添加自定義註釋，然後應用程序崩潰 - ios

Question

我已經使用這行代碼添加多於自定義註釋MkMapView。然後首先收到內存警告和應用程序崩潰。

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

    if([annotation isKindOfClass:[MKUserLocation class]]) 
    { 
     return nil; 
    } 
    //MKAnnotationView *annotationView = nil; 
    else if ([annotation isKindOfClass:[MyAnnotation class]]) 
    { 
     MKAnnotationView *annotationView = nil; 
     static NSString *identifier = @"identifier"; 
     annotationView = (MKAnnotationView *)[mapViewForMapScreen dequeueReusableAnnotationViewWithIdentifier:identifier]; 
     if (annotationView) { 
      annotationView.annotation = annotation; 
     } else { 
      annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:identifier]; 
      annotationView.canShowCallout = YES; 
     } 

     MyAnnotation *anno=(MyAnnotation*)annotation; 
     tagForAnnotation=(int)anno.tag; 

     if (arrayForLatLong.count!=0) 
     { 
      if ([[[arrayForLatLong valueForKey:@"sourceType"] objectAtIndex:tagForAnnotation] isEqualToString:@"INSTAGRAM"]) 
      { 
       annotationView.image=[UIImage imageNamed:@"instagram.png"]; 
       annotationView.frame=CGRectMake(0, 0, 16, 22); 
      } 
      else if([[[arrayForLatLong valueForKey:@"sourceType"] objectAtIndex:tagForAnnotation] isEqualToString:@"TWITTER"]) 
      { 
       annotationView.image=[UIImage imageNamed:@"twt_pin.png"]; 
       annotationView.frame=CGRectMake(0, 0, 16, 22); 
      } 

      else if ([[[arrayForLatLong valueForKey:@"sourceType"] objectAtIndex:tagForAnnotation] isEqualToString:@"YOUTUBE"]) 
      { 
       annotationView.image=[UIImage imageNamed:@"youtube.png"]; 
       annotationView.frame=CGRectMake(0, 0, 16, 22); 
      } 
      else if ([[[arrayForLatLong valueForKey:@"sourceType"] objectAtIndex:tagForAnnotation] isEqualToString:@"MEETUP"]) 
      { 
       annotationView.image=[UIImage imageNamed:@"meetup_iphone"]; 
       annotationView.frame=CGRectMake(0, 0, 16, 22); 
      } 
      else if ([[[arrayForLatLong valueForKey:@"sourceType"] objectAtIndex:tagForAnnotation] isEqualToString:@"FLICKR"]) 
      { 
       annotationView.image=[UIImage imageNamed:@"flikr.png"]; 
       annotationView.frame=CGRectMake(0, 0, 16, 22); 
      } 
      else if ([[[arrayForLatLong valueForKey:@"sourceType"] objectAtIndex:tagForAnnotation] isEqualToString:@"VK"]) 
      { 
       annotationView.image=[UIImage imageNamed:@"vk1"]; 
       annotationView.frame=CGRectMake(0, 0, 16, 22); 
      } 
     } 
     infoButton=[[AsyncImageView alloc]init]; 
     if ([[[[[arrayForLatLong objectAtIndex:tagForAnnotation] valueForKey:@"user"] valueForKey:@"profilePic"] valueForKey:@"small"] isEqualToString:@""]){ 
      if ([[[[[arrayForLatLong objectAtIndex:tagForAnnotation] valueForKey:@"user"] valueForKey:@"profilePic"] valueForKey:@"medium"] isEqualToString:@""]){ 
       if ([[[[[arrayForLatLong objectAtIndex:tagForAnnotation] valueForKey:@"user"] valueForKey:@"profilePic"] valueForKey:@"large"] isEqualToString:@""]) { 
        [infoButton setImage:[UIImage imageNamed:@"profile"] forState:UIControlStateNormal]; 
       }else{ 
        [infoButton setImageURL:[NSURL URLWithString:[[[[arrayForLatLong objectAtIndex:tagForAnnotation] valueForKey:@"user"] valueForKey:@"profilePic"] valueForKey:@"large"]]]; 
       } 
      }else{ 
       [infoButton setImageURL:[NSURL URLWithString:[[[[arrayForLatLong objectAtIndex:tagForAnnotation] valueForKey:@"user"] valueForKey:@"profilePic"] valueForKey:@"medium"]]]; 
      } 
     }else{ 
      [infoButton setImageURL:[NSURL URLWithString:[[[[arrayForLatLong objectAtIndex:tagForAnnotation] valueForKey:@"user"]valueForKey:@"profilePic"] valueForKey:@"small"]]]; 
     } 
     [infoButton setFrame:CGRectMake(20,10,30,30)]; 
     infoButton.layer.cornerRadius=infoButton.frame.size.height/2.0; 
     infoButton.layer.masksToBounds = YES; 
     [infoButton addTarget:self action:@selector(actionForProfileImage:) forControlEvents:UIControlEventTouchUpInside]; 
     infoButton.layer.borderWidth=1.0; 
     infoButton.layer.borderColor=[UIColor grayColor].CGColor; 
     infoButton.tag=tagForAnnotation; 


     //Followed Button:---- 
     AsyncImageView *followedBtn=[[AsyncImageView alloc]init]; 
     [followedBtn setFrame:CGRectMake(2,8,17,17)]; 
     followedBtn.tag=tagForAnnotation; 
     if ([[[[arrayForLatLong objectAtIndex:tagForAnnotation] valueForKey:@"user"] valueForKey:@"isFollowed"] boolValue]==0){ 
      [followedBtn setBackgroundImage:[UIImage imageNamed:@"star_grey.png"] forState:UIControlStateNormal]; 
     }else{ 
      [followedBtn setBackgroundImage:[UIImage imageNamed:@"star_blue.png"] forState:UIControlStateNormal]; 
     } 
     [followedBtn addTarget:self action:@selector(actionForStarImage:) forControlEvents:UIControlEventTouchUpInside]; 
     UIView*viewForCallOut=[[UIView alloc] initWithFrame:CGRectMake(0, 0,50, 50)]; 
     [viewForCallOut addSubview:infoButton]; 
     //[viewForCallOut addSubview:followedBtn]; 
     annotationView.leftCalloutAccessoryView=viewForCallOut; 
     annotationView.canShowCallout = YES; 
     return annotationView; 
    } 


    return nil; 
} 

請檢查我的代碼，如果我做了任何錯誤，請讓我知道。 在此先感謝

Answer 1

當您有大量的數據點導致大量的註釋時，一個好方法是聚集數據點併爲每個羣集添加一個註釋。在地圖放大到一個集羣中時，用集羣中數據點的註釋替換表示集羣的註釋。在縮小集羣時，可以用代表集羣的註釋替換表示數據點的註釋。這種方法減少了註釋的總數，並使數據更易於理解。 This SO question和this post會給你更多關於聚類的信息。