Android(安卓)GPS基础

package org.example.locationtest;import java.util.List;import android.app.Activity;import android.location.Criteria;import android.location.Location;import android.location.LocationListener;import android.location.LocationManager;import android.location.LocationProvider;import android.os.Bundle;import android.widget.TextView;public class LocationTest extends Activity implements      LocationListener {    // Define human readable names   private static final String[] A = { "invalid", "n/a", "fine", "coarse" };   private static final String[] P = { "invalid", "n/a", "low", "medium",         "high" };   private static final String[] S = { "out of service", "temporarily unavailable", "available" };      private LocationManager mgr;   private TextView output;   private String best;   @Override   public void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.main);      mgr = (LocationManager) getSystemService(LOCATION_SERVICE);       output = (TextView) findViewById(R.id.output);      log("Location providers:");      dumpProviders();       Criteria criteria = new Criteria();       best = mgr.getBestProvider(criteria, true);//获取最好的提供者      log("\nBest provider is: " + best);//      注：这里取到的GPS值是目前存储在GPS上的Location值，//      如果刚刚打开GPS就用这个方法取Location取到的会是上一次代开GPS时取到的旧值。//      等待GPS取得新值需要用LocationListener里的 onLocationChanged。      log("\nLocations (starting with last known):");      Location location = mgr.getLastKnownLocation(best); //通过最好的提供者获得GPS的方法      dumpLocation(location);   }      @Override   protected void onResume() {      super.onResume();      // Start updates (doc recommends delay >= 60000 ms)      mgr.requestLocationUpdates(best, 15000, 1, this);//通过best启动（例如设置成LocationManager.GPS_PROVIDER就是通过gps启动），Location更新的设置是每隔15000ms更新一次，最后一个参数是LocationListener的一个引用，这个类需要实现   }   @Override   protected void onPause() {      super.onPause();//      停止GPS运行：      mgr.removeUpdates(this);   }   //如果需要去到GPS启动后取到的Location,必须用这个！     public void onLocationChanged(Location location) {      dumpLocation(location);   }   // Provider被disable时触发此函数，比如GPS被关闭      public void onProviderDisabled(String provider) {      log("\nProvider disabled: " + provider);   }   //  Provider被enable时触发此函数，比如GPS被打开      public void onProviderEnabled(String provider) {      log("\nProvider enabled: " + provider);   }   // Provider的转态在可用、暂时不可用和无服务三个状态直接切换时触发此函数      public void onStatusChanged(String provider, int status,         Bundle extras) {      log("\nProvider status changed: " + provider + ", status="            + S[status] + ", extras=" + extras);   }   /** Write a string to the output window */   private void log(String string) {      output.append(string + "\n");   }   /** Write information from all location providers */   private void dumpProviders() {      List<String> providers = mgr.getAllProviders();      for (String provider : providers) {         dumpProvider(provider);      }   }   /** Write information from a single location provider */   private void dumpProvider(String provider) {      LocationProvider info = mgr.getProvider(provider);      StringBuilder builder = new StringBuilder();      builder.append("LocationProvider[")            .append("name=")            .append(info.getName())            .append(",enabled=")            .append(mgr.isProviderEnabled(provider))//检测GPS是否已经启动:            .append(",getAccuracy=")            .append(A[info.getAccuracy() + 1])            .append(",getPowerRequirement=")            .append(P[info.getPowerRequirement() + 1])            .append(",hasMonetaryCost=")            .append(info.hasMonetaryCost())            .append(",requiresCell=")            .append(info.requiresCell())            .append(",requiresNetwork=")            .append(info.requiresNetwork())            .append(",requiresSatellite=")            .append(info.requiresSatellite())            .append(",supportsAltitude=")            .append(info.supportsAltitude())            .append(",supportsBearing=")            .append(info.supportsBearing())            .append(",supportsSpeed=")            .append(info.supportsSpeed())            .append("]");      log(builder.toString());   }   /** Describe the given location, which might be null */   private void dumpLocation(Location location) {      if (location == null)         log("\nLocation[unknown]");      else//      double latitude = location.getLatitude();     //经度   //        double longitude = location.getLongitude(); //纬度   //        double altitude =  location.getAltitude();     //海拔            log("\n" + location.toString());   }}
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