Question

我有一个应用程序，它在MapView中显示大约100个注释（带有自定义图钉图像，标注附件和注释图像）。在构建注释时，我存储了注释和构建之间的链接，因此我可以分配正确的构建并在之后打开正确的segue。

在iOS 6中，它们构建得非常快，我还在添加它们的同时启用了动画，因此一个引脚在另一个引脚之后被丢弃，但是在iOS7中使用苹果地图这是不可能的（？）。现在，在我的iPhone 4S上构建这100个注释需要1秒钟，这太长了。反正有没有改进代码？

- (void)viewDidLoad

...

//creating annotations
    annotationlink = [[NSMutableArray alloc] init];

    for (int i = 0; i < data.count; i++) {
        NSDictionary *dataItem = [data objectAtIndex:i];

        //storing annotation in array for link
        Annotation *buildingannotation = [[Annotation alloc] init];
        NSNumber *index = [NSNumber numberWithInteger:i];
        NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:index, indexKey, buildingannotation, annotationKey, nil];
        [annotationlink addObject:dict];

        buildingannotation.title = [dataItem objectForKey:@"Building"];
        buildingannotation.subtitle = [dataItem objectForKey:@"Info"];

        MKCoordinateRegion buildingcoordinates;
        buildingcoordinates.center.latitude = [[dataItem objectForKey:@"Latitude"] floatValue];
        buildingcoordinates.center.longitude = [[dataItem objectForKey:@"Longitude"] floatValue];
        buildingannotation.coordinate = buildingcoordinates.center;

        [self.mapView addAnnotation:buildingannotation];
    }


- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
{
    if ([annotation isKindOfClass:[MKUserLocation class]]){
        return nil;
    }

    MKAnnotationView *pinView = (MKAnnotationView *)
    [self.mapView dequeueReusableAnnotationViewWithIdentifier:pinIdentifier];

    MKAnnotationView *customAnnotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:pinIdentifier];
    customAnnotationView.canShowCallout = YES;

    //right button to detail view
    UIButton* disclosureButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
    customAnnotationView.rightCalloutAccessoryView = disclosureButton;

    //left button for image
    NSInteger *buildingindex = [self getIndex:annotation];
    NSDictionary *dataItem = [data objectAtIndex:buildingindex];
    NSString* filename = [dataItem objectForKey:@"Thumb"];
    filename = [filename stringByAppendingString:@"@2x.jpg"];

    NSString* resourceimagePath = [resourcePath stringByAppendingPathComponent:filename];
    Image = [UIImage imageWithContentsOfFile:resourceimagePath];

    UIImageView *AnnotationThumb = [[UIImageView alloc] initWithImage:Image];
    AnnotationThumb.frame = CGRectMake(0, 0, 31, 31);
    customAnnotationView.leftCalloutAccessoryView = AnnotationThumb;

    //annotation image
    customAnnotationView.image = [UIImage imageNamed:@"Annotation_white.png"];

    return customAnnotationView;
    return pinView;
}

以下函数使用nspredicate获取当前注释的索引，以使用字典过滤数组。这样做的好处是，我可以在calloutAccessoryControlTapped时使用它：

-(NSInteger*) getIndex:(Annotation*)searchannotation
{
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%K == %@", annotationKey, searchannotation];
    NSArray *filteredarray = [annotationlink filteredArrayUsingPredicate:predicate];
    NSDictionary *building = [filteredarray objectAtIndex:0];
    NSInteger *buildingIndex = [[building objectForKey:indexKey] integerValue];
    return buildingIndex;
}

使用iPhone 4S后，最后一个引脚在视图加载后1.14秒内构建。

如果我手动搜索注释链接数组而不是像这样使用nspredicate函数：

//left button for image
    int buildingIndex;
    for (int i = 0; i < annotationlink.count; i++) {
        NSDictionary *annotationDict = [annotationlink objectAtIndex:i];
        if ([[annotationDict objectForKey:annotationKey] isEqual:annotation]) {
            buildingIndex= [[annotationDict objectForKey:indexKey] integerValue];
            i = annotationlink.count;
        }
    }

    NSDictionary *dataItem = [data objectAtIndex:buildingIndex];

日志表示最后一个引脚是在viewDidLoad之后1.89秒构建的。

如果我在viewDidApper而不是viewDidLoad中创建注释，View会立即显示，但背景需要一些时间才能加载，所以直到引脚掉落一切都是灰色的，这也不是很好......

