在xcode中将不同的图像添加到不同的注释视图 [英] Adding different images to different annotation views in xcode

问题描述

我正在尝试将不同的图像添加到不同的注释视图，换句话说，我想要一个唯一的图片对应于每个唯一的图钉.这是我正在尝试的:

I am trying to add different images to different annotation views, in other words, i want a unique pic to correspond to each unique pin. Here is what I am trying:

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
{
    NSLog(@"welcome into the map view annotation");

    // if it's the user location, just return nil.
    if ([annotation isKindOfClass:[MKUserLocation class]])
        return nil;

    // try to dequeue an existing pin view first
    static NSString* AnnotationIdentifier = @"AnnotationIdentifier";
    MKPinAnnotationView* pinView = [[[MKPinAnnotationView alloc]
                                     initWithAnnotation:annotation reuseIdentifier:AnnotationIdentifier] autorelease];
    pinView.animatesDrop=YES;
    pinView.canShowCallout=YES;
    pinView.pinColor=MKPinAnnotationColorPurple;


    UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
    [rightButton setTitle:annotation.title forState:UIControlStateNormal];
    [rightButton addTarget:self
                    action:@selector(showDetails:)
          forControlEvents:UIControlEventTouchUpInside];
    pinView.rightCalloutAccessoryView = rightButton;

    if (CLLocationCoordinate2D == theCoordinate1) {

    UIImageView *profileIconView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Jeff.png"]];
    pinView.leftCalloutAccessoryView = profileIconView;
    [profileIconView release];

    }else if(CLLocationCoordinate2D = theCoordinate2) {
        UIImageView *profileIconView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Pierce.png"]];
        pinView.leftCalloutAccessoryView = profileIconView;
        [profileIconView release];
    }

我写的行出现错误

if (CLLocationCoordinate2D == theCoordinate1) {

我不确定什么地方出了问题，也无法找出另一种方法来识别单个注释.任何帮助都将不胜感激！

I am not sure quite what is wrong, nor can i figure out another way to identify the individual annotation. Any help is greatly appreciated!!

推荐答案

该行给出了错误，因为CLLocationCoordinate2D是struct的类型，而theCoordinate1是类型为CLLocationCoordinate2D的变量.您无法将两者进行比较.

That line gives an error because CLLocationCoordinate2D is a type of struct and theCoordinate1 is, I assume, a variable of type CLLocationCoordinate2D. You can't compare the two.

您要尝试做的是将请求其视图的当前注释的坐标与theCoordinate1中的坐标进行比较.为此，如果需要，您需要这样的东西:

What you are trying to do is compare the coordinates of the current annotation for which a view is being requested to the coordinates in theCoordinate1. To do that, if you must, you need something like this:

if ((annotation.coordinate.latitude == theCoordinate1.latitude) 
        && (annotation.coordinate.longitude == theCoordinate1.longitude)) {

但是，即使有时起作用"，我也不建议以这种方式比较浮点数.如果必须比较坐标，请使用CLLocation的distanceFromLocation:方法，查看两者之间的距离是否低于某个阈值，例如10.0米.

However, I don't recommend comparing floating point numbers that way even if it "works" sometimes. If you must compare coordinates, use CLLocation's distanceFromLocation: method and see if the distance between the two is below some threshold like 10.0 meters.

检查注释是否是您正在寻找的另一种方法是保留对注释本身的引用(传递给addAnnotation:方法的注释)，然后可以执行if (annotation == theAnnotation1).

Another way to check if the annotation is the one you're looking for is to keep a reference to the annotation itself (the one you passed to the addAnnotation: method) and then you can do if (annotation == theAnnotation1).

如果您不想保留对注释的引用，也可以检查注释的标题是否是您要查找的标题(if ([annotation.title isEqualToString:@"Jeff"])).

If you don't want to keep a reference to the annotations, you can also check if the title of the annotation is the one your're looking for (if ([annotation.title isEqualToString:@"Jeff"])).

最好的方法是将自定义属性(最好是int)添加到自定义注释类，然后在viewForAnnotation中进行检查.

The best way is to add a custom property (ideally an int) to a custom annotation class and check for that in viewForAnnotation.

其他一些无关的东西:

A few other unrelated things:

• 代替执行addTarget，而是处理地图视图自己的calloutAccessoryControlTapped委托方法中的按钮按下操作，该方法将提供对注释的引用(请参阅dequeueReusableAnnotationViewWithIdentifier重用视图(请参阅 EXC_BAD_ACCESS与例如MKPinAnnotationView .

• Instead of doing addTarget, handle the button press in the map view's own calloutAccessoryControlTapped delegate method which will give a reference to the annotation (see How to find which annotation send showDetails? for example).
• You have a comment to "dequeue" but you're not doing it. It's recommended to use dequeueReusableAnnotationViewWithIdentifier in viewForAnnotation to re-use views (see EXC_BAD_ACCESS with MKPinAnnotationView for example).

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