iOS根据地址在地图上展示坐标

遇到一个需求，给出起点和终点的位置，需要在地图中展示出来，并有导航功能。
首先需要把位置转化成经纬度，这个可以使用系统提供的方法，需要引入框架#import <MapKit/MapKit.h>，

    // address为具体地址名称
    NSString *address;
    [myGeocoder geocodeAddressString:oreillyAddress completionHandler:^(NSArray<CLPlacemark *> * _Nullable placemarks, NSError * _Nullable error) {
        if ([placemarks count] > 0 && error == nil) {
            CLPlacemark *firstPlacemark = [placemarks objectAtIndex:0];
            // coord即为得到到坐标
            CLLocationCoordinate2D coord;
            coord.latitude = firstPlacemark.location.coordinate.latitude;
            coord.longitude = firstPlacemark.location.coordinate.longitude;
            // 由于项目中使用到是百度地图，需要把坐标转化为百度地图到坐标
            CLLocationCoordinate2D baiduCoor;
            baiduCoor = [self changeBaiDuGPS:coord];
        } else if ([placemarks count] == 0 && error == nil) {
            NSLog(@"Found no placemarks.");
        } else if (error != nil) {
            NSLog(@"An error occurred = %@", error);
        }
    }];

    // 坐标转化方法
    - (CLLocationCoordinate2D)changeBaiDuGPS:(CLLocationCoordinate2D)coor {
    //转换国测局坐标（google地图、soso地图、aliyun地图、mapabc地图和amap地图所用坐标）至百度坐标
    NSDictionary* testdic = BMKConvertBaiduCoorFrom(coor,BMK_COORDTYPE_COMMON);
    //转换后的百度坐标
    CLLocationCoordinate2D baiduCoor = BMKCoorDictionaryDecode(testdic);
    
    return baiduCoor;
    }

同样通过上面的方法可以得到起始点的坐标和终点的坐标，把坐标展示到地图上：

    startPoint = [[BMKPointAnnotation alloc] init];
    startPoint.coordinate = startCoor;
    [_mapView addAnnotation:startPoint];

    endPoint = [[BMKPointAnnotation alloc] init];
    endPoint.coordinate = endCoor;
    [_mapView addAnnotation:endPoint];

大头针已经添加到地图上了，下面需要自定义大头针的样式，需要添加百度地图代理_mapView.delegate = self;：

// BMKMapViewDelegate
- (BMKAnnotationView *)mapView:(BMKMapView *)mapView viewForAnnotation:(id<BMKAnnotation>)annotation {
    if (annotation == startPoint) {
        NSString *AnnotationViewID = @"renameMark";
        BMKAnnotationView *annotationView = (BMKAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:AnnotationViewID];
        annotationView.frame = CGRectMake(0, 0, 30, 30);
        
        if (annotationView == nil) {
            annotationView = [[BMKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:AnnotationViewID];
            annotationView.image = [UIImage imageNamed:@"map_start"];
        }
        return annotationView;
    } else if (annotation == endPoint) {
        NSString *AnnotationViewID = @"renameMark";
        BMKAnnotationView *annotationView = (BMKAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:AnnotationViewID];
        annotationView.frame = CGRectMake(0, 0, 30, 30);
        if (annotationView == nil) {
            annotationView = [[BMKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:AnnotationViewID];
            annotationView.image = [UIImage imageNamed:@"map_end"];
        }
        return annotationView;
    }
    return nil;
}

自定义大头针样式
页面展示基本上完成了，导航功能需要跳转到相应app就可以，目前我只做了跳转到百度地图和系统自带地图，跳转相应app需要在plist文件中设置
plist文件设置相应选项
跳转选项使用UIAlertController

    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
    [alertController addAction:[UIAlertAction actionWithTitle:@"使用苹果地图" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        [self jumpAppleMap];
    }]];
    
    [alertController addAction:[UIAlertAction actionWithTitle:@"使用百度地图" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        [self jumpBaiduMap];
    }]];
    [alertController addAction: [UIAlertAction actionWithTitle: @"取消" style: UIAlertActionStyleCancel handler:nil]];
    [self presentViewController: alertController animated: YES completion: nil];

跳转到苹果地图，此时使用的坐标为系统根据文字转换的坐标，不必使用百度地图的坐标:

    - (void)jumpAppleMap {
    MKMapItem *startLocation = [[MKMapItem alloc] initWithPlacemark:[[MKPlacemark alloc] initWithCoordinate:iosStartCoor addressDictionary:nil]];
    MKMapItem *toLocation = [[MKMapItem alloc] initWithPlacemark:[[MKPlacemark alloc] initWithCoordinate:iosEndCoor addressDictionary:nil]];
    [MKMapItem openMapsWithItems:@[startLocation, toLocation] launchOptions:@{MKLaunchOptionsDirectionsModeKey: MKLaunchOptionsDirectionsModeDriving, MKLaunchOptionsShowsTrafficKey: [NSNumber numberWithBool:YES]}];
    }

跳转到百度地图，此时需要使用转化后的百度地图坐标:

- (void)jumpBaiduMap {
    if ([[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:@"baidumap://map/"]]) {
        NSString *urlString = [NSString stringWithFormat:@"baidumap://map/direction?origin=%f,%f&destination=%f,%f&&mode=driving",startCoor.latitude,startCoor.longitude,endCoor.latitude,endCoor.longitude];
        NSURL *url = [NSURL URLWithString:urlString];
        
        [[UIApplication sharedApplication] openURL:url options:@{} completionHandler:nil];
    } else {
        // 没有安装百度地图，无法打开
    }
}

这样程序便会跳转到相应APP，并进入到导航功能。