iOS SDK - MapKit MKAnnotationView 问题 - 位置和多个注释？

Question

快速进步，尝试学习进出 MapKit 和注释。

我取得了一些不错的进展，但是当我尝试添加位置服务时遇到了问题。

如果我返回 nil 到

     - (MKAnnotationView *)mapView:(MKMapView *)mapView 
                 viewForAnnotation:(id < MKAnnotation >)annotation

方法，我得到的结果非常接近我正在寻找的结果，我有我的注释图钉，我的用户位置以标准方式显示。

但如果我返回 myPins（所有参数设置如下），我会在 所有引脚 上得到正确的行为，但属性也是 为用户的位置设置（它是一个红色的大头针，每次视图移动或选择大头针时它都会落到位）。烦人。

如何将注释的属性与位置分开设置？有没有办法返回多个 MKAnnotationViews？我知道我缺少一些基本概念，但如果你能给我任何帮助，我将不胜感激。提前致谢。

这是我的主视图控制器，总共：

//
//  ViewController.m
//  mapFun
//


#import "ViewController.h"

@implementation ViewController
@synthesize segmentedControl;
@synthesize mapView,location, myLocations, myAnnotation, region;

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}

- (void)viewDidLoad
{
[super viewDidLoad];

self.mapView.delegate = self; 

//location manager stuff

CLLocationManager *locationManager = [[CLLocationManager alloc] init];
[locationManager setDelegate:self];
[locationManager setDistanceFilter:kCLDistanceFilterNone];
[locationManager setDesiredAccuracy:kCLLocationAccuracyBest];

if([CLLocationManager locationServicesEnabled])
{
[self.mapView setShowsUserLocation:YES];
[locationManager startUpdatingHeading]; 
}

[self loadUpLocations];

//set first zoom center and span, to zoom from to initial zoom

region.center=CLLocationCoordinate2DMake(
                                         33.75070416856952, 
                                         -84.37034368515015);
MKCoordinateSpan span;
span.latitudeDelta=.3;
span.longitudeDelta=.3;
region.span=span;

[mapView setRegion:region animated:YES];

}

- (void)viewDidUnload
{
[self setMapView:nil];
[self setSegmentedControl:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}

- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
}

- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];

//zoom to initial zoom
 [self setInitialZoom];
}

- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
}

- (void)viewDidDisappear:(BOOL)animated
{
[super viewDidDisappear:animated];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

//Load up a buncha locations

-(void)loadUpLocations{

myLocations =  [LoadObjectsFromFile loadFromFile:@"locations2" ofType:@"plist"];

//loop through and make annotations

for (NSString *loc in myLocations) {
    NSDictionary *value =[myLocations objectForKey:loc];

    //create instance of MapAnnotations
    CLLocationCoordinate2D temp = 
    CLLocationCoordinate2DMake(
                               [[value objectForKey:@"latitude"] doubleValue],
                               [[value objectForKey:@"longitude"] doubleValue]);

    myAnnotation = [[MapAnnotations alloc]initWithLocation:temp];
    myAnnotation.title = [value objectForKey:@"title"];
    myAnnotation.subtitle = [value objectForKey:@"subtitle"];
    myAnnotation.info =[value objectForKey:@"info"];

    [self.mapView addAnnotation:myAnnotation];

}
}

- (void)setInitialZoom{

// MKCoordinateRegion region;
region.center = CLLocationCoordinate2DMake(33.77, -84.37);

//set level of zoom
MKCoordinateSpan span;
span.latitudeDelta=.04;
span.longitudeDelta=.04;
region.span=span;
[mapView setRegion:region animated:YES];
}

// used when selecting annotations

- (void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)view{

MKPointAnnotation *selectedAnnotation = view.annotation;

NSLog(@"The annotation selected is %@.",selectedAnnotation.title);

//set level of zoom
CLLocationCoordinate2D newCenter = 
CLLocationCoordinate2DMake(
                           selectedAnnotation.coordinate.latitude,
                           selectedAnnotation.coordinate.longitude);
MKCoordinateSpan span;
span.latitudeDelta=.02;
span.longitudeDelta=.02;
MKCoordinateRegion zoomRegion = MKCoordinateRegionMake(newCenter, span);

[ self.mapView setRegion:zoomRegion animated:YES];

}

- (void)mapView:(MKMapView *)mapView didDeselectAnnotationView:(MKAnnotationView *)view
{
// [self zoomOutToInitial:nil];
}

- (IBAction)zoomOutToInitial:(id)sender {

[self.mapView setRegion:region animated:YES];
}

- (IBAction)segChanged:(id)sender {
if (self.segmentedControl.selectedSegmentIndex==0) {
    [self.mapView setMapType:MKMapTypeStandard];
}
if (self.segmentedControl.selectedSegmentIndex==1) {
    [self.mapView setMapType:MKMapTypeSatellite];
}
if (self.segmentedControl.selectedSegmentIndex==2) {
    [self.mapView setMapType:MKMapTypeHybrid];
}
}

// This gets called every time an annotation is in the map view

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id < MKAnnotation >)annotation
{
NSLog(@"Map view can see annotation %@.",annotation.title);
MKPinAnnotationView *myPins;
if (!myPins) {
    myPins= [[MKPinAnnotationView alloc]initWithAnnotation:self.myAnnotation 
                                  reuseIdentifier:@"myPins"];
}

myPins.animatesDrop = YES;
myPins.canShowCallout = YES;
myPins.rightCalloutAccessoryView = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];

return nil;
//return myPins;
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
[manager stopUpdatingHeading];
}
@end

---

回答我自己的问题。还是谢谢。

我终于在 Apple 的一个名为“Location Awareness Programming Guide”的有用文档中找到了答案。

这是更正 MKAnnotationView 方法：

// This gets called every time an annotation is in the map view

- (MKAnnotationView *)mapView:(MKMapView *)theView 
            viewForAnnotation:(id < MKAnnotation >)annotation
{
    NSLog(@"Map view can see annotation %@.",annotation.title);

   //if the annotation is a user location
    if ([annotation isKindOfClass:[MKUserLocation class]]) {
        return nil;
    }

//uses my custom class

if ([annotation isKindOfClass:[MapAnnotations class]]) {

    // try for reuse of pins

    MKPinAnnotationView *myPins = (MKPinAnnotationView *) 
              [theView dequeueReusableAnnotationViewWithIdentifier:@"myPins"];

    if (!myPins) {

            myPins= [[MKPinAnnotationView alloc]initWithAnnotation:annotation 
                                                   reuseIdentifier:@"myPins"];
            myPins.animatesDrop = YES;
            myPins.canShowCallout = YES;
            myPins.rightCalloutAccessoryView = 
            [UIButton buttonWithType:UIButtonTypeDetailDisclosure];

        }else
            myPins.annotation = annotation;
        return myPins;
    }
    return nil;
}

Answer 1

基本概念是当且仅当请求的视图实际上是用户位置视图时才返回。 您只需测试转发给您的 Annotation 是否属于 userlocation 类，如下所示：

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id < MKAnnotation >)annotation
{
  if ([annotation isKindOfClass:[MKUserLocation class]])
        return nil;
// do your usual stuff
}