flipsideviewcontroller.m

This is an example application that shows how to use the Location services on the iPhone.

/*

File: FlipsideViewController.m
Abstract: Controller class for the "flipside" view, which contains all the
controls for settings.

Version: 1.1

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*/

#import "FlipsideViewController.h"
#import "AccuracyPickerItem.h"

@implementation FlipsideViewController

@synthesize flipDelegate, filterControls;
@synthesize accuracyPicker, distanceFilterSwitch, distanceFilterSlider, distanceFilterValueLabel;
@synthesize distanceFilterSliderLabel1, distanceFilterSliderLabel2, distanceFilterSliderLabel3, distanceFilterSliderLabel4;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
	if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
		// This array is used to keep the values and associated strings for our picker view
		// The AccuracyPickerItem class is a helper class defined in its own source file
		pickerItems = [[NSArray alloc] initWithObjects:[[[AccuracyPickerItem alloc] initWithName:NSLocalizedString(@"AccuracyBest", @"Best") value:kCLLocationAccuracyBest] autorelease],
					   [[[AccuracyPickerItem alloc] initWithName:NSLocalizedString(@"Accuracy10", @"10 meters") value:kCLLocationAccuracyNearestTenMeters] autorelease],
					   [[[AccuracyPickerItem alloc] initWithName:NSLocalizedString(@"Accuracy100", @"100 meters") value:kCLLocationAccuracyHundredMeters] autorelease],
					   [[[AccuracyPickerItem alloc] initWithName:NSLocalizedString(@"Acurracy1000", @"1 kilometer") value:kCLLocationAccuracyKilometer] autorelease],
					   [[[AccuracyPickerItem alloc] initWithName:NSLocalizedString(@"Accuracy3000", @"3 kilometers") value:kCLLocationAccuracyThreeKilometers] autorelease], nil];
	}
	return self;
}

- (void)viewDidLoad {
	// Special color for "reverse" views
	self.view.backgroundColor = [UIColor viewFlipsideBackgroundColor];		
	
	// This array contains all the controls toggled by the "Distance Filter" switch
	// This allows us to easily enable / disable the controls when the state of the switch changes
	// We do this here instead of in the init because the objects are nil while in the init method
	self.filterControls = [NSArray arrayWithObjects:distanceFilterSlider, distanceFilterValueLabel, distanceFilterSliderLabel1, distanceFilterSliderLabel2, distanceFilterSliderLabel3, distanceFilterSliderLabel4, nil];
}

- (void)viewWillAppear:(BOOL)animated {
	// Set up the controls to the right initial values, based on the current state of the CoreLocation object
	[self setControlStatesFromSource:[MyCLController sharedInstance]];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
	return (interfaceOrientation == UIInterfaceOrientationPortrait); // Portrait mode only
}


- (void)didReceiveMemoryWarning {
	[super didReceiveMemoryWarning]; // Releases the view if it doesn't have a superview
	// Release anything that's not essential, such as cached data
}

- (void)dealloc {
	[accuracyPicker release];
	[distanceFilterSwitch release];
	[distanceFilterSlider release];
	[distanceFilterValueLabel release];
	[distanceFilterSliderLabel1 release];
	[distanceFilterSliderLabel2 release];
	[distanceFilterSliderLabel3 release];
	[distanceFilterSliderLabel4 release];
    
	[filterControls release];
	[pickerItems release];
	[super dealloc];
}

#pragma mark ---- UIPickerViewDataSource delegate methods ----

// returns the number of columns to display.
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
	return 1;
}

// returns the number of rows
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
	return [pickerItems count];
}

#pragma mark ---- UIPickerViewDelegate delegate methods ----

// returns the title of each row
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
	AccuracyPickerItem *currentItem = [pickerItems objectAtIndex:row];
	return currentItem.displayName;
}

// gets called when the user settles on a row
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
	AccuracyPickerItem *currentItem = [pickerItems objectAtIndex:row];
	accuracyToSet = currentItem.accuracyValue;
}

#pragma mark ---- Other control callbacks ----

// Causes the new settings to take effect
// Tells the root view via a delegate to flip back over to the main view
- (IBAction)doneButtonPressed:(id)sender {
	// This is where we actually set the values that the user has chosen. Some apps
	// set the value immediately whenever the user "settles" on a value in a control
	// (such as didSelectRow). We choose to only actually commit the values once the
	// "Done" button has been tapped, and only if they differ from the previous state.
	if (accuracyToSet != previousAccuracy) {
		[MyCLController sharedInstance].locationManager.desiredAccuracy = accuracyToSet;
	}
	if (filterToSet != previousFilter) {
		[MyCLController sharedInstance].locationManager.distanceFilter = filterToSet;
	}

	// Tell the root view to flip back over to the main view
	[self.flipDelegate toggleView:self];
}

// Toggles the "enabled" state all of the controls associated with the filter value
- (void) setFilterControlsEnabled:(BOOL)state {
	for (UIControl *control in filterControls) {
		control.enabled = state;
	}
}

// Called when the switch is flipped
- (IBAction)switchAction:(id)sender {
	BOOL newState = [sender isOn];
	
	// Controls are disabled if switch is off
	[self setFilterControlsEnabled:newState];
	
	// If the switch is on, distance filter is current slider value, otherwise set it to "none"
	if ( newState ) {
		[self sliderValueChanged:self];
	} else {
		filterToSet = kCLDistanceFilterNone;
	}
}

// Takes the value of the slider and puts it in a label underneath it
- (void) updateSliderLabel {
	double value = pow(10, [distanceFilterSlider value]);
	distanceFilterValueLabel.text = [NSString stringWithFormat:@"%.0f %@", value, (value < 1.5) ? NSLocalizedString(@"MeterSingular", @"meter") : NSLocalizedString(@"MeterPlural", @"meters")];
}

// Called when the slider is moved, with live updating
- (IBAction)sliderValueChanged:(id)sender {
	// The distance filter slider is an exponential scale, base 10.
	// Slider returns a value in the range 0.0 to 3.0 (set in Interface Builder).
	// Corresponds to a range of 1 to 1000, exponentially.
	filterToSet = pow(10, distanceFilterSlider.value);
	[self updateSliderLabel];
}

// Sets the state of the controls based on the state of the location manager
- (void) setControlStatesFromSource:(MyCLController *) clDelegate {
	// Current values from the source object
	previousAccuracy = accuracyToSet = clDelegate.locationManager.desiredAccuracy;
	previousFilter = filterToSet = clDelegate.locationManager.distanceFilter;
	
	// Set up accuracy controls
	for (AccuracyPickerItem *currentItem in pickerItems) {
		if (currentItem.accuracyValue == previousAccuracy) {
			[accuracyPicker selectRow:[pickerItems indexOfObject:currentItem] inComponent:0 animated:NO];
		}
	}
	
	// Set up filter controls
	// Since the slider is exponential (base 10), converting the other way is done with a base 10 logarithm.
	// If the filter is set to "none", we choose a default value of 10 (log10 of which is 1, hard coded below).
	[distanceFilterSwitch setOn:(previousFilter != kCLDistanceFilterNone) animated:NO];
	[distanceFilterSlider setValue:((previousFilter == kCLDistanceFilterNone) ? 1 : log10(fabs(previousFilter))) animated:NO];
	[self updateSliderLabel];
	[self setFilterControlsEnabled:[distanceFilterSwitch isOn]];
}	

@end