How Can i get data from the file in the documents folder

Question

i am new to xcode and objective c.

firstly i have created a file in documents directory and it is created and now what i need is how can i read the data from that file like whether the file is containing a particular string or not

How can i get that

Answer 1

You can follow my answer here, saving and retrieving plist files

Array from File in XCode

Answer 2

Following method will get the contents of the file to a string.

+ (id)stringWithContentsOfFile:(NSString *)path
              usedEncoding:(NSStringEncoding *)enc
                     error:(NSError **)error

You can then find out if the returned string contains specified substring by:

NSRange textRange;
textRange =[string rangeOfString:@"ohai"];

if(textRange.location != NSNotFound) {

    //String contains substring "ohai"
}

Hope this helps.

Answer 3

the same way as you write you can retrieve the data , lets assume you want to get an image from your documents folder then see this code -

NSString *stringPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,  NSUserDomainMask, YES)objectAtIndex:0]];
NSString *fileName = [stringPath stringByAppendingFormat:@"/image.jpg"];

//fileName is your image path and image.jpg is your image name which is saved in documents folder...
NSData *retrieveData = [NSData dataWithContentsOfFile:fileName];
UIImage *newImage = [UIImage imageWithData: retrieveData];

in this case instead of

[data writeToFile:fileName atomically:YES]; 

you have to write

NSData *retrieveData = [NSData dataWithContentsOfFile:fileName];

line. And you can get all kind of data.

Thank You!!

Answer 4

You can read data from file in documents folder in following way:

 NSString *filePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/<pathofFile>"];
 NSString *fileContent = [[NSString alloc] initWithContentOfFile:filePath encoding:NSUTF8StringEncoding error:nil];

Now, you can use NSString methods for searching substring in the fileContent.