UISlider core data programing - cocoa-touch

Question

Im working on a simple "point based" app.
under settings the user set´s the number of points needed to get a "goodie" using a slider.
-(IBAction) sliderChanged: (id)sender {
UISlider *slider = (UISlider *) sender;
int progressAsInt =(int)(slider.value +0.5);
NSString *newText = [[NSString alloc] initWithFormat:#"%d",progressAsInt];
sliderLabel.text = newText;
[newText release];
this works fine, but how so i store the slider value in my core data model, and how do make my slider show the stored value when view loads.
hope u can help me out :-D
Hey gerry3 i found my error. i never set my toD-object in my settingsViewController, with:
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:[NSEntityDescription
entityForName:#"ToDo" inManagedObjectContext:_context]];
NSError *error = nil;
NSArray *array = [_context executeFetchRequest:request error:&error];
if (array == nil)
{
// Deal with error...
}
if(array.count > 0){
toDo = [array objectAtIndex:0];
} else { // no one to fetch - generate one
toDo = [NSEntityDescription
insertNewObjectForEntityForName:#"ToDo"
inManagedObjectContext:_context];
[toDo retain];
your code works like a charm .....
Thanks
Skov

Answer 1

The key here is that Core Data stores numeric attributes (e.g. integers, floats, etc) as NSNumber objects.
Say that your entity is called Record and it has a integer attribute called 'progress'.
If you create a managed object instance of Record named 'record', then you can set its progress like this:
[record setValue:[NSNumber numberWithInteger:progressAsInt] forKey:#"progress"];
When you want to update your view with the value from your model (usually in viewWillAppear:), you can get its progress like this:
NSNumber *progressNumber = [record valueForKey:#"progress"];
slider.value = [progressNumber floatValue];
Alternatively, if you generate the class files for the Record entity, you can just do:
record.progress = [NSNumber numberWithInteger:progressAsInt];
and:
slider.value = [record.progress floatValue];