iPhone-在mapkit中更新注释字幕 [英] iPhone - Updating Annotation subtitle in mapkit

问题描述

我有一个带有标题和副标题的自定义地标.字幕实际上是使用反向地址解析器显示掉线引脚的地址.

I have a custom placemark with title and subtitle. The subtitle is actually displaying the address of the dropped pin using the reverse geocoder.

我有一个按钮，该按钮具有可将图钉放下的动作.此操作将获取用户的位置坐标，然后调用[geocoder start]，后者会使用反向Geocoder获取完整地址，并生成自定义注释，然后调用[mapView addAnnotation:customPlacemark].

I have a button which has an action to drop the pin. This action gets the location coordinates of the user, and then calls [geocoder start] which gets the full address with Reverse Geocoder and generates the custom annotation and then calls [mapView addAnnotation:customPlacemark].

我的问题是，使用此顺序，当没有WiFi连接(只有3G或Edge)时，该引脚会掉落很多，因为它会想获取反向地理编码信息.

My problem is that using this sequence order, when there's no a WiFi connection (only 3G or maybe Edge) the pin takes a lot to drop because it's watigin to get the reverse geocoding info.

所以基本上，我需要不带字幕的情况下放下大头针，然后从viewDidAnnotation调用地理编码器，并在reverseGeocoder内部更新字幕，但是我不确定如何做到这一点.

So basically I need to drop the pin without a subtitle and from the viewDidAnnotation call the geocoder and inside the reverseGeocoder update the subtitle but I'm not sure how to do that.

我想显示不带地址详细信息的注释，并在从反向地址解析器获取信息时对其进行更新.

I want to display the annotation without the address details and update it when it gets the information from the reverse geocoder.

有什么建议吗?

预先感谢

推荐答案

MKMapView通过KVO观察其注释的更改.因此，如果您以符合KVO的方式更新注释的属性，则它应该可以正常工作.

MKMapView observes changes its annotations via KVO. Therefore if you update your annotation's properties in a KVO compliant manner, it should Just Work.

例如，当反向地址解析器返回注释的地址时，您首先宣布title和subtitle属性即将更改:

For example, when the reverse geocoder returns an address for your annotation, you first announce the title and subtitle properties are about to change:

[self willChangeValueForKey:@"title"];
[self willChangeValueForKey:@"subtitle"];

请注意，上面的代码被假定为在注释类中.

Note that the above code is assumed to be in the annotation class.

然后使用地理编码器中的信息更新注释.完成后:

Then update the annotation with information from the geocoder. When you are done:

[self didChangeValueForKey:@"subtitle"];
[self didChangeValueForKey:@"title"];

请注意didChangeValueForKey:的顺序已更改，因为它们需要正确嵌套，有点像HTML标记.

Note the order changed for didChangeValueForKey: as these need to be nested properly, somewhat like HTML tags.

这对于coordinate属性也适用，这将导致销移动.

This also works for the coordinate property, that will cause the pin to move.

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