Android: How to get location information from inte

问题:

I am trying to use Android's LocationManager requestLocationUpdates. Everything is working until I try to extract the actual location object that in my broadcast receiver. Do I need to specifically define the "extras" to my custom intent so that the Android LocationManager before I pass it to requestLocationUpdates so it knows how to add it into the intent, or will it create the extras-bundle regardless when it passes the fired intent to the broadcast receiver?

My code looks like this:

Intent intent = new Intent("com.myapp.swarm.LOCATION_READY");
PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(),
    0, intent, 0);

//Register for broadcast intents
int minTime = 5000;
int minDistance = 0;
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, minTime,
    minDistance, pendingIntent);

I have a broadcast receiver that is defined in the manifesto as:

<receiver android:name=".LocationReceiver">
    <intent-filter>
        <action android:name="com.myapp.swarm.LOCATION_READY" />
        <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>
</receiver>

And the broadcast receiver class as:

public class LocationReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
    //Do this when the system sends the intent
    Bundle b = intent.getExtras();
    Location loc = (Location)b.get("KEY_LOCATION_CHANGED");

    Toast.makeText(context, loc.toString(), Toast.LENGTH_SHORT).show(); 
    }
}

My "loc" object is coming up null.

回答1:

OK, I managed to fix it by changing the KEY_LOCATION_CHANGED in the broadcast receiver code to:

public class LocationReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
    //Do this when the system sends the intent
    Bundle b = intent.getExtras();
    Location loc = (Location)b.get(android.location.LocationManager.KEY_LOCATION_CHANGED);

    Toast.makeText(context, loc.toString(), Toast.LENGTH_SHORT).show(); 
    }
}

回答2:

i ve tried to code and test the solution you proposed, since i am facing similar problems concerning proximity alerts and intents carrying location objects. According the information you provided, you managed to overcome the null object retrieval, on the BroadcastReceiver's side. What you might did not observe is that now you should be receiving the same location as the one your intent was first created (also seen it as: intent caching problem).

In order to overcome this problem, i used FLAG_CANCEL_CURRENT, as being proposed by many people here and it works pretty fine, fetching fresh (and juicy :P) location values. So the line defining your pending intent should look like this:

PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(),
    0, intent, PendingIntent.FLAG_CANCEL_CURRENT);

However, you can ignore this if:

• your purpose was just to receive a location value once
• you managed to overcome it in some other way not visible in your post