【代碼】android通過criteria選擇合適的地理位置服務

LocationActivity.java

/*  LocationActivity.java
 *  @author octobershiner
 *  2011 7 24
 *  SE.HIT
 *  利用Criteria選擇最優的位置服務，演示定位用戶的位置並且監聽位置變化的代碼
 * */
package uni.location;

import android.app.Activity;
import android.content.Context;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.Vibrator;
import android.util.Log;
import android.widget.TextView;

public class LocationActivity extends Activity {
    /** Called when the activity is first created. */
    //創建lcoationManager對象
    private LocationManager manager;
    private static final String TAG = "LOCATION DEMO";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //獲取系統的服務，
        manager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
        //創建一個criteria對象
        Criteria criteria = new Criteria();   
        criteria.setAccuracy(Criteria.ACCURACY_COARSE);
        //設置不需要獲取海拔方向數據
        criteria.setAltitudeRequired(false);   
        criteria.setBearingRequired(false);
        //設置允許產生資費
        criteria.setCostAllowed(true);   
        //要求低耗電
        criteria.setPowerRequirement(Criteria.POWER_LOW);   
        String provider = manager.getBestProvider(criteria, false);   
        Log.i(TAG, "we choose "+ provider);
        Location location = manager.getLastKnownLocation(provider);
        //第一次獲得設備的位置
        updateLocation(location);   
        //重要函數，監聽數據測試
        manager.requestLocationUpdates(provider, 6000, 10,   
                       locationListener);   
                       
    }  
    
    //創建一個事件監聽器
   private final LocationListener locationListener = new LocationListener() {   
            public void onLocationChanged(Location location) {   
            updateLocation(location);   
            }   
            public void onProviderDisabled(String provider){
                updateLocation(null);   
                Log.i(TAG, "Provider now is disabled..");
            }   
            public void onProviderEnabled(String provider){
                Log.i(TAG, "Provider now is enabled..");
            }   
            public void onStatusChanged(String provider, int status,Bundle extras){ }   
    };   
    
//獲取用戶位置的函數，利用Log顯示
    private void updateLocation(Location location) {   
            String latLng;    
            if (location != null) {  
            double lat = location.getLatitude();   
            double lng = location.getLongitude();
            
            latLng = "Latitude:" + lat + "  Longitude:" + lng;   
            } else {   
            latLng = "Can't access your location";
            }
            Log.i(TAG, "The location has changed..");
            Log.i(TAG, "Your Location:" +latLng);
    }
    
}

同時修改manifest.xml文件

    <?xml version="1.0" encoding="utf-8"?>  
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"  
          package="uni.location"  
          android:versionCode="1"  
          android:versionName="1.0">  
        <uses-sdk android:minSdkVersion="8" />  
      
        <application android:icon="@drawable/icon" android:label="@string/app_name">  
            <activity android:name=".LocationActivity"  
                      android:label="@string/app_name">  
                <intent-filter>  
                    <action android:name="android.intent.action.MAIN" />  
                    <category android:name="android.intent.category.LAUNCHER" />  
                </intent-filter>  
            </activity>  
      
        </application>  
            <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />   
    </manifest>  

演示結果：

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網絡服務並沒有打開，但是選擇最佳provider的時候，參數選擇了false 所以同樣可以選擇。