我正在尝试在应用启动时获取用户的地理位置，即在启动画面期间。
我的方法是在主要活动中使用asynctask从单独的类中获取Geo位置。我是android的新手，所以我可能会错过任何东西。以下是我为获取用户的地理位置而编写的示例代码：
SplashScreenActivity.java （在没有意向服务的情况下获取地理位置）
package work.office;
import work.office.GeoLocationFinder.LocationResult;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.Menu;
public class SplashScreenActivity extends Activity {
private static final String TAG = "SplashScreenActivity";
private ProgressDialog pd = null;
private Object data = null;
LocationResult locationResult;
Location newLocation = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash_screen);
new GetGeoLocationAsyncTask(getApplicationContext()).execute();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.splash_screen, menu);
return true;
}
private class GetGeoLocationAsyncTask extends
AsyncTask<Void, Integer, Location> {
private static final String TAG = "GetGeoLocationAsyncTask";
private Context ctx = null;
public GetGeoLocationAsyncTask(Context applicationContext) {
this.ctx = applicationContext;
}
@Override
protected void onPreExecute() {
pd = new ProgressDialog(SplashScreenActivity.this);
pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
pd.setTitle("Loading...");
pd.setMessage("Finding your geo location... Please wait");
pd.setCancelable(Boolean.FALSE);
pd.setIndeterminate(Boolean.TRUE);
pd.setMax(100);
pd.setProgress(0);
pd.show();
super.onPreExecute();
}
@Override
protected Location doInBackground(Void... params) {
LocationResult locationResult = new LocationResult() {
@Override
public void gotLocation(Location location) {
if (location != null) {
newLocation = new Location(location);
newLocation.set(location);
} else {
Log.d(TAG, "Location received is null");
}
}
};
GeoLocationFinder geoLocationFinder = new GeoLocationFinder();
geoLocationFinder.getLocation(this.ctx,
locationResult);
return newLocation;
}
@Override
protected void onPostExecute(Location result) {
super.onPostExecute(result);
if (result != null) {
Log.d(TAG,
"Got coordinates, congratulations. Longitude = "
+ result.getLongitude() + " Latitude = "
+ result.getLatitude());
} else {
Log.d(TAG, "Coordinates are null :(");
}
pd.dismiss();
}
}
}
GeoLocationFinder.java
package work.office;
import java.util.Timer;
import java.util.TimerTask;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.util.Log;
public class GeoLocationFinder {
private static final String TAG = "GeoLocationFinder";
Timer locationTimer;
LocationManager locationManager;
Location location;
private static final int min_update_time = 20000; // in msec
private static final int min_distance_for_update = 10; // in meters
LocationResult locationResult;
boolean gps_enabled = Boolean.FALSE;
boolean network_enabled = Boolean.FALSE;
public boolean getLocation(Context ctx, LocationResult result) {
locationResult = result;
if (locationManager == null) {
locationManager = (LocationManager) ctx
.getSystemService(Context.LOCATION_SERVICE);
}
try {
gps_enabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
} catch (Exception e) {
Log.d(TAG, "GPS enabled exception: " + e.getMessage());
}
try {
network_enabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
} catch (Exception e) {
Log.d(TAG, "Network enabled exception: " + e.getMessage());
}
if (!gps_enabled && !network_enabled) {
Log.d(TAG, "You are doomed boy!!");
return Boolean.FALSE;
}
if (gps_enabled) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER, min_update_time,
min_distance_for_update, locationListenerGps);
}
if (network_enabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER, min_update_time,
min_distance_for_update, locationListenerNetwork);
}
locationTimer = new Timer();
locationTimer.schedule(new GetLastLocation(), 20000);
return Boolean.TRUE;
}
LocationListener locationListenerGps = new LocationListener() {
public void onLocationChanged(Location location) {
locationTimer.cancel();
locationResult.gotLocation(location);
locationManager.removeUpdates(this);
locationManager.removeUpdates(locationListenerGps);
}
@Override
public void onProviderDisabled(String provider) {
Log.d(TAG, "GPS provider disabled" + provider);
}
@Override
public void onProviderEnabled(String provider) {
Log.d(TAG, "GPS provider enabled" + provider);
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
Log.d(TAG, "GPS status changed");
}
};
LocationListener locationListenerNetwork = new LocationListener() {
public void onLocationChanged(Location location) {
locationTimer.cancel();
locationResult.gotLocation(location);
locationManager.removeUpdates(this);
locationManager.removeUpdates(locationListenerNetwork);
}
@Override
public void onProviderDisabled(String provider) {
Log.d(TAG, "Network provider disabled. " + provider);
}
@Override
public void onProviderEnabled(String provider) {
Log.d(TAG, "Network provider enabled. " + provider);
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
Log.d(TAG, "Network status changed.");
}
};
private class GetLastLocation extends TimerTask {
@Override
public void run() {
locationManager.removeUpdates(locationListenerGps);
locationManager.removeUpdates(locationListenerNetwork);
Location net_loc = null, gps_loc = null;
if (gps_enabled) {
gps_loc = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
}
if (network_enabled) {
net_loc = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
}
if (gps_loc != null && net_loc != null) {
if (gps_loc.getTime() > net_loc.getTime()) {
locationResult.gotLocation(gps_loc);
} else {
locationResult.gotLocation(net_loc);
}
return;
}
if (gps_loc != null) {
locationResult.gotLocation(gps_loc);
return;
}
if (net_loc != null) {
locationResult.gotLocation(net_loc);
return;
}
locationResult.gotLocation(null);
}
}
public static abstract class LocationResult {
public abstract void gotLocation(Location location);
}
}
当我在手机上安装这个apk时，我收到此错误：引起：java.lang.RuntimeException：无法在未调用Looper.prepare（）的线程内创建处理程序（在后台的SplashScreenActivity.java中）线程我试图获取位置）
This question也提到错误但在我的上下文中我无法链接它。可能是因为我在后台线程中使用了SplashScreenActivity上下文。但如何纠正呢？另外，在启动画面期间找到地理位置的最佳方法是什么？请帮忙。
答案 0 :(得分：2)
你严重过度了。在这种情况下，AsyncTask没有完成任何事情。这是简化但仍然异步获取位置的代码：
package work.office;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.Menu;
public class SplashScreenActivity extends Activity {
private static final String TAG = "SplashScreenActivity";
private ProgressDialog pd = null;
private Object data = null;
GeoLocationFinder.LocationResult locationResult;
Location newLocation = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash_screen);
setupLocation();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.splash_screen, menu);
return true;
}
private void setupLocation() {
pd = new ProgressDialog(SplashScreenActivity.this);
pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
pd.setTitle("Loading...");
pd.setMessage("Finding your geo location... Please wait");
pd.setCancelable(Boolean.FALSE);
pd.setIndeterminate(Boolean.TRUE);
pd.setMax(100);
pd.setProgress(0);
pd.show();
GeoLocationFinder.LocationResult locationResult = new GeoLocationFinder.LocationResult() {
@Override
public void gotLocation(Location location) {
if (location != null) {
newLocation = new Location(location);
newLocation.set(location);
Log.d(TAG,
"Got coordinates, congratulations. Longitude = "
+ newLocation.getLongitude() + " Latitude = "
+ newLocation.getLatitude());
pd.dismiss();
} else {
Log.d(TAG, "Location received is null");
}
}
};
GeoLocationFinder geoLocationFinder = new GeoLocationFinder();
geoLocationFinder.getLocation(this,
locationResult);
}
}