地理反编码的实现

一：效果

输入经纬度，可以得到相应的地名

二：思路

跟地里编码差不多

1.获取用户输入的经纬度

2.根据用户输入的经纬度创建CLLocation对象

3.根据CLLocation对象获取对应的地标信息

三：代码

<code class="hljs objectivec has-numbering"><span class="hljs-preprocessor">#import <span class="hljs-title">"ViewController.h"</span></span>
<span class="hljs-preprocessor">#import <span class="hljs-title"><CoreLocation/CoreLocation.h></span></span>

<span class="hljs-class"><span class="hljs-keyword">@interface</span> <span class="hljs-title">ViewController</span> ()</span>
<span class="hljs-comment">/**
 *  地理编码对象
 */</span>
<span class="hljs-keyword">@property</span> (<span class="hljs-keyword">nonatomic</span> ,<span class="hljs-keyword">strong</span>) CLGeocoder *geocoder;

<span class="hljs-preprocessor">#pragma mark - 反地理编码</span>
- (<span class="hljs-keyword">IBAction</span>)reverseGeocode;

<span class="hljs-keyword">@property</span> (<span class="hljs-keyword">weak</span>, <span class="hljs-keyword">nonatomic</span>) <span class="hljs-keyword">IBOutlet</span> UITextField *longtitudeField;
<span class="hljs-keyword">@property</span> (<span class="hljs-keyword">weak</span>, <span class="hljs-keyword">nonatomic</span>) <span class="hljs-keyword">IBOutlet</span> UITextField *latitudeField;
<span class="hljs-keyword">@property</span> (<span class="hljs-keyword">weak</span>, <span class="hljs-keyword">nonatomic</span>) <span class="hljs-keyword">IBOutlet</span> <span class="hljs-built_in">UILabel</span> *reverseDetailAddressLabel;

<span class="hljs-keyword">@end</span>

<span class="hljs-class"><span class="hljs-keyword">@implementation</span> <span class="hljs-title">ViewController</span></span>

- (<span class="hljs-keyword">void</span>)reverseGeocode
{
    <span class="hljs-comment">// 1.获取用户输入的经纬度</span>
    <span class="hljs-built_in">NSString</span> *longtitude = <span class="hljs-keyword">self</span><span class="hljs-variable">.longtitudeField</span><span class="hljs-variable">.text</span>;
    <span class="hljs-built_in">NSString</span> *latitude = <span class="hljs-keyword">self</span><span class="hljs-variable">.latitudeField</span><span class="hljs-variable">.text</span>;
    <span class="hljs-keyword">if</span> (longtitude<span class="hljs-variable">.length</span> == <span class="hljs-number">0</span> ||
        longtitude == <span class="hljs-literal">nil</span> ||
        latitude<span class="hljs-variable">.length</span> == <span class="hljs-number">0</span> ||
        latitude == <span class="hljs-literal">nil</span>) {
        <span class="hljs-built_in">NSLog</span>(@<span class="hljs-string">"请输入经纬度"</span>);
        <span class="hljs-keyword">return</span>;
    }

    <span class="hljs-comment">// 2.根据用户输入的经纬度创建CLLocation对象</span>
    CLLocation *location = [[CLLocation alloc] initWithLatitude:[latitude doubleValue]  longitude:[longtitude doubleValue]];

    <span class="hljs-comment">// 3.根据CLLocation对象获取对应的地标信息</span>
    [<span class="hljs-keyword">self</span><span class="hljs-variable">.geocoder</span> reverseGeocodeLocation:location completionHandler:^(<span class="hljs-built_in">NSArray</span> *placemarks, <span class="hljs-built_in">NSError</span> *error) {

