代表没有回应

Question

我试图在两个Viewcontrollers之间使用委托,但不幸的是我的代表没有被解雇.我希望有人可以帮我解决问题.我有一个名为MapBackgroundViewController的ViewContoller和一个名为MapsViewController的ViewContoller.如果MapsBackgroundViewController的SegmentedControl发生更改,则应通知MapsViewController.(我实际上尝试在iPhone上使用地面卷曲实现类似地图应用程序的东西)

这是我的代码的一部分:

MapBackgroundViewController.h

@protocol ChangeMapTyp <NSObject>
@required
- (void)segmentedControllChangedMapType:(MKMapType) type ;
@end


@interface MapBackgroundViewController : UIViewController{
IBOutlet UISegmentedControl *segmentedControl;
MKMapType mapType;
id < ChangeMapTyp> delegate;

}


@property IBOutlet UISegmentedControl *segmentedControl;

@property MKMapType mapType;

@property(strong)id delegate;

- (IBAction)segmentedControllChanged:(id)sender;

MapBackgroundViewController.m

@interface MapBackgroundViewController ()

@end

@implementation MapBackgroundViewController
@synthesize segmentedControl, mapType, delegate;


- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.

[self setDelegate:self];

NSLog(@"%@",self.delegate);

}


- (IBAction)segmentedControllChanged:(id)sender {

if (segmentedControl.selectedSegmentIndex == 0) {
    mapType = MKMapTypeStandard;
}else if (segmentedControl.selectedSegmentIndex == 1) {
    mapType = MKMapTypeSatellite;
} else if (segmentedControl.selectedSegmentIndex == 2) {
 //   [self.delegate setMapType:MKMapTypeHybrid];
    mapType = MKMapTypeHybrid;
}


//Is anyone listening

NSLog(@"%@",self.delegate);

if([self.delegate respondsToSelector:@selector(segmentedControllChangedMapType:)])
{
    //send the delegate function with the amount entered by the user
    [self.delegate segmentedControllChangedMapType:mapType];
}

[self dismissModalViewControllerAnimated:YES];

}

MapsViewController.h

#import "MapBackgroundViewController.h"

@class MapBackgroundViewController;

@interface MapsViewController : UIViewController<MKMapViewDelegate,
UISearchBarDelegate,  ChangeMapTyp >{
 IBOutlet MKMapView *map;
}


@property (nonatomic, retain) IBOutlet MKMapView *map;


@end

MapsViewController.m(以下方法由于某种原因从未调用过)

 - (void)segmentedControllChangedMapType: (MKMapType) type{
    map.mapType = type;
 }

Answer 1

在MapBackgroundViewController您已设置的delegate属性self,所以委托是self- ( MapBackgroundViewController),所以当您执行检查if([self.delegate respondsToSelector:@selector(segmentedControllChangedMapType:)])它返回NO,因为self.delegate(这是self,这是MapBackgroundViewController),未实现此方法.如果您希望自己MapsViewController成为委托人,MapBackgroundViewController那么您必须拥有MapsViewController(例如,调用myMapsViewController)实例,然后设置self.delegate = myMapsViewController.