使用多个引脚计算路由

Question

在我的应用程序中，我有一个带有几个自定义引脚的mapView。

我正在尝试这样做:在showCallout上出现一个AlertView，告诉您是否要计算路由。这是有效的，但只适用于一个位置。或者更好的是，只调用一个方法，所以我只有一个目的地。

以下是我的代码(我有9个目的地，但为了使代码更简短，我只发布了2个)：

- (void)viewDidLoad
{
[super viewDidLoad];

[mapView setMapType:MKMapTypeStandard];
[mapView setZoomEnabled:YES];
[mapView setScrollEnabled:YES];
[mapView setDelegate:(id)self];

MKCoordinateRegion TavernaCongiura = { {0.0, 0.0} , {0.0, 0.0} };
TavernaCongiura.center.latitude = 40.380784;
TavernaCongiura.center.longitude = 15.541373;
TavernaCongiura.span.longitudeDelta = 0.004f;
TavernaCongiura.span.latitudeDelta = 0.004f;
[mapView setRegion:TavernaCongiura animated:YES];
mapView.showsUserLocation = YES;

TeggianoAnnotation *ann0 = [[TeggianoAnnotation alloc] init];
ann0.title = @"Taverna de la Congiura";
ann0.subtitle = @"Antipasto";
ann0.coordinate = TavernaCongiura.center;
[mapView addAnnotation: ann0];

MKCoordinateRegion TavernaDeiMori = { {0.0, 0.0} , {0.0, 0.0} };
TavernaDeiMori.center.latitude = 40.380535;
TavernaDeiMori.center.longitude = 15.542028;
TavernaDeiMori.span.longitudeDelta = 0.004f;
TavernaDeiMori.span.latitudeDelta = 0.004f;
[mapView setRegion:TavernaDeiMori animated:YES];

TeggianoAnnotation *ann1 = [[TeggianoAnnotation alloc] init];
ann1.title = @"Taverna dei Mori";
ann1.subtitle = @"Parmatieddi";
ann1.coordinate = TavernaDeiMori.center;
[mapView addAnnotation: ann1];

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation    
*)newLocation fromLocation:(CLLocation *)oldLocation {
if (newLocation.horizontalAccuracy == oldLocation.horizontalAccuracy) {
    [self->locationManager stopUpdatingLocation];
    CLLocationCoordinate2D coords = newLocation.coordinate;
    NSString *stringURL = [NSString stringWithFormat:@"http://maps.google.com 
/maps?saddr=%g,%g&daddr=40.380784,15.541373", coords.latitude, coords.longitude];
    NSURL *url = [NSURL URLWithString:stringURL];
    [[UIApplication sharedApplication] openURL:url];
}
}

- (void)locationManagerMori:(CLLocationManager *)manager didUpdateToLocation: 
(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
if (newLocation.horizontalAccuracy == oldLocation.horizontalAccuracy) {
    [self->locationManager stopUpdatingLocation];
    CLLocationCoordinate2D coords = newLocation.coordinate;
    NSString *stringURL = [NSString stringWithFormat:@"http://maps.google.com
/maps?saddr=%g,%g&daddr=40.380535,15.542028", coords.latitude, coords.longitude];
    NSURL *url = [NSURL URLWithString:stringURL];
    [[UIApplication sharedApplication] openURL:url];
}
}

-(MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:    
(id<MKAnnotation>)annotation {
MKAnnotationView *MyPin=[[MKAnnotationView alloc] initWithAnnotation:annotation   
reuseIdentifier:@"current"];

UIButton *advertButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
if ([[annotation title] isEqualToString:@"Taverna de la Congiura"]) {
    [advertButton addTarget:self action:@selector(buttonCongiura:) 
forControlEvents:UIControlEventTouchUpInside];
    MyPin.image = [UIImage imageNamed:@"CongiuraMappa.png"];    
}
if ([[annotation title] isEqualToString:@"Taverna dei Mori"]) {
    [advertButton addTarget:self action:@selector(buttonMori:) 
forControlEvents:UIControlEventTouchUpInside];
    MyPin.image = [UIImage imageNamed:@"MoriMappa.png"];    
}
MyPin.rightCalloutAccessoryView = advertButton;
MyPin.draggable = NO;
MyPin.highlighted = YES;
MyPin.canShowCallout = YES;
return MyPin;
}

