我正试图找到解决这个问题的好办法。我制作了我的应用程序以便找到我的位置。它似乎过于复杂但很容易。但是，在谷歌推荐之后，我现在尝试将此代码作为异步任务运行，因此它不会占用UI。但是我甚至无法弄清楚如何让编译代码从不介意实际运行。错误是当我引用它以删除侦听器时无法解析locationManager。我已尝试使用此处Android find GPS location once, show loading dialog上发布的代码。但是在这个例子中，currentLocation似乎没有引用任何东西，我遇到了试图对其进行排序的问题。我浪费了将近一整天的时间试图解决这个问题，所以如果有人能指出我正确的方向，我真的很感激。
private class LocationControl extends AsyncTask<Context, Void, Location> {
public Location alocation;
private LocatoinManager locationManager;
@Override
public Location doInBackground(Context... params) {
locationManager = (LocationManager) params[0].getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(locationManager.GPS_PROVIDER, 0, 0, locationListener);
return alocation;
}
public LocationListener locationListener = new LocationListener() {
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
public void onLocationChanged(android.location.Location mlocation) {
saveLocation(mlocation);
locationManager.removeUpdates(locationListener);
}
};
void saveLocation(android.location.Location location){
alocation = location;
}
@Override
protected void onPostExecute(Location result) {
useLocation(result);
super.onPostExecute(result);
}
@Override
protected void onPreExecute() {
dialog.show(WasserSportLotse.this, " ", "Finding location...");
super.onPreExecute();
}
}
所以我用你的建议更改了代码，现在编译了。我已在此处更新代码以表示我正在运行的内容。我在locationManager requestsLocationUpdates时收到运行时错误。这是logCat。任何想法？
04-15 14:57:56.742: ERROR/AndroidRuntime(18328): Uncaught handler: thread AsyncTask #1 exiting due to uncaught exception
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): java.lang.RuntimeException: An error occured while executing doInBackground()
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at android.os.AsyncTask$3.done(AsyncTask.java:200)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:234)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:258)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at java.util.concurrent.FutureTask.run(FutureTask.java:122)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:648)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:673)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at java.lang.Thread.run(Thread.java:1060)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at android.os.Handler.<init>(Handler.java:121)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at android.location.LocationManager$ListenerTransport$1.<init>(LocationManager.java:128)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at android.location.LocationManager$ListenerTransport.<init>(LocationManager.java:126)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at android.location.LocationManager._requestLocationUpdates(LocationManager.java:697)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at android.location.LocationManager.requestLocationUpdates(LocationManager.java:619)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at com.WasserSportLotse.WasserSportLotse$LocationControl.doInBackground(WasserSportLotse.java:62)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at com.WasserSportLotse.WasserSportLotse$LocationControl.doInBackground(WasserSportLotse.java:1)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at android.os.AsyncTask$2.call(AsyncTask.java:185)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:256)
04-15 14:57:56.942: ERROR/AndroidRuntime(18328): ... 4 more
04-15 14:58:23.451: ERROR/AndroidRuntime(18356): Uncaught handler: thread AsyncTask #1 exiting due to uncaught exception
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): java.lang.RuntimeException: An error occured while executing doInBackground()
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at android.os.AsyncTask$3.done(AsyncTask.java:200)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:234)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:258)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at java.util.concurrent.FutureTask.run(FutureTask.java:122)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:648)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:673)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at java.lang.Thread.run(Thread.java:1060)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at android.os.Handler.<init>(Handler.java:121)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at android.location.LocationManager$ListenerTransport$1.<init>(LocationManager.java:128)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at android.location.LocationManager$ListenerTransport.<init>(LocationManager.java:126)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at android.location.LocationManager._requestLocationUpdates(LocationManager.java:697)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at android.location.LocationManager.requestLocationUpdates(LocationManager.java:619)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at com.WasserSportLotse.WasserSportLotse$LocationControl.doInBackground(WasserSportLotse.java:62)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at com.WasserSportLotse.WasserSportLotse$LocationControl.doInBackground(WasserSportLotse.java:1)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at android.os.AsyncTask$2.call(AsyncTask.java:185)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:256)
