如何摆脱Android中的缓存位置

Posted 2023-04-14

【中文标题】如何摆脱Android中的缓存位置

【英文标题】：How to get rid of Cached Location in Android

【发布时间】：2015-03-04 22:44:41

【问题描述】：

正如您在 Google 的位置策略页面http://developer.android.com/guide/topics/location/strategies.html 中看到的那样，一旦读取位置，就会存储在缓存中（附上快速参考图片）

如您所见，位置已被缓存并因太旧而被关闭。我不想使用这个缓存。我怎样才能禁用它，以便每次 Google 收听并检索新鲜位置（我不关心电池只关心更准确的位置）

【参考方案1】：

将您之前的位置与 onLocationChanged() 方法中的新位置进行比较，如下所示：

Location prevLocation=null;
private static final int TWO_MINUTES = 1000 * 60 * 2; // time difference between location updates

// Define a listener that responds to location updates
LocationListener locationListener = new LocationListener() 

   //calls everytime when new location updates found
   public void onLocationChanged(Location location) 
     // Called when a new location is found by the network location provider.
      if(isBetterLocation(location, getPrevLocation()))

           // write your logic to use of new location

           // set your new location to prevlocation
           setPrevLocation(location);
      

   

   public void onStatusChanged(String provider, int status, Bundle extras) 

   public void onProviderEnabled(String provider) 

   public void onProviderDisabled(String provider) 
;

/** Determines whether one Location reading is better than the current Location fix
* @param location  The new Location that you want to evaluate
* @param currentBestLocation  The current Location fix, to which you want to compare the    new one
*/
 protected boolean isBetterLocation(Location location, Location currentBestLocation) 
 if (currentBestLocation == null) 
    // A new location is always better than no location
    return true;
 

// Check whether the new location fix is newer or older
long timeDelta = location.getTime() - currentBestLocation.getTime();
boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
boolean isNewer = timeDelta > 0;

// If it's been more than two minutes since the current location, use the new location
// because the user has likely moved
if (isSignificantlyNewer) 
    return true;
// If the new location is more than two minutes older, it must be worse
 else if (isSignificantlyOlder) 
    return false;


// Check whether the new location fix is more or less accurate
int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());
boolean isLessAccurate = accuracyDelta > 0;
boolean isMoreAccurate = accuracyDelta < 0;
boolean isSignificantlyLessAccurate = accuracyDelta > 200;

// Check if the old and new location are from the same provider
boolean isFromSameProvider = isSameProvider(location.getProvider(),
        currentBestLocation.getProvider());

// Determine location quality using a combination of timeliness and accuracy
if (isMoreAccurate) 
    return true;
 else if (isNewer && !isLessAccurate) 
    return true;
 else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) 
    return true;

return false;


/** Checks whether two providers are the same */
private boolean isSameProvider(String provider1, String provider2) 
 if (provider1 == null) 
   return provider2 == null;
 
 return provider1.equals(provider2);
 

public void setPrevLocation(Location prevLocation)
  this.prevLocation=prevLocation;

public Location getPrevLocation()
 return prevLocation;