-(void)buttonCongiura:(id)sender {
UIAlertView *alertViewCongiura;
alertViewCongiura = [[UIAlertView alloc] initWithTitle:@"Taverna de la Congiura" 
message:@"Calcola Percorso" delegate:self cancelButtonTitle:@"Annulla"   
otherButtonTitles:@"Calcola", nil];
[alertViewCongiura show];
}

-(void)buttonMori:(id)sender {
UIAlertView *alertViewMori;
alertViewMori = [[UIAlertView alloc] initWithTitle:@"Taverna dei Mori" 
message:@"Calcola Percorso" delegate:self cancelButtonTitle:@"Annulla" 
otherButtonTitles:@"Calcola", nil];
[alertViewMori show];
}

-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex 
{   
if (buttonIndex == 1) {
  self->locationManager = [[CLLocationManager alloc] init];
  self->locationManager.delegate = (id)self;
  [self->locationManager startUpdatingLocation];
}

if (buttonIndex == 2) {
    self->locationManagerMori = [[CLLocationManager alloc] init];
    self->locationManagerMori.delegate = (id)self;
    [self->locationManagerMori startUpdatingLocation];
}
}

问题是，只有第一个

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation    
*)newLocation fromLocation:(CLLocation *)oldLocation

是调用的。

Answer 1

对于正在使用的每个位置管理器实例，不能对委托方法使用不同的名称。每个位置管理器仍将调用CLLocationManagerDelegate协议定义的方法。

您可以通过检查manager参数是否等于您正在创建的实例之一来检查哪个管理器正在调用(例如，if (manager == locationManagerMori))。

但是您不需要从一开始就为每个注释创建单独的位置管理器实例。

相反，只保留一个位置管理器实例，在委托方法中，您可以找出当前选择的注释是什么，并在url字符串中使用它的坐标。例如：

- (void)locationManager:(CLLocationManager *)manager 
    didUpdateToLocation:(CLLocation *)newLocation 
    fromLocation:(CLLocation *)oldLocation 
{
    if (newLocation.horizontalAccuracy == oldLocation.horizontalAccuracy) 
      //the above if-condition looks a little suspicious by the way
    {
        if (mapView.selectedAnnotations.count == 0)
        {
            //no annotation selected, do nothing
            return;
        }

        //there can only be one selected annotation so get the one at index 0
        id<MKAnnotation> selectedAnnotation = 
            [mapView.selectedAnnotations objectAtIndex:0];


        [self->locationManager stopUpdatingLocation];
        CLLocationCoordinate2D coords = newLocation.coordinate;

        NSString *stringURL = [NSString stringWithFormat:
            @"http://maps.google.com/maps?saddr=%g,%g&daddr=%g,%g", 
            coords.latitude, coords.longitude, 
            selectedAnnotation.coordinate.latitude, 
            selectedAnnotation.coordinate.longitude];

        NSURL *url = [NSURL URLWithString:stringURL];

        //stop updating location to avoid possible endless loop
        //when user comes back to this app...
        [manager stopUpdatingLocation];

        [[UIApplication sharedApplication] openURL:url];
    }
}

您也不需要为每个注释使用单独的按钮操作方法。您可以只创建一个按钮操作方法，并使用相同的技术来获得所选的注释。

另一个问题存在于警报视图的clickedButtonAtIndex方法中。您似乎是通过查看警报视图的按钮索引来检查它是哪个注释。该索引将是Annulla或Calcola按钮(而不是哪个注释)。

因为您不需要为每个注释创建单独的位置管理器，所以您不需要知道警报视图用于哪个注释。您只需检查用户是否点击了Annulla或Calcola：

if (buttonIndex == alertView.firstOtherButtonIndex)
{
    self->locationManager = [[CLLocationManager alloc] init];
    self->locationManager.delegate = (id)self;
    self->locationManager startUpdatingLocation];
}