of that file, try using NSString as such:
NSArray *pathArray = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)
NSString *documentsDirectory = [pathArray objectAtIndex:0];
NSString *textPath = [documentsDirectory stringByAppendingPathComponent:#"file1.txt"];
NSError *error = nil;
NSString *str = [NSString stringWithContentsOfFile:textPath encoding:NSUTF8StringEncoding error:&error];
if (error != nil) {
NSLog(#"There was an error: %#", [error description]);
} else {
NSLog(#"Text file data: %#", str);
}
Edit: Added error checking code.

Answer 2

How are you getting documentsDirectory?
You should be using something like this:
NSArray *pathArray = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)
NSString *documentsDirectory = [pathArray lastObject];

Answer 3

Put an NSLog statement after every line where you are setting a variable's value, so that you can inspect those values. This should help you quickly pinpoint where things start to go wrong.

Answer 4

The problem got solved by setting a non standard Bundle ID in die info.plist
I used the Bundle ID from iTunes Connect for this specific app. Now everything works perfectly.

Answer 5

You can also use NSFileHandle for writing data in file and save to document directory:
Create a variable of NSFileHandle
NSFileHandle *outputFileHandle;
use the prepareDataWrittenHandle function with passing file name in parameter with file extension
-(void)prepareDataWrittenHandle:(NSString *)filename
{
//Create Path of file in document directory.
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *outputFilePath = [documentsDirectory stringByAppendingPathComponent:filename];
//Check file with above name is already exits or not.
if ([[NSFileManager defaultManager] fileExistsAtPath:outputFilePath] == NO) {
NSLog(#"Create the new file at outputFilePath: %#", outputFilePath);
//Create file at path.
BOOL suc = [[NSFileManager defaultManager] createFileAtPath:outputFilePath
contents:nil
attributes:nil];
NSLog(#"Create file successful?: %u", suc);
}
outputFileHandle = [NSFileHandle fileHandleForWritingAtPath:outputFilePath];
}
then write the string value to file as:
//Create a file
[self prepareDataWrittenHandle:#"file1.txt"];
//String to save in file
NSString *text = #"My cool text message";
//Convert NSString to NSData to save data in file.
NSData* data = [text dataUsingEncoding:NSUTF8StringEncoding]
//Write NSData to file
[_outputFileHandle writeData:data];
//close the file if written complete
[_outputFileHandle closeFile];
at the end of file written you should close the file.
You can also check the content written in file as NSString for debug point of view as mention above by #Glenn Smith:
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *outputFilePath = [documentsDirectory stringByAppendingPathComponent:#"file1.txt"];
NSError *error;
NSString *str = [NSString stringWithContentsOfFile:outputFilePath encoding:NSUTF8StringEncoding error:&error];
if (error != nil) {
NSLog(#"There was an error: %#", [error description]);
} else {
NSLog(#"Text file data: %#", str);
}