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espinallab on 02/08/10

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Distance Travel

/ Published in: Objective C

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//
// DistanceViewController.h
// Distance
//
// Created by Steve Baker on 1/30/10.
// Copyright Beepscore LLC 2010. All rights reserved.
//
 
#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>
 
// Note we only write to the textFields, not edit, respond to keyboard input or read from them.
// So we don't need to conform to or implememnt <UITextFieldDelegate> protocol
// Ref Dudney sec 4.6 pg 65-66
@interface DistanceViewController : UIViewController <CLLocationManagerDelegate> {
    
    CLLocationManager *locationManager;
    NSMutableArray *locations;
    UILabel *lastUpdate;
    UILabel *totalDistance;
    UILabel *averageSpeed;
    
}
#pragma mark -
#pragma mark properties
 
@property(nonatomic,retain)CLLocationManager *locationManager;
@property(nonatomic,retain)NSMutableArray *locations;
@property(nonatomic,retain)IBOutlet UILabel *lastUpdate;
@property(nonatomic,retain)IBOutlet UILabel *totalDistance;
@property(nonatomic,retain)IBOutlet UILabel *averageSpeed;
 
- (void)updateDisplay;
 
@end

//
// DistanceViewController.m
// Distance
//
// Created by Steve Baker on 1/30/10.
// Copyright Beepscore LLC 2010. All rights reserved.
//
 
#import "DistanceViewController.h"
 
@implementation DistanceViewController
 
 
#pragma mark -
#pragma mark properties
 
@synthesize locationManager;
@synthesize locations;
@synthesize lastUpdate;
@synthesize totalDistance;
@synthesize averageSpeed;
 
#pragma mark -
#pragma mark initializers
/*
// The designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
// Custom initialization
}
return self;
}
*/
 
/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/
 
 
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
    self.locationManager = [[[CLLocationManager alloc] init] autorelease];
    self.locationManager.delegate = self;
    // notify us only if distance changes by 10 meters or more
    self.locationManager.distanceFilter = 10.0f;
    self.locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters;
    [self.locationManager startUpdatingLocation];
    // 32 is a guess of a 'good' number
    self.locations = [NSMutableArray arrayWithCapacity:32];
}
 
 
/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/
 
 
#pragma mark destructors and memory cleanUp
// use cleanUp method to avoid repeating code in setView, viewDidUnload, and dealloc
- (void)cleanUp {
    [locationManager release], locationManager = nil;
    [locations release], locations = nil;
    [lastUpdate release], lastUpdate = nil;
    [totalDistance release], totalDistance = nil;
    [averageSpeed release], averageSpeed = nil;
}
 
 
// Release IBOutlets in setView.
// Ref http://developer.apple.com/iPhone/library/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmNibObjects.html
//
// http://moodle.extn.washington.edu/mod/forum/discuss.php?d=3162
- (void)setView:(UIView *)aView {
    
    if (!aView) { // view is being set to nil
        // set outlets to nil, e.g.
        // self.anOutlet = nil;
        [self cleanUp];
    }
    // Invoke super's implementation last
    [super setView:aView];
}
 
 
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
 
// Release any cached data, images, etc that aren't in use.
}
 
 
- (void)viewDidUnload {
// Release any retained subviews of the main view.
[self cleanUp];
}
 
 
 
- (void)dealloc {
    [self cleanUp];
    [super dealloc];
}
 
#pragma mark Location methods
- (void)locationManager:(CLLocationManager *)manager
    didUpdateToLocation:(CLLocation *)newLocation
           fromLocation:(CLLocation *)oldLocation {
    // if we have a valid location, and it's within 20 meters then stop
    // updating location, but turn it back on in 60 seconds.
    if (newLocation.horizontalAccuracy > 0.0f
        && newLocation.horizontalAccuracy < 20.0f) {
        if (self.locations.count > 3) {
            [self.locationManager stopUpdatingLocation];
            [self.locationManager performSelector:@selector(startUpdatingLocation)
                                       withObject:nil
                                       afterDelay:60.0f];
        }
        [self.locations addObject:newLocation];
        [self updateDisplay];
    }
}
 
- (CLLocationDistance)totalDistanceTraveled {
    CGFloat totalDistanceTraveled = 0.0f;
    CLLocation *oldLocation = nil;
    for (CLLocation *location in self.locations) {
        if (nil == oldLocation) {
            oldLocation = location;
            // continue skips the rest of the for loop
            continue;
        }
        totalDistanceTraveled += fabs([location getDistanceFrom:oldLocation]);
        oldLocation = location;
    }
    return totalDistanceTraveled;
}
 
- (NSTimeInterval)timeDelta {
    NSDate *first = [(CLLocation *)[self.locations objectAtIndex:0] timestamp];
    NSDate *last = [(CLLocation *)[self.locations lastObject] timestamp];
    return [last timeIntervalSince1970] - [first timeIntervalSince1970];
}
 
 
#pragma mark -
- (void)updateDisplay {
    CLLocationDistance distance = [self totalDistanceTraveled];
    totalDistance.text = [NSString stringWithFormat:@"%5.3f", distance];
    
    NSTimeInterval time = [self timeDelta];
    // don't want to divide by zero
    if (0.0f == time) {
        averageSpeed.text = @"0.000";
    } else {
        averageSpeed.text = [NSString stringWithFormat:@"%5.3f", distance/time];
    }
    NSDateFormatter *inputFormatter = [[[NSDateFormatter alloc] init] autorelease];
    [inputFormatter setDateFormat:@"HH:mm:ss.SSSS"];
    NSDate *date = [(CLLocation *)[self.locations lastObject] timestamp];
    lastUpdate.text = [inputFormatter stringFromDate:date];
}
 
@end

URL: http://github.com/beepscore/Distance/tree/master/Classes/

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