我是一个新的android我想找出gps位置并定期将它们保存在sqlite数据库中。我希望在启用gps时它将位置发送到数据库，当禁用它时会显示设置的警告对话框。但在这种情况下，当我禁用gps它停止工作时它会给出一个致命的例外。任何帮助都将受到赞赏。
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;
boolean locarion =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;
NotificationManager nm;
Notification notification;
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;
// First get location from Network Provider
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;
}
/**
* 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/wifi enabled
* @return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch 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 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 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) {
Log.d("Provider Disable", "Provider Diasble");
showSettingsAlert();
}
@Override
public void onProviderEnabled(String provider) {
// Toast.makeText(this, "Provider Enabled ", Toast.LENGTH_SHORT).show();
Log.d("Provider Enable", "Provider Enable");
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
//Log.d("Status changed", "status changed");
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}
这是我的日志
12-09 01:01:10.188: E/AndroidRuntime(13936): FATAL EXCEPTION: main
12-09 01:01:10.188: E/AndroidRuntime(13936): android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@4053e520 is not valid; is your activity running?
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.view.ViewRoot.setView(ViewRoot.java:527)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.view.Window$LocalWindowManager.addView(Window.java:424)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.app.Dialog.show(Dialog.java:241)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.app.AlertDialog$Builder.show(AlertDialog.java:802)
12-09 01:01:10.188: E/AndroidRuntime(13936): at com.example.gps.GPSTracker.showSettingsAlert(GPSTracker.java:212)
12-09 01:01:10.188: E/AndroidRuntime(13936): at com.example.gps.GPSTracker.onProviderDisabled(GPSTracker.java:242)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.location.LocationManager$ListenerTransport._handleMessage(LocationManager.java:240)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.location.LocationManager$ListenerTransport.access$000(LocationManager.java:160)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.location.LocationManager$ListenerTransport$1.handleMessage(LocationManager.java:176)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.os.Handler.dispatchMessage(Handler.java:99)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.os.Looper.loop(Looper.java:123)
12-09 01:01:10.188: E/AndroidRuntime(13936): at android.app.ActivityThread.main(ActivityThread.java:3683)
12-09 01:01:10.188: E/AndroidRuntime(13936): at java.lang.reflect.Method.invokeNative(Native Method)
12-09 01:01:10.188: E/AndroidRuntime(13936): at java.lang.reflect.Method.invoke(Method.java:507)
12-09 01:01:10.188: E/AndroidRuntime(13936): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
12-09 01:01:10.188: E/AndroidRuntime(13936): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
12-09 01:01:10.188: E/AndroidRuntime(13936): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：0)
您正在尝试使用传递给GPS跟踪器的活动显示一个对话框窗口作为其上下文，但活动不再可用，因此您会收到错误消息，告知您上下文无效。
您可能希望启动一个活动，并将其设置为看起来像一个对话框。