高德地图上，点击空白处，一定会清除当前selected annotation的选中状态。可以通过记录当前selected annotation，在点击空白处之后，一定会执行didDeselectAnnotationView回调，可在回调中对其状态进行恢复。

custom annoView.h

@property(nonatomic, strong) NSString *imageName;
@property(nonatomic, strong) NSString *selectedImageName;

custom annoView.m重写方法：

- (void)setSelected:(BOOL)selected {
      if (selected == self.isSelected) {
        return;
     }
    [super setSelected:selected];
    if (selected) {
        self.image = [UIImage imageNamed:self.selectedImageName];
    }else {
        self.image = [UIImage imageNamed:self.imageName];
    }
}

viewcontroller.m

/* 起始点经纬度. */
@property (nonatomic) CLLocationCoordinate2D startCoordinate;
/* 终点经纬度. */
@property (nonatomic) CLLocationCoordinate2D destinationCoordinate;

/* 用于显示当前路线方案. */
@property (nonatomic) MANaviRoute * naviRoute;

@property (nonatomic, strong) MAPointAnnotation *startAnnotation;
@property (nonatomic, strong) SPPackageAnotation *destinationAnnotation;

@property (nonatomic, strong) SPPackageAnotation *destinationAnnotation_temp;

- (MAAnnotationView*)mapView:(MAMapView *)mapView viewForAnnotation:(id <MAAnnotation>)annotation {
    
    if ([annotation isKindOfClass:[XXXAnotation class]]) {
        SSSAnnotationView *annoView = (SSSAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:@"PackageID"];
        if (annoView == nil) {
            annoView = [[SSSAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"PackageID"];
        }
        XXXAnotation *packAnno =  (XXXAnotation *)annotation;
        NSString *imageName = @"";
        NSString *selectedImageName = @"";
        if (....) {
            imageName = @"icon_package_green_small";
            selectedImageName = @"icon_package_green_large";
        }else {
            imageName = @"icon_package_red_small";
            selectedImageName = @"icon_package_red_large";
        }
        annoView.imageName = imageName;
        annoView.selectedImageName = selectedImageName;
        ...
        return annoView;
    }else if ([annotation isKindOfClass:[MAPointAnnotation class]]) {
        ...
    }
    return nil;
}

回调方法处理（包含路线规划）

- (void)mapView:(MAMapView *)mapView didSelectAnnotationView:(MAAnnotationView *)view {
    if ([view isKindOfClass:[SSSAnnotationView class]]) {
        self.destinationCoordinate = view.annotation.coordinate;
        self.destinationAnnotation = (XXXAnotation *)view.annotation;
        if (self.startAnnotation != nil) {
            [self clear];//清除路线，参考官方Demo
            [self searchRoutePlanning];//路线规划，参考官方Demo
        }
    }
}
- (void)mapView:(MAMapView *)mapView didDeselectAnnotationView:(MAAnnotationView *)view {
    if ([view isKindOfClass:[SSSAnnotationView class]]) {
        if (self.startAnnotation != nil && self.destinationAnnotation != nil) {
            self.destinationAnnotation_temp = self.destinationAnnotation;
            self.destinationAnnotation = nil;
            [self clear];//清除路线，
            [self redrawRouteAfterDelay];//恢复已选中状态！
        }
    }
}
//恢复已选中状态！
- (void)redrawRouteAfterDelay {
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        if (self.destinationAnnotation == nil) {
            self.destinationAnnotation = self.destinationAnnotation_temp;
            self.destinationCoordinate = self.destinationAnnotation.coordinate;
            //触发回调"- (void)mapView:(..)mapView didSelectAnnotationView:(..)view"
            [_aMapView selectAnnotation:self.destinationAnnotation animated:NO];
        }
    });
}