objective-c - ios: MapView Pin 颜色注释不断变化；为什么？

Question

您好，感谢您的帮助。

我正在使用以下代码在我的 MapView 注释上设置图钉颜色？

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation {




    MKPinAnnotationView *pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:@"pinView"];
    if (!pinView) {

        //////////////
        pinView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"pinView"];
        pinView.pinColor = MKPinAnnotationColorGreen;
        if([[annotation title] isEqualToString:@"MuRoom"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorRed;

            NSLog( @"data from ann index %@", annTile);
        }
        if([[annotation title] isEqualToString:@"Mike's"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorRed;

            NSLog( @"data from ann index %@", annTile);
        }
        if([[annotation title] isEqualToString:@"Bill's"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorPurple;

            NSLog( @"data from ann index %@", annTile);
        }
        if([[annotation title] isEqualToString:@"Steve's"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorGreen;

            NSLog( @"data from ann index %@", annTile);
        }
        if([[annotation title] isEqualToString:@"Louisa's"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorGreen;

            NSLog( @"data from ann index %@", annTile);
        }


        pinView.animatesDrop = YES;
        pinView.canShowCallout = YES;

        UIButton *rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
        pinView.rightCalloutAccessoryView = rightButton;
    } else {
        pinView.annotation = annotation;
    }
    return pinView;
}


I am then using the function below to filter my pins locaions



-(void)FilterAddAll:(id)sender
{
    [mapview removeAnnotations:annoArra];
    [mapview removeAnnotations:annoArrayVenue];
 [mapview removeAnnotations:artArray];


//    CLLocationCoordinate2D center = mapview.centerCoordinate;
//    mapview.centerCoordinate = center;


    [mapview addAnnotations:annoArra];
    [mapview addAnnotations:annoArrayVenue];
    [mapview addAnnotations:artArray];

}

-(void)FilterArt:(id)sender
{
    [mapview removeAnnotations:annoArra];
    [mapview removeAnnotations:artArray];
    [mapview removeAnnotations:annoArrayVenue];

    [mapview addAnnotations:annoArra];
}

-(void)FilterVenue:(id)sender
{
    [mapview removeAnnotations:annoArra];
    [mapview removeAnnotations:artArray];
    [mapview removeAnnotations:annoArrayVenue];

    [mapview addAnnotations:artArray];
}

问题：如何让引脚颜色保持原来的颜色？在我过滤后，它们会作为随机的 pin 颜色返回。

再次感谢。

Answer 1

发生这种情况是因为您没有正确使用“reuseIdentifier”。当您从 dequeueReusableAnnotationViewWithIdentifier:@"pinView" 取回 pin 时，您需要：

始终设置引脚颜色，或者为每个彩色引脚使用不同的重用标识符

即，您可能会得到一个带有红色引脚的可重用视图，并且您想显示一个蓝色引脚

例子：

MKPinAnnotationView *pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:@"pinView"];
    if (!pinView) {

        //////////////
        pinView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"pinView"];

        pinView.animatesDrop = YES;
        pinView.canShowCallout = YES;

        UIButton *rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
        pinView.rightCalloutAccessoryView = rightButton;
    } else {
        pinView.annotation = annotation;
    }

// SET THE PIN COLOR REGARDLESS OF WHETHER A REUSABLE ANNOTATION WAS RETURNED OR NOT

        pinView.pinColor = MKPinAnnotationColorGreen;
        if([[annotation title] isEqualToString:@"MuRoom"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorRed;

            NSLog( @"data from ann index %@", annTile);
        }
        if([[annotation title] isEqualToString:@"Mike's"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorRed;

            NSLog( @"data from ann index %@", annTile);
        }
        if([[annotation title] isEqualToString:@"Bill's"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorPurple;

            NSLog( @"data from ann index %@", annTile);
        }
        if([[annotation title] isEqualToString:@"Steve's"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorGreen;

            NSLog( @"data from ann index %@", annTile);
        }
        if([[annotation title] isEqualToString:@"Louisa's"])
        {
            // Do somethingMKAnnotation
            pinView.pinColor = MKPinAnnotationColorGreen;

            NSLog( @"data from ann index %@", annTile);
        }