        <span class="hljs-keyword">for</span> (CLPlacemark *placemark in placemarks) {
            <span class="hljs-built_in">NSLog</span>(@<span class="hljs-string">"%@ %@ %f %f"</span>, placemark<span class="hljs-variable">.name</span>, placemark<span class="hljs-variable">.addressDictionary</span>, placemark<span class="hljs-variable">.location</span><span class="hljs-variable">.coordinate</span><span class="hljs-variable">.latitude</span>, placemark<span class="hljs-variable">.location</span><span class="hljs-variable">.coordinate</span><span class="hljs-variable">.longitude</span>);
            <span class="hljs-keyword">self</span><span class="hljs-variable">.reverseDetailAddressLabel</span><span class="hljs-variable">.text</span> = placemark<span class="hljs-variable">.locality</span>;
        }
    }];
}

<span class="hljs-preprocessor">#pragma mark - 懒加载</span>
- (CLGeocoder *)geocoder
{
    <span class="hljs-keyword">if</span> (!_geocoder) {
        _geocoder = [[CLGeocoder alloc] init];
    }
    <span class="hljs-keyword">return</span> _geocoder;
}

<span class="hljs-keyword">@end</span></code>

四：知识扩充CLGeocoder

使用CLGeocoder可以完成“地理编码”和“反地理编码”

地理编码：根据给定的地名，获得具体的位置信息（比如经纬度、地址的全称等）

反地理编码：根据给定的经纬度，获得具体的位置信息

>地理编码方法

<code class="hljs erlang has-numbering"><span class="hljs-pp">- <span class="hljs-params">(void)</span>geocodeAddressString:<span class="hljs-params">(<span class="hljs-variable">NSString</span> *)</span>addressString completionHandler:<span class="hljs-params">(<span class="hljs-variable">CLGeocodeCompletionHandler</span>)</span>completionHandler;</span></code>

>反地理编码方法

<code class="hljs erlang has-numbering"><span class="hljs-pp">- <span class="hljs-params">(void)</span>reverseGeocodeLocation:<span class="hljs-params">(<span class="hljs-variable">CLLocation</span> *)</span>location completionHandler:<span class="hljs-params">(<span class="hljs-variable">CLGeocodeCompletionHandler</span>)</span>completionHandler;</span></code>

CLGeocodeCompletionHandler

当地理\反地理编码完成时，就会调用

<code class="hljs objectivec has-numbering">CLGeocodeCompletionHandler <span class="hljs-keyword">typedef</span> <span class="hljs-keyword">void</span> (^CLGeocodeCompletionHandler)(<span class="hljs-built_in">NSArray</span> *placemarks, <span class="hljs-built_in">NSError</span> *error);</code>

这个block传递2个参数

error ：当编码出错时（比如编码不出具体的信息）有值

placemarks ：里面装着CLPlacemark对象

CLPlacemark

CLPlacemark的字面意思是地标，封装详细的地址位置信息

地理位置

<code class="hljs objectivec has-numbering"><span class="hljs-keyword">@property</span> (<span class="hljs-keyword">nonatomic</span>, <span class="hljs-keyword">readonly</span>) CLLocation *location;</code>

区域

<code class="hljs objectivec has-numbering"><span class="hljs-keyword">@property</span> (<span class="hljs-keyword">nonatomic</span>, <span class="hljs-keyword">readonly</span>) CLRegion *region;</code>

详细的地址信息

<code class="hljs objectivec has-numbering"><span class="hljs-keyword">@property</span> (<span class="hljs-keyword">nonatomic</span>, <span class="hljs-keyword">readonly</span>) <span class="hljs-built_in">NSDictionary</span> *addressDictionary;</code>

地址名称

<code class="hljs objectivec has-numbering"><span class="hljs-keyword">@property</span> (<span class="hljs-keyword">nonatomic</span>, <span class="hljs-keyword">readonly</span>) <span class="hljs-built_in">NSString</span> *name;</code>

城市

<code class="hljs objectivec has-numbering"><span class="hljs-keyword">@property</span> (<span class="hljs-keyword">nonatomic</span>, <span class="hljs-keyword">readonly</span>) <span class="hljs-built_in">NSString</span> *locality;</code>

结构图