安卓应用无法获取位置求助：需等待一天才能获取当前/已知位置（附代码）

Hey Edson, let's break down why your app is taking a full day to get location data and fix it right away—your code has a few critical bugs that are blocking location updates, plus some easy tweaks to make it more reliable.

First, Let's Spot the Critical Bugs in Your Current Code #

• Reversed Permission Check in onLocationChanged: This is the biggest problem! You wrote:

  if (PermissionsUtils.hasPermissions(this, locationPermissions)) {
      return;
  }
  

  This means if the user has granted permissions, you immediately exit the method without processing the location data. That's why you never get any location updates at all!
• No Fallback for Empty getLastKnownLocation: If there's no saved location, you request updates but don't handle cases where the device can't get a fix quickly.
• Overly Aggressive Update Parameters: requestLocationUpdates(provider, 1000, 0, this) asks for updates every 1 second and every 0 meters—this is too frequent, drains battery, and might cause the system to throttle your requests.

Fixed Version of Your Code #

Let's rewrite the location logic with these fixes, plus add proper permission handling:

// MARK: - GET CURRENT LOCATION ------------------------------------------------------
protected void getCurrentLocation() {
    // First, check if permissions are granted—if not, request them
    if (!PermissionsUtils.hasPermissions(this, locationPermissions)) {
        ActivityCompat.requestPermissions(this, locationPermissions, 1001);
        return;
    }

    Criteria criteria = new Criteria();
    criteria.setAccuracy(Criteria.ACCURACY_COARSE); // Use coarse for faster fixes, switch to fine if needed
    criteria.setPowerRequirement(Criteria.POWER_LOW);
    criteria.setAltitudeRequired(false);
    criteria.setBearingRequired(false);

    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    assert locationManager != null;
    String provider = locationManager.getBestProvider(criteria, true);

    // Try last known location first
    currentLocation = locationManager.getLastKnownLocation(provider);
    if (currentLocation != null) {
        getCityCountryNames();
        queryAds(); // Don't forget to trigger your ad query here
    } else {
        // Request a single location update (not continuous) with a timeout
        locationManager.requestSingleUpdate(provider, this, Looper.getMainLooper());
        
        // Add a timeout in case location takes too long
        new Handler(Looper.getMainLooper()).postDelayed(() -> {
            if (currentLocation == null) {
                // Fallback to default location if no fix after 10 seconds
                Configs.simpleAlert(getString(R.string.get_location_failure), AdsListActivity.this);
                currentLocation = new Location("provider");
                currentLocation.setLatitude(Configs.DEFAULT_LOCATION.latitude);
                currentLocation.setLongitude(Configs.DEFAULT_LOCATION.longitude);
                cityCountryTV.setText(getString(R.string.not_available_text_placeholder));
                queryAds();
            }
        }, 10000); // 10-second timeout
    }
}

@Override
public void onLocationChanged(Location location) {
    // Now, only return if permissions are NOT granted
    if (!PermissionsUtils.hasPermissions(this, locationPermissions)) {
        return;
    }

    // Stop listening for updates since we only need one fix
    if (locationManager != null) {
        locationManager.removeUpdates(this);
    }

    currentLocation = location;
    if (currentLocation != null) {
        getCityCountryNames();
        queryAds(); // Trigger your ad query once location is found
    } else {
        // Fallback to default
        Configs.simpleAlert(getString(R.string.get_location_failure), AdsListActivity.this);
        currentLocation = new Location("provider");
        currentLocation.setLatitude(Configs.DEFAULT_LOCATION.latitude);
        currentLocation.setLongitude(Configs.DEFAULT_LOCATION.longitude);
        cityCountryTV.setText(getString(R.string.not_available_text_placeholder));
        queryAds();
    }
}

// Handle permission request result
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == 1001) {
        if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            // Permissions granted—try getting location again
            getCurrentLocation();
        } else {
            // User denied permissions—use default location
            Configs.simpleAlert("Location permissions are required to show local ads", AdsListActivity.this);
            currentLocation = new Location("provider");
            currentLocation.setLatitude(Configs.DEFAULT_LOCATION.latitude);
            currentLocation.setLongitude(Configs.DEFAULT_LOCATION.longitude);
            cityCountryTV.setText(getString(R.string.not_available_text_placeholder));
            queryAds();
        }
    }
}

Key Improvements Made #

1. Fixed the Permission Check: Now onLocationChanged only exits if permissions are missing, so valid location data gets processed.
2. Added Permission Request Flow: If the user hasn't granted permissions, the app asks for them and retries location fetching once granted.
3. Single Location Update: Used requestSingleUpdate instead of continuous updates—we only need one location fix, not ongoing tracking.
4. Timeout Fallback: If no location is found after 10 seconds, the app switches to your default location immediately instead of waiting indefinitely.
5. Triggered queryAds(): Ensured your ad query runs as soon as a valid location (or default) is set.

Bonus: Use Fused Location Provider (More Reliable for Modern Android) #

The old LocationManager works but is less reliable on Android 10+. For better results, use Google's Fused Location Provider. Here's a quick snippet to get you started:

First, add this to your app-level build.gradle dependencies:

implementation 'com.google.android.gms:play-services-location:21.0.1'

Then update your location logic:

private FusedLocationProviderClient fusedLocationClient;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // ... your existing onCreate code
    fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
}

protected void getCurrentLocation() {
    if (!PermissionsUtils.hasPermissions(this, locationPermissions)) {
        ActivityCompat.requestPermissions(this, locationPermissions, 1001);
        return;
    }

    // Get last known location first
    fusedLocationClient.getLastKnownLocation()
            .addOnSuccessListener(this, location -> {
                if (location != null) {
                    currentLocation = location;
                    getCityCountryNames();
                    queryAds();
                } else {
                    // Request a single high-priority location update
                    LocationRequest locationRequest = LocationRequest.create();
                    locationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
                    locationRequest.setNumUpdates(1);
                    locationRequest.setInterval(0);
                    locationRequest.setFastestInterval(0);

                    fusedLocationClient.requestLocationUpdates(locationRequest, locationCallback, Looper.getMainLooper());

                    // Timeout fallback
                    new Handler(Looper.getMainLooper()).postDelayed(() -> {
                        if (currentLocation == null) {
                            Configs.simpleAlert(getString(R.string.get_location_failure), AdsListActivity.this);
                            // Set default location
                            currentLocation = new Location("provider");
                            currentLocation.setLatitude(Configs.DEFAULT_LOCATION.latitude);
                            currentLocation.setLongitude(Configs.DEFAULT_LOCATION.longitude);
                            cityCountryTV.setText(getString(R.string.not_available_text_placeholder));
                            queryAds();
                        }
                    }, 10000);
                }
            });
}

private final LocationCallback locationCallback = new LocationCallback() {
    @Override
    public void onLocationResult(LocationResult locationResult) {
        super.onLocationResult(locationResult);
        if (locationResult == null) {
            return;
        }
        for (Location location : locationResult.getLocations()) {
            if (location != null) {
                currentLocation = location;
                getCityCountryNames();
                queryAds();
                fusedLocationClient.removeLocationUpdates(this);
            }
        }
    }
};

Final Notes #

• Add Permissions to AndroidManifest.xml: Make sure you have these lines:

  <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
  <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
  <uses-feature android:name="android.hardware.location.gps" android:required="false" />
  

• Test with Location Enabled: Ensure the device's location services are turned on (GPS or Wi-Fi-based location).

内容的提问来源于stack exchange，提问作者Edson Francis