我创建了一个带有逐步说明的小型应用程序，以获取当前位置的 GPS 坐标。
完整的示例源代码在 Android 中的 “获取当前位置坐标”，“城市名称” 中。
看看它怎么运作：
我们需要做的就是在清单文件中添加此权限：
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />并创建一个 LocationManager 实例，如下所示：
LocationManager locationManager = (LocationManager)
getSystemService(Context.LOCATION_SERVICE);检查是否启用了 GPS。
然后实现 LocationListener 并获取坐标：
LocationListener locationListener = new MyLocationListener();
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER, 5000, 10, locationListener);这是这样做的示例代码
/*---------- Listener class to get coordinates ------------- */
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location loc) {
editLocation.setText("");
pb.setVisibility(View.INVISIBLE);
Toast.makeText(
getBaseContext(),
"Location changed: Lat: " + loc.getLatitude() + " Lng: "
+ loc.getLongitude(), Toast.LENGTH_SHORT).show();
String longitude = "Longitude: " + loc.getLongitude();
Log.v(TAG, longitude);
String latitude = "Latitude: " + loc.getLatitude();
Log.v(TAG, latitude);
/*------- To get city name from coordinates -------- */
String cityName = null;
Geocoder gcd = new Geocoder(getBaseContext(), Locale.getDefault());
List<Address> addresses;
try {
addresses = gcd.getFromLocation(loc.getLatitude(),
loc.getLongitude(), 1);
if (addresses.size() > 0) {
System.out.println(addresses.get(0).getLocality());
cityName = addresses.get(0).getLocality();
}
}
catch (IOException e) {
e.printStackTrace();
}
String s = longitude + "\n" + latitude + "\n\nMy Current City is: "
+ cityName;
editLocation.setText(s);
}
@Override
public void onProviderDisabled(String provider) {}
@Override
public void onProviderEnabled(String provider) {}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {}
}这是其他答案的其他信息。
由于 Android 具有
GPS_PROVIDER and NETWORK_PROVIDER您可以同时注册两者并从两个onLocationChanged(Location location)到现在为止还挺好。现在的问题是我们需要两个结果还是我们应该取得最好的结果。据我所知， GPS_PROVIDER NETWORK_PROVIDER具有更好的准确性。
让我们定义Location字段：
private Location currentBestLocation = null;在开始侦听位置更改之前，我们将实现以下方法。此方法返回 GPS 与网络之间的最后一个已知位置。对于这种方法，最好是新的。
/**
* @return the last know best location
*/
private Location getLastBestLocation() {
Location locationGPS = mLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
Location locationNet = mLocationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
long GPSLocationTime = 0;
if (null != locationGPS) { GPSLocationTime = locationGPS.getTime(); }
long NetLocationTime = 0;
if (null != locationNet) {
NetLocationTime = locationNet.getTime();
}
if ( 0 < GPSLocationTime - NetLocationTime ) {
return locationGPS;
}
else {
return locationNet;
}
}每次检索新位置时，我们都会将其与以前的结果进行比较。
...
static final int TWO_MINUTES = 1000 * 60 * 2;
...onLocationChanged添加了一个新方法：
@Override
public void onLocationChanged(Location location) {
makeUseOfNewLocation(location);
if(currentBestLocation == null){
currentBestLocation = location;
}
....
}
/**
* This method modify the last know good location according to the arguments.
*
* @param location The possible new location.
*/
void makeUseOfNewLocation(Location location) {
if ( isBetterLocation(location, currentBestLocation) ) {
currentBestLocation = location;
}
}
....
/** 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);
}
....您可以通过GPS_PROVIDER or NETWORK_PROVIDER查找位置。
Android 中的位置服务概述。
这是一个尝试使用 GPS 查找位置的示例。如果您的 GPS 不可用，请尝试使用网络查找位置。
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) {
// No network provider is enabled
} 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 latitude/longitude 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;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app.
* */
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/Wi-Fi enabled
* @return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog.
* On pressing the Settings button it will launch Settings Options.
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing the Settings button.
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// On pressing the cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}活动 - AndroidGPSTrackingActivity.java
public class AndroidGPSTrackingActivity extends Activity {
Button btnShowLocation;
// GPSTracker class
GPSTracker gps;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnShowLocation = (Button) findViewById(R.id.btnShowLocation);
// Show location button click event
btnShowLocation.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// Create class object
gps = new GPSTracker(AndroidGPSTrackingActivity.this);
// Check if GPS enabled
if(gps.canGetLocation()) {
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
// \n is for new line
Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
} else {
// Can't get location.
// GPS or network is not enabled.
// Ask user to enable GPS/network in settings.
gps.showSettingsAlert();
}
}
});
}
}布局 - main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button android:id="@+id/btnShowLocation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Show Location"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"/>
</RelativeLayout>AndroidManifest.xml
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />