MKMapView 不刷新注释

Question

我有一个 MKMapView（显然），它显示用户周围的住房位置。

我有一个半径工具，当进行选择时，注释应根据用户周围的距离添加/删除。

我可以很好地添加/删除，但由于某种原因，注释在我放大或缩小之前不会显示。

这是根据距离添加/删除注释的方法。我尝试了该方法的两种不同变体。

1. 将新注释添加到数组，然后通过 [mapView addAnnotations:NSArray] 添加到地图。

2. 使用 [mapView addAnnotation:MKMapAnnotation] 添加找到的注释；

---

1.

- (void)updateBasedDistance:(NSNumber *)distance {

    //Setup increment for HUD animation loading
    float hudIncrement = ( 1.0f / [[[[self appDelegate] rssParser]rssItems] count]);

    //Remove all the current annotations from the map
    [self._mapView removeAnnotations:self._mapView.annotations];

    //Hold all the new annotations to add to map
    NSMutableArray *tempAnnotations;

    /* 
     I have an array that holds all the annotations on the map becuase 
     a lot of filtering/searching happens. So for memory reasons it is
     more efficient to load annoations once then add/remove as needed.
    */
    for (int i = 0; i < [annotations count]; i++) {

        //Current annotations location
        CLLocation *tempLoc = [[CLLocation alloc] initWithLatitude:[[annotations objectAtIndex:i] coordinate].latitude longitude:[[annotations objectAtIndex:i] coordinate].longitude];

        //Distance of current annotaiton from user location converted to miles
        CLLocationDistance miles = [self._mapView.userLocation.location distanceFromLocation:tempLoc] * 0.000621371192;

        //If distance is less than user selection, add it to the map. 
        if (miles <= [distance floatValue]){
            if (tempAnnotations == nil)
                tempAnnotations = [[NSMutableArray alloc] init];
            [tempAnnotations addObject:[annotations objectAtIndex:i]];
        }

        //For some reason, even with ARC, helps a little with memory consumption
        tempLoc = nil;

        //Update a progress HUD I use. 
        HUD.progress += hudIncrement;
    }

    //Add the new annotaitons to the map
    if (tempAnnotations != nil)
        [self._mapView addAnnotations:tempAnnotations];
}

2.

- (void)updateBasedDistance:(NSNumber *)distance {

    //Setup increment for HUD animation loading
    float hudIncrement = ( 1.0f / [[[[self appDelegate] rssParser]rssItems] count]);

    //Remove all the current annotations from the map
    [self._mapView removeAnnotations:self._mapView.annotations];

    /* 
     I have an array that holds all the annotations on the map becuase 
     a lot of filtering/searching happens. So for memory reasons it is
     more efficient to load annoations once then add/remove as needed.
    */
    for (int i = 0; i < [annotations count]; i++) {

        //Current annotations location
        CLLocation *tempLoc = [[CLLocation alloc] initWithLatitude:[[annotations objectAtIndex:i] coordinate].latitude longitude:[[annotations objectAtIndex:i] coordinate].longitude];

        //Distance of current annotaiton from user location converted to miles
        CLLocationDistance miles = [self._mapView.userLocation.location distanceFromLocation:tempLoc] * 0.000621371192;

        //If distance is less than user selection, add it to the map. 
        if (miles <= [distance floatValue])
            [self._mapView addAnnotation:[annotations objectAtIndex:i]];

        //For some reason, even with ARC, helps a little with memory consumption
        tempLoc = nil;

        //Update a progress HUD I use. 
        HUD.progress += hudIncrement;
    }
}

---

我也在上述方法的末尾尝试过：

[self._mapView setNeedsDisplay];
[self._mapView setNeedsLayout];

另外，强制刷新（在某个地方看到它可能有效）：

self._mapView.showsUserLocation = NO;
self._mapView.showsUserLocation = YES;

非常感谢任何帮助，并且一如既往，感谢您花时间阅读。

Answer 1

我猜测 updateBasedDistance: 是从后台线程调用的。检查 NSLog(@"我在 UI 线程中吗？ %d", [NSThread isMainThread]);。如果它是 0，那么您应该将 removeAnnotations: 和 addAnnotation: 移动到 performSelectorOnMainThread: 调用，或者使用GCD 在主线程上阻塞。