Answer 1

谢谢安娜的建议！我实现了这样的改进：

<强> Annotation.h：

#import <MapKit/MKAnnotation.h> 

@interface Annotation : NSObject <MKAnnotation> {} 
@property(nonatomic, assign) CLLocationCoordinate2D coordinate; 
@property(nonatomic, copy) NSString *title; 
@property(nonatomic, copy) NSString *subtitle; 
@property NSInteger *ID; 
@end

Annotation.m：

#import "Annotation.h" 

@implementation Annotation 
@synthesize coordinate, title, subtitle, ID; 
@end

ViewDidAppear：

//creating annotations 
for (int i = 0; i < data.count; i++) { 
   NSDictionary *dataItem = [data objectAtIndex:i]; 
   Annotation *buildingannotation = [[Annotation alloc] init]; 
   buildingannotation.ID = i; 
   buildingannotation.title = [dataItem objectForKey:@"Building"]; 
   buildingannotation.subtitle = [dataItem objectForKey:@"Subtitle"]; 

   MKCoordinateRegion buildingcoordinates; 
   buildingcoordinates.center.latitude = [[dataItem objectForKey:@"Latitude"] floatValue];    
   buildingcoordinates.center.longitude = [[dataItem objectForKey:@"Longitude"] floatValue]; 
   buildingannotation.coordinate = buildingcoordinates.center; 

   [self.mapView addAnnotation:buildingannotation]; 
}

viewForAnnotation：

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
{
    if ([annotation isKindOfClass:[MKUserLocation class]]){
        return nil;
}

MKAnnotationView *pinView = (MKAnnotationView *)
[self.mapView dequeueReusableAnnotationViewWithIdentifier:pinIdentifier];

if (pinView == nil) {
    MKAnnotationView *customAnnotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:pinIdentifier];
    customAnnotationView.canShowCallout = YES;

    //right button to detail view
    UIButton* disclosureButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
    customAnnotationView.rightCalloutAccessoryView = disclosureButton;

    //left button for image
    Annotation *buildingAnnotation = (Annotation *)annotation;
    NSInteger *buildingindex = buildingAnnotation.ID;

    NSString *filePath = [thumbname objectAtIndex:buildingindex];
    UIImageView *AnnotationThumb = [[UIImageView alloc] initWithImage:[UIImage imageWithContentsOfFile:filePath]];
    AnnotationThumb.frame = CGRectMake(0, 0, 31, 31);
    customAnnotationView.leftCalloutAccessoryView = AnnotationThumb;

    //annotation image
    customAnnotationView.image = [UIImage imageNamed:@"Annotation_white.png"];

    return customAnnotationView;
} else {
    pinView.annotation = annotation;
}

return pinView;
}

标注：

- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view calloutAccessoryControlTapped:(UIControl *)control
{
    Annotation *buildingAnnotation = (Annotation *)view.annotation;
    selectedbuilding = buildingAnnotation.ID;
    [self performSegueWithIdentifier:@"DetailViewController" sender:self];
}

还需要一些时间来显示所有注释。有没有机会进一步改进代码？

Answer 2

我更新了关于Anna的回复和PhotosByLocation Sample Application的vievForAnnotation功能。它现在有效，我希望它是实现重用的正确方法......

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
{
    if ([annotation isKindOfClass:[MKUserLocation class]]){
        return nil;
    }

    MKAnnotationView *buildingAnnotationView = (MKAnnotationView *) [mapView dequeueReusableAnnotationViewWithIdentifier:pinIdentifier];

    if (buildingAnnotationView) {
        [buildingAnnotationView prepareForReuse];
    } else {
        buildingAnnotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:pinIdentifier];
        buildingAnnotationView.canShowCallout = YES;

        //right button to detail view
        UIButton* disclosureButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
        buildingAnnotationView.rightCalloutAccessoryView = disclosureButton;

        //annotation image
        buildingAnnotationView.image = [UIImage imageNamed:@"Annotation_white.png"];
    }

    //left button for image
    Annotation *buildingAnnotation = (Annotation *)annotation;
    NSInteger *buildingindex = buildingAnnotation.ID;

    NSString *filePath = [thumbname objectAtIndex:buildingindex];
    UIImageView *AnnotationThumb = [[UIImageView alloc] initWithImage:[UIImage imageWithContentsOfFile:filePath]];
    AnnotationThumb.frame = CGRectMake(0, 0, 31, 31);
    buildingAnnotationView.leftCalloutAccessoryView = AnnotationThumb;

    return buildingAnnotationView;
}

构建MapView注释非常慢

2 个答案: