iphone开发/ios开发编程罗盘/指南针开发

#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>

@interface CompasViewController : UIViewController<CLLocationManagerDelegate> {
    IBOutlet UIImageView *arrow;
    IBOutlet UILabel *angel;
    CLLocationManager *locManager;
}
@property (retain) CLLocationManager *locManager;
@property (retain,nonatomic)IBOutlet UILabel *angel;

@end

#import "CompasViewController.h"

@implementation CompasViewController
@synthesize locManager,angel;

- (void)dealloc
{
    [super dealloc];
}
#pragma mark - View lifecycle
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    NSLog(@"Location manager error: %@", [error description]);
}

- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading
{
    CGFloat heading = -1.0f * M_PI * newHeading.magneticHeading / 180.0f;
    angel.text=[[NSString alloc]initWithFormat:@"angle:%f",newHeading.magneticHeading];
    arrow.transform = CGAffineTransformMakeRotation(heading);
}

- (BOOL)locationManagerShouldDisplayHeadingCalibration:(CLLocationManager *)manager
{
    return YES;
}


- (void)viewDidLoad
{
    [super viewDidLoad];
    self.navigationController.navigationBar.tintColor = COOKBOOK_PURPLE_COLOR;
   
    self.locManager = [[[CLLocationManager alloc] init] autorelease];
    self.locManager.delegate = self;
    if ([CLLocationManager headingAvailable])
        [self.locManager startUpdatingHeading];
    else
    {
        UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"atention" message:@"compass not Available" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];
        [alert show];
        arrow.alpha = 0.0f;
    }
}

@end