玩转Map Kit (part3)

原文地址：http://blog.objectgraph.com/index.php/2009/04/08/iphone-sdk-30-playing-with-map-kit-part-3/

说明：本人Ｅ文水平有限，如有不足之处还请指正

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有许多人问我如何在地图组件上绘制拆线。从我看到文档中，没有一个提供这样的课程。

你可以使用Quartz在视图上进行绘制。但我觉得直接在地图组件上绘制是没有用的。

如果你已经理解了我先前提交的文章，现在你可以很容易的做到如下：

－显示地图组件的不同风格

－显示当前位置

－获取当前的位置

－创建一个标注

－反转Geocode 的经纬度以获得更多的位置信息

所以，只需要使用这些有限的API,您就可以创建出不同类型的应用程序

– Friend Track Apps (Like Loopt)
– Car Park Finder (Just add an annotation where you left the car)

 

我发现了获取用户位置的最好的方法，就是使用Core Location.因为它提供了一个很好的委托，可以让我们知道什么时候从GPS异步获得坐标。

因此我可以结合MapKit和core Location API 去放大你当前的位置及放置标注(Annotation)

这里有一些代码：

头文件

#import "FlipsideViewController.h"#import "ParkPlaceMark.h"#import <MapKit/MapKit.h>#import <MapKit/MKReverseGeocoder.h>#import <CoreLocation/CoreLocation.h> @interface MainViewController : UIViewController <FlipsideViewControllerDelegate, MKMapViewDelegate, MKReverseGeocoderDelegate, CLLocationManagerDelegate> {MKMapView *mapView;MKPlacemark *mPlacemark;CLLocationCoordinate2D location;IBOutlet UIButton *mStoreLocationButton; } - (IBAction)showInfo;- (IBAction)storeLocationInfo:(id) sender; @end

代码文件

#import "MainViewController.h"#import "MainView.h" @implementation MainViewController - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) { // Custom initialization } return self;} // Implement viewDidLoad to do additional setup after loading the view, typically from a nib. - (void)viewDidLoad { [super viewDidLoad]; mapView=[[MKMapView alloc] initWithFrame:self.view.frame]; //mapView.showsUserLocation=TRUE; mapView.delegate=self; [self.view insertSubview:mapView atIndex:0]; CLLocationManager *locationManager=[[CLLocationManager alloc] init]; locationManager.delegate=self; locationManager.desiredAccuracy=kCLLocationAccuracyNearestTenMeters; [locationManager startUpdatingLocation]; } - (void)flipsideViewControllerDidFinish:(FlipsideViewController *)controller { [self dismissModalViewControllerAnimated:YES];} - (IBAction)showInfo { FlipsideViewController *controller = [[FlipsideViewController alloc] initWithNibName:@"FlipsideView" bundle:nil];controller.delegate = self; controller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;[self presentModalViewController:controller animated:YES]; [controller release];} - (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.// e.g. self.myOutlet = nil;} - (void)dealloc { [super dealloc];} - (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailWithError:(NSError *)error{} - (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFindPlacemark:(MKPlacemark *)placemark{NSLog(@"Geocoder completed");mPlacemark=placemark;[mapView addAnnotation:placemark];} - (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation{NSLog(@"This is called");MKPinAnnotationView *test=[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"parkingloc"];if([annotation title]==@"Parked Location"){[test setPinColor:MKPinAnnotationColorPurple];}else{[test setPinColor:MKPinAnnotationColorGreen];}return test;} - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation{mStoreLocationButton.hidden=FALSE;location=newLocation.coordinate;//One location is obtained.. just zoom to that location MKCoordinateRegion region;region.center=location;//Set Zoom level using SpanMKCoordinateSpan span;span.latitudeDelta=.005;span.longitudeDelta=.005;region.span=span; [mapView setRegion:region animated:TRUE]; } - (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error{} - (IBAction)storeLocationInfo:(id) sender{//Either we can use geocoder to get a placemark or just create our own./*MKReverseGeocoder *geocoder=[[MKReverseGeocoder alloc] initWithCoordinate:location];geocoder.delegate=self;[geocoder start];*///Our own ParkPlaceMark *placemark=[[ParkPlaceMark alloc] initWithCoordinate:location];[mapView addAnnotation:placemark];} @end

您也可以使用反向地理编码器（reverse Geocoder ）获得地标(PlaceMark)或创建自己的标注(Annotation).下面是一些关于如何通过实现MKAnnotation 协议(protocal)快速创建自己的标注（Annotation）

头文件

#import <Foundation/Foundation.h>#import <MapKit/MapKit.h> @interface ParkPlaceMark : NSObject<MKAnnotation> {CLLocationCoordinate2D coordinate;}@property (nonatomic, readonly) CLLocationCoordinate2D coordinate;-(id)initWithCoordinate:(CLLocationCoordinate2D) coordinate;- (NSString *)subtitle;- (NSString *)title; @end @end

源文件

#import "ParkPlaceMark.h" @implementation ParkPlaceMark@synthesize coordinate; - (NSString *)subtitle{return @"Put some text here";}- (NSString *)title{return @"Parked Location";} -(id)initWithCoordinate:(CLLocationCoordinate2D) c{coordinate=c;NSLog(@"%f,%f",c.latitude,c.longitude);return self;}@end

 

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