的MKMapView不刷新注解 [英] MKMapView not refreshing annotations

问题描述

我有一个的MKMapView（明显），显示在用户周围房屋地点。

I have a MKMapView (obviously), that shows housing locations around the user.

我有一个半径的工具，当一个选择时，注释应该添加/根据各地用户的距离删除。

I have a Radius tool that when a selection is made, the annotations should add/remove based on distance around the user.

我把它添加/删除罚款，但由于某些原因，注释不会出现，直到我放大或缩小。

I have it add/removing fine but for some reason the annotations won't show up until I zoom in or out.

这是添加方法/删除基于距离的注释。我曾尝试该方法的两个不同的变化。

This is the method that adds/removes the annotations based on distance. I have tried two different variations of the method.

1. 添加新的注释到一个数组，然后通过添加到地图[MapView的addAnnotations：NSArray的。

添加注解，因为它使用它们找到 [图形页面addAnnotation：MKMapAnnotation] ;

Add the annotations as it finds them using [mapView addAnnotation:MKMapAnnotation];

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;
    }
}

---

我也试图在上述方法的末尾：

---

I have also attempted at the end of the above method:

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

此外，强制刷新（看到的地方它可能工作）：

Also, to force a refresh (saw somewhere it might work):

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

任何帮助将非常AP preciated和往常一样，感谢您抽出时间来阅读。

Any help would be very much appreciated and as always, thank you for taking the time to read.

推荐答案

我要猜 updateBasedDistance：会从后台线程调用。请与的NSLog（@我是在UI线程％d个？[NSThread isMainThread]）; 。如果是 0 ，那么你应该移动 removeAnnotations：和 addAnnotation：到 performSelectorOnMainThread：调用，或在主线程GCD块

I'm going to guess that updateBasedDistance: gets called from a background thread. Check with NSLog(@"Am I in the UI thread? %d", [NSThread isMainThread]);. If it's 0, then you should move the removeAnnotations: and addAnnotation: to a performSelectorOnMainThread: invocation, or with GCD blocks on the main thread.

这篇关于的MKMapView不刷新注解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！