Reading float from a custom file - objective-c

Question

I want to read some float value one by one from a custom file I defined "player.geo".
player.geo is a file I created using Xcode 4 ("Empty File" from the File > New menu)
I'm currently trying to do it like this:
- (id) initWithGeometryFile:(NSString *) nameOfFile
{
NSFileHandle *geoFile = NULL;
NSString *geoFilePath = [[NSBundle mainBundle] pathForResource:#"player" ofType:#"geo"];
geoFile = [NSFileHandle fileHandleForReadingAtPath:geoFilePath];
if(geoFile == NULL)
{
NSLog(#"Failed to open file.");
}
else
{
NSLog(#"Opening %# successful", nameOfFile);
NSMutableData *fileData = [[NSMutableData alloc] initWithData:[geoFile readDataOfLength:4]];
float firstValue;
[fileData getBytes:&firstValue length:sizeof(float)];
NSLog(#"First value in file %# is %f", nameOfFile, firstValue);
}
return self;
}
I'm not getting the expected value of -64.0, rather I'm getting 0.0.
Is this the right way to go about it?
Do I really have to read the file as a string and then parse float the string contents to get the float value?

Answer 1

NSData objects deal with raw bytes, not strings. If you are typing in a string into a txt file, this will not work. If you are using NSData objects, then you will need to first write the data using the data object methods such as writeToFile:atomically:.
Alternately, you can use the NSString functions stringWithContentsOfFile and componentsSeperatedByString to generate an NSArray containing each string on it's own line, like so:
NSString *tmp;
NSArray *lines;
lines = [[NSString stringWithContentsOfFile:#"testFileReadLines.txt"]
componentsSeparatedByString:#"\n"];
NSEnumerator *nse = [lines objectEnumerator];
while(tmp = [nse nextObject]) {
NSLog(#"%#", tmp);
}