Creating a Log File in an iOS app

Question

So in my app I have a bunch of data that I\'d like to write to a log file, and then display it within a UITextView when I click a button. I know how to toggle the

Answer 1

The basic idea is that you create the file, and append to it every time you log a new line. You can do it quite easily like this:

Writing to the file:

NSString *content = @"This is my log";

//Get the file path
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *fileName = [documentsDirectory stringByAppendingPathComponent:@"myFileName.txt"];

//create file if it doesn't exist
if(![[NSFileManager defaultManager] fileExistsAtPath:fileName])
    [[NSFileManager defaultManager] createFileAtPath:fileName contents:nil attributes:nil];

//append text to file (you'll probably want to add a newline every write)
NSFileHandle *file = [NSFileHandle fileHandleForUpdatingAtPath:fileName];
[file seekToEndOfFile];
[file writeData:[content dataUsingEncoding:NSUTF8StringEncoding]];
[file closeFile];

Reading:

//get file path
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *fileName = [documentsDirectory stringByAppendingPathComponent:@"myFileName.txt"];

//read the whole file as a single string
NSString *content = [NSString stringWithContentsOfFile:fileName encoding:NSUTF8StringEncoding error:nil];