如何解决如何使用AsyncTask获取位置
| 我正在努力寻找解决这个问题的好方法。我做了我的应用程序，以便它找到我的位置。似乎过于复杂，但也很容易。但是，按照谷歌的建议，我现在试图将此代码作为Async任务运行，以免与UI发生冲突。但是，我什至无法弄清楚如何使代码进行编译，不要介意实际运行。错误是我引用引用它来删除侦听器时无法解析locationManager。我尝试使用发布在此处的代码一次找到Android GPS位置，显示加载对话框。但是，在此示例中，currentLocation似乎未引用任何内容，因此在尝试进行排序时遇到了问题。我浪费了整整一天的时间来尝试解决此问题，因此，如果有人能指出正确的方向，我将不胜感激。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,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();
}
}
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
解决方法
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,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\");
}
}
}
}
locationManager.requestLocationUpdates(locationManager.GPS_PROVIDER,locationListener);
Looper.prepare()
LocationManager locationManager = (LocationManager)params[0].getSystemService(Context.LOCATION_SERVICE);
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,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;
}
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