在地图视图上拖动注释引脚 [英] Drag an annotation pin on a mapview
问题描述
注释引脚是可拖动的,但我无法将其放到目标位置。问题是如何获取目标位置的坐标,我放下注释引脚?是否存在任何方法?
The annotation pin is draggable but I couldn't drop it to the destination location. The problem is how could I get the destination location's coordinate where i drop the annotation pin? Any method exist?
编辑1:
注释引脚的中心似乎永远不会改变我丢弃引脚的地方。
The center of the annotation pin seems never changed where ever I drop the pin.
- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)annotationView didChangeDragState:(MKAnnotationViewDragState)newState
fromOldState:(MKAnnotationViewDragState)oldState
{
if (newState == MKAnnotationViewDragStateEnding)
{
NSLog(@"x is %f", annotationView.center.x);
NSLog(@"y is %f", annotationView.center.y);
CGPoint dropPoint = CGPointMake(annotationView.center.x, annotationView.center.y);
CLLocationCoordinate2D newCoordinate = [self.mapView convertPoint:dropPoint toCoordinateFromView:annotationView.superview];
[annotationView.annotation setCoordinate:newCoordinate];
}
}
编辑2:
Annotation.h
Annotation.h
@property (nonatomic,readwrite,assign) CLLocationCoordinate2D coordinate;
Annotation.m
Annotation.m
- (void)setCoordinate:(CLLocationCoordinate2D)newCoordinate {
coordinate = newCoordinate;
}
编辑3:
我拖动引脚,掉落的NSLog输出始终是相同的。
Edit 3: where ever I drag the pin, the NSLog out put of the droppedAt is always the same.
- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)annotationView didChangeDragState:(MKAnnotationViewDragState)newState
fromOldState:(MKAnnotationViewDragState)oldState
{
if (newState == MKAnnotationViewDragStateEnding)
{
CLLocationCoordinate2D droppedAt = annotationView.annotation.coordinate;
NSLog(@"Pin dropped at %f,%f", droppedAt.latitude, droppedAt.longitude);
}
}
编辑4:
Annotaion.m
@dynamic startAddr;
Annotaion.m @dynamic startAddr;
- (CLLocationCoordinate2D)coordinate
{
coordinate.latitude = [self.startAddr.latitude doubleValue];
coordinate.longitude = [self.startAddr.longitude doubleValue];
return coordinate;
}
- (void)setCoordinate:(CLLocationCoordinate2D)newCoordinate {
//I need to update the self.startAddr.latitude and longitude here. Problem solved.
self.startAddr.latitude = [NSNumber numberWithDouble:newCoordinate.latitude];
self.startAddr.longitude = [NSNumber numberWithDouble:newCoordinate.longitude];
coordinate = newCoordinate;
}
推荐答案
首先你需要创建一个这样的自定义注释:
First you have to create a custom annotation like this:
MyAnnotation.h
#import <MapKit/MapKit.h>
@interface MyAnnotation : NSObject <MKAnnotation>{
CLLocationCoordinate2D coordinate;
}
- (id)initWithCoordinate:(CLLocationCoordinate2D)coord;
- (void)setCoordinate:(CLLocationCoordinate2D)newCoordinate;
@end
MyAnnotation.m
#import "MyAnnotation.h"
@implementation MyAnnotation
@synthesize coordinate;
- (NSString *)subtitle{
return nil;
}
- (NSString *)title{
return nil;
}
-(id)initWithCoordinate:(CLLocationCoordinate2D)coord {
coordinate=coord;
return self;
}
-(CLLocationCoordinate2D)coord
{
return coordinate;
}
- (void)setCoordinate:(CLLocationCoordinate2D)newCoordinate {
coordinate = newCoordinate;
}
@end
之后,你只需拥有使用这样的注释:
After that, you just have to use your annotation like this:
// Assuming you have imported MyAnnotation.h and you have a self.map property pointing to a MKMapView
MyAnnotation *myPin = [[MyAnnotation alloc] initWithCoordinate:self.map.centerCoordinate]; // Or whatever coordinates...
[self.map addAnnotation:myPin];
此外,您还必须返回注释的视图。您可以这样做:
Also, you have to return a view for your annotation. You can do so like this:
- (MKAnnotationView *) mapView: (MKMapView *) mapView viewForAnnotation: (id<MKAnnotation>) annotation {
MKPinAnnotationView *pin = (MKPinAnnotationView *) [self.map dequeueReusableAnnotationViewWithIdentifier: @"myPin"];
if (pin == nil) {
pin = [[[MKPinAnnotationView alloc] initWithAnnotation: annotation reuseIdentifier: @"myPin"] autorelease]; // If you use ARC, take out 'autorelease'
} else {
pin.annotation = annotation;
}
pin.animatesDrop = YES;
pin.draggable = YES;
return pin;
}
然后,一旦你采用了 MKMapViewDelegate 控制器中的code>协议,你拖动它后抓住一个引脚的坐标如下:
Then, once you have adopted the MKMapViewDelegate
protocol in your controller, you grab the coordinates of a pin after dragging it like this:
- (void)mapView:(MKMapView *)mapView
annotationView:(MKAnnotationView *)annotationView
didChangeDragState:(MKAnnotationViewDragState)newState
fromOldState:(MKAnnotationViewDragState)oldState
{
if (newState == MKAnnotationViewDragStateEnding)
{
CLLocationCoordinate2D droppedAt = annotationView.annotation.coordinate;
NSLog(@"Pin dropped at %f,%f", droppedAt.latitude, droppedAt.longitude);
}
}
这篇关于在地图视图上拖动注释引脚的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!