04-15 14:58:23.642: ERROR/AndroidRuntime(18356): ... 4 more
答案 0 :(得分：27)
public class FastMainActivity extends Activity {
Button searchBtn = null;
Intent locatorService = null;
AlertDialog alertDialog = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
searchBtn = (Button) findViewById(R.id.searchBtn);
searchBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (!startService()) {
CreateAlert("Error!", "Service Cannot be started");
} else {
Toast.makeText(FastMainActivity.this, "Service Started",
Toast.LENGTH_LONG).show();
}
}
});
}
public boolean stopService() {
if (this.locatorService != null) {
this.locatorService = null;
}
return true;
}
public boolean startService() {
try {
// this.locatorService= new
// Intent(FastMainActivity.this,LocatorService.class);
// startService(this.locatorService);
FetchCordinates fetchCordinates = new FetchCordinates();
fetchCordinates.execute();
return true;
} catch (Exception error) {
return false;
}
}
public AlertDialog CreateAlert(String title, String message) {
AlertDialog alert = new AlertDialog.Builder(this).create();
alert.setTitle(title);
alert.setMessage(message);
return alert;
}
public class FetchCordinates extends AsyncTask<String, Integer, String> {
ProgressDialog progDailog = null;
public double lati = 0.0;
public double longi = 0.0;
public LocationManager mLocationManager;
public VeggsterLocationListener mVeggsterLocationListener;
@Override
protected void onPreExecute() {
mVeggsterLocationListener = new VeggsterLocationListener();
mLocationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mLocationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER, 0, 0,
mVeggsterLocationListener);
progDailog = new ProgressDialog(FastMainActivity.this);
progDailog.setOnCancelListener(new OnCancelListener() {
@Override
public void onCancel(DialogInterface dialog) {
FetchCordinates.this.cancel(true);
}
});
progDailog.setMessage("Loading...");
progDailog.setIndeterminate(true);
progDailog.setCancelable(true);
progDailog.show();
}
@Override
protected void onCancelled(){
System.out.println("Cancelled by user!");
progDialog.dismiss();
mLocationManager.removeUpdates(mVeggsterLocationListener);
}
@Override
protected void onPostExecute(String result) {
progDailog.dismiss();
Toast.makeText(FastMainActivity.this,
"LATITUDE :" + lati + " LONGITUDE :" + longi,
Toast.LENGTH_LONG).show();
}
@Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
while (this.lati == 0.0) {
}
return null;
}
public class VeggsterLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location location) {
int lat = (int) location.getLatitude(); // * 1E6);
int log = (int) location.getLongitude(); // * 1E6);
int acc = (int) (location.getAccuracy());
String info = location.getProvider();
try {
// LocatorService.myLatitude=location.getLatitude();
// LocatorService.myLongitude=location.getLongitude();
lati = location.getLatitude();
longi = location.getLongitude();
} catch (Exception e) {
// progDailog.dismiss();
// Toast.makeText(getApplicationContext(),"Unable to get Location"
// , Toast.LENGTH_LONG).show();
}
}
@Override
public void onProviderDisabled(String provider) {
Log.i("OnProviderDisabled", "OnProviderDisabled");
}
@Override
public void onProviderEnabled(String provider) {
Log.i("onProviderEnabled", "onProviderEnabled");
}
@Override
public void onStatusChanged(String provider, int status,
Bundle extras) {
Log.i("onStatusChanged", "onStatusChanged");
}
}
}
}
答案 1 :(得分：4)
在致电Looper.prepare()之前添加locationManager.requestLocationUpdates(locationManager.GPS_PROVIDER, 0, 0, locationListener);
记得在之后调用Looper.loop（）。
答案 2 :(得分：1)
首先修复你的编译问题， 移动
LocationManager locationManager = (LocationManager)params[0].getSystemService(Context.LOCATION_SERVICE);
因此它是该类的私有成员变量。
LocationManager不必位于AsyncTask中。它不会占用UI，所有更新都已异步。这只会给您的项目增加不必要的复杂功能。
您可能只需要将useLocation移动到onLockationChanged。
答案 3 :(得分：0)
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
Log.w("DOCOMO-2","Network Connection failed");
}
else
{
this.canGetLocation = true;
// First get location from Network Provider
if (isNetworkEnabled)
{
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
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);
if (locationManager != null)
{
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null)
{
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
locationManager=null;
location=null;
}
catch (Exception e)
{
locationManager=null;
location=null;
e.printStackTrace();
}
return location;
}