为什么我对Facebook Graph API的调用没有显示任何内容？

Question

Ok, so I'm editing this to include the whole class with some new code I added over the past couple of hours. Basically, I'm looking to populate a Google Map with markers that represent a Facebook user's checkins. Unfortunately, my code has not been cooperating - I've tried reviewing the documentation that Facebook provides and searching the web for answers without coming up with anything useful. So far all I've been able to get the app to do is validate the app's permissions with Facebook and display the map, though I had tested the ability to add markers with dummy values in an earlier version of the app and that worked fine.

My earlier question dealt with why my calls to the Graph API weren't displaying anything - I had made the same call as listed in the AuthorizeListener sub-class, but was merely attempting to output the raw JSON string in a log entry instead of manipulating it. I think that whatever was the cause of that problem is probably the same cause of my current problem.

Anyway, how do I get my app to display markers for locations a user has checked in to? I think my code gets me off to a pretty good start, but there are obviously issues in my AuthorizeListener sub-class. What do you guys think?

public class FBCTActivity extends MapActivity {
public static Context mContext;
List<Overlay> mapOverlays;
FBCTMarkerOverlay markerLayer;
ArrayList<OverlayItem> overlays = new ArrayList<OverlayItem>();

// Facebook Application ID
private static final String APP_ID = "";

Facebook mFacebook = new Facebook(APP_ID);

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mContext = this;
    setContentView(R.layout.main);

    // Set up Facebook stuff
    mFacebook.authorize(this, new String[]{"user_checkins", "offline_access"}, new AuthorizeListener());

    // Set up map stuff
    MapView mMapView = (MapView)findViewById(R.id.map);
    mMapView.setSatellite(true);
    MapController mMapController = mMapView.getController();
    mMapController.animateTo(getCurrentLocation());
    mMapController.setZoom(3);

    // Set up overlay stuff
    mapOverlays = mMapView.getOverlays();
    Drawable drawable = this.getResources().getDrawable(R.drawable.icon);
    markerLayer = new FBCTMarkerOverlay(drawable);

    // markerLayer is populated in the AuthorizeListener sub-class
    mapOverlays.add(markerLayer);

}

/**
 * Determines the device's current location, but does not display it.
 * Used for centering the view on the device's location.
 * @return A GeoPoint object that contains the lat/long coordinates for the device's location.
 */
private GeoPoint getCurrentLocation() {
    LocationManager mLocationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
    Criteria mCriteria = new Criteria();
    mCriteria.setAccuracy(Criteria.ACCURACY_COARSE);
    mCriteria.setPowerRequirement(Criteria.POWER_LOW);
    String mLocationProvider = mLocationManager.getBestProvider(mCriteria, true);
    Location mLocation = mLocationManager.getLastKnownLocation(mLocationProvider);

    int mLat = (int)(mLocation.getLatitude()*1E6);
    int mLong = (int)(mLocation.getLongitude()*1E6);
    return new GeoPoint(mLat, mLong);
}

@Override
protected boolean isRouteDisplayed() {
    // TODO Auto-generated method stub
    return false;
}

private class AuthorizeListener implements DialogListener {
    public void onComplete(Bundle values) {
        new Thread() {
            @Override
            public void run() {
                try {
                    String response = mFacebook.request("me/checkins"); // The JSON to get
                                            JSONObject jObject = Util.parseJson(response);
                    JSONArray jArray = jObject.getJSONArray("data"); // Read the JSON array returned by the request
                    for (int i = 0; i < jArray.length(); i++) { // Iterate through the array
                        JSONObject outerPlace = jArray.getJSONObject(i); // The outer JSON object
                        JSONObject place = outerPlace.getJSONObject("place"); // Second-tier JSON object that contains id, name, and location values for the "place"
                        String placeName = place.getString("name"); // The place's name
                        JSONObject placeLocation = place.getJSONObject("location"); // Third-tier JSON object that contains latitude and longitude coordinates for the place's "location"
                        int lat = (int) (placeLocation.getDouble("latitude")*1E6); // The place's latitude
                        int lon = (int) (placeLocation.getDouble("longitude")*1E6); // The place's longitude
                        String date = outerPlace.getString("created_time"); // Timestamp of the checkin
                        overlays.add(new OverlayItem(new GeoPoint(lat, lon), placeName, "Checked in on: " + date)); // Add the place's details to our ArrayList of OverlayItems
                    }
                    mFacebook.logout(mContext); // Logout of Facebook
                    for (int i = 0; i < overlays.size(); i++) {
                        markerLayer.addOverlayItem(overlays.get(i));
                    }
                } catch(IOException e) {
                    Log.v("FBCTActivity", e.getMessage());
                } catch(JSONException e) {
                    Log.v("FBCTActivity", e.getMessage());
                }
            }
        }.start();
    }

    public void onFacebookError(FacebookError e) {
        Log.w("FBCTActivity", e.getMessage());
        // TODO: Add more graceful error handling
    }

    public void onError(DialogError e) {
        Log.w("FBCTActivity", e.getMessage());
    }

    public void onCancel() {
        // TODO Auto-generated method stub

    }
}

}

Answer 1

It might not be the reason but you haven't defined your app ID:

private static final String APP_ID = "";

Also, you have to override the onActivityResult in the activity where you call the mFacebook.authorize, so add this to your code:

    @Override
protected void onActivityResult(int requestCode, int resultCode,
                                Intent data) {
    mFacebook.authorizeCallback(requestCode, resultCode, data);
}

If you don't do so, your app won't get the token for the Graph and your connection will return a JSON error msg.