我的 Android 应用程序使用手机网络或 GPS 获取离用户最近的五个街道地址,具体取决于启用了哪一个。
问题是我请求五个位置,但收到一个精确位置,然后是大约 3 个糟糕的位置,然后 1 个没有得到位置。
假设我住在123 Wilbur Rd., Townsville
, 我的结果将是
1. 143 Wilbur Rd., Townsville
2. USA, null
3. null, Townsville
4. null, NearbyVillage
5. null, null
有什么方法可以提高这些结果的质量,还是应该自动选择第一个?我的定位器类的相关方法如下
GPSTracker.java
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
Log.d("TAG", "No GPS or Network enabled. Unable to get location.");
Toast.makeText(mContext, "Error: No GPS or Network available.", Toast.LENGTH_LONG).show();
} else {
this.canGetLocation = true;
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Attempts to get the closest five address using getLatitiudeAndLongitude()
* Returns the closest address if an address is found, otherwise returns dummy values
* @return an array of the nearest five addresses in a String array
*/
public String[] getNearestFiveAddresses(){
String[] result = {"fail", "fail", "fail", "fail", "fail"};//TODO dummy values for now
int RESULT_SIZE = 5;
//try to get closest address
try {
Geocoder geo = new Geocoder(mContext, Locale.getDefault());
List<Address> addresses = geo.getFromLocation(latitude, longitude, 5);
if (addresses.isEmpty()) {
Log.d("TAG", "No addresses found");
}
else {
if (addresses.size() > 0) {
for(int i=0; i<RESULT_SIZE; i++){
result[i] = addresses.get(i).getAddressLine(i) + ", " + addresses.get(i).getLocality();
}
}
}
}
catch (Exception e) {
e.printStackTrace(); // getFromLocation() may sometimes fail
}
return result;
}
...
}