在地图视图中重新加载注释

Question

我将注释作为硬编码值添加到方法中

- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation

     CLLocationCoordinate2D coords1;
     coords1.latitude = 40.579754;
     coords1.longitude = -120.1303229;

     MKPointAnnotation *annotationPoint1 = [[MKPointAnnotation alloc] init];
     annotationPoint1.coordinate = coords1;
     annotationPoint1.title = @"TJ11234";
     annotationPoint1.subtitle = @"Power Failure \n Start Time:12hrs 30min \n End Time:14hrs ";

     [self.mapView addAnnotation:annotationPoint1];

带有经度和纬度硬编码的值，其初始加载效果很好，但是当我转到另一页并返回该页面时，注释未加载。 我该怎么做才能纠正它？

Answer 1

每当地图视图收到新的位置更新时，都会调用mapView:didUpdateUserLocation: 检查文档 。

如果要在显示地图时设置注释，可以将代码放置在viewDidAppear或类似文件中。

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated]

    CLLocationCoordinate2D coords1;
    coords1.latitude = 40.579754;
    coords1.longitude = -120.1303229;

    MKPointAnnotation *annotationPoint1 = [[MKPointAnnotation alloc] init];
    annotationPoint1.coordinate = coords1;
    annotationPoint1.title = @"TJ11234";
    annotationPoint1.subtitle = @"Power Failure \n Start Time:12hrs 30min \n End Time:14hrs ";

    [self.mapView addAnnotation:annotationPoint1];
}

希望这可以帮助。