【Based Android】android通過criteria選擇合適的地理位置服務

 1 /*  LocationActivity.java
 2  *  @author octobershiner
 3  *  2011 7 24
 4  *  SE.HIT
 5  *  利用Criteria選擇最優的位置服務，示範定位使用者的位置並且監聽位置變化的代碼
 6  * */
 7 package uni.location;
 8 
 9 import android.app.Activity;
10 import android.content.Context;
11 import android.location.Criteria;
12 import android.location.Location;
13 import android.location.LocationListener;
14 import android.location.LocationManager;
15 import android.os.Bundle;
16 import android.os.Vibrator;
17 import android.util.Log;
18 import android.widget.TextView;
19 
20 public class LocationActivity extends Activity {
21     /** Called when the activity is first created. */
22     //建立lcoationManager對象
23     private LocationManager manager;
24     private static final String TAG = "LOCATION DEMO";
25     @Override
26     public void onCreate(Bundle savedInstanceState) {
27         super.onCreate(savedInstanceState);
28         setContentView(R.layout.main);
29         //擷取系統的服務，
30         manager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
31         //建立一個criteria對象
32         Criteria criteria = new Criteria();   
33         criteria.setAccuracy(Criteria.ACCURACY_COARSE);
34         //設定不需要擷取海拔方向資料
35         criteria.setAltitudeRequired(false);   
36         criteria.setBearingRequired(false);
37         //設定允許產生資費
38         criteria.setCostAllowed(true);   
39         //要求低耗電
40         criteria.setPowerRequirement(Criteria.POWER_LOW);   
41         String provider = manager.getBestProvider(criteria, false);   
42         Log.i(TAG, "we choose "+ provider);
43         Location location = manager.getLastKnownLocation(provider);
44         //第一次獲得裝置的位置
45         updateLocation(location);   
46         //重要函數，監聽資料測試
47         manager.requestLocationUpdates(provider, 6000, 10,   
48                        locationListener);   
49                        
50     }  
51     
52     //建立一個事件監聽器
53    private final LocationListener locationListener = new LocationListener() {   
54             public void onLocationChanged(Location location) {   
55             updateLocation(location);   
56             }   
57             public void onProviderDisabled(String provider){
58                 updateLocation(null);   
59                 Log.i(TAG, "Provider now is disabled..");
60             }   
61             public void onProviderEnabled(String provider){
62                 Log.i(TAG, "Provider now is enabled..");
63             }   
64             public void onStatusChanged(String provider, int status,Bundle extras){ }   
65     };   
66     
67 //擷取使用者位置的函數，利用Log顯示
68     private void updateLocation(Location location) {   
69             String latLng;    
70             if (location != null) {  
71             double lat = location.getLatitude();   
72             double lng = location.getLongitude();
73             
74             latLng = "Latitude:" + lat + "  Longitude:" + lng;   
75             } else {   
76             latLng = "Can't access your location";
77             }
78             Log.i(TAG, "The location has changed..");
79             Log.i(TAG, "Your Location:" +latLng);
80     }
81     
82 }

同時修改manifest.xml檔案

 1 <?xml version="1.0" encoding="utf-8"?>    
 2 <manifest xmlns:android="http://schemas.android.com/apk/res/android"    
 3       package="uni.location"    
 4       android:versionCode="1"    
 5       android:versionName="1.0">    
 6     <uses-sdk android:minSdkVersion="8" />    
 7     
 8     <application android:icon="@drawable/icon" android:label="@string/app_name">    
 9         <activity android:name=".LocationActivity"    
10                   android:label="@string/app_name">    
11             <intent-filter>    
12                 <action android:name="android.intent.action.MAIN" />    
13                 <category android:name="android.intent.category.LAUNCHER" />    
14             </intent-filter>    
15         </activity>    
16     
17     </application>    
18         <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />     
19 </manifest>    

示範結果：

可任看到 我們只要求低的精確度並且最低電量，從最後一行可以看到我的虛擬機器網路服務並沒有開啟，但是選擇最佳provider的時候，參數選擇了false 所以同樣可以選擇。