Question

i’m using facebook runner to apply some facebook api tesk.
i want to check if i got a JSON object with data or and error message so i’m checking the “message” field to check if it’s null.
if it is not null and i have a massage, i want to display the message and exit the application.

this is my code in my activity:

public class Loader extends Activity implements FacebookConnectionListener, ServerDataListener {
    private TextView loaderStatus;
    private Facebook facebook;
    private AsyncFacebookRunner facebookRunner;
    private FacebookConnection facebookConnection;   

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.loader);
        facebook = new Facebook(facebookAppId);
        facebookRunner = new AsyncFacebookRunner(facebook);
        facebookConnection = new FacebookConnection(this, 1);
        facebookRunner.request("me",facebookConnection);
    }

    @Override
    public void onFacebookResponse(final String response , int step) {
        final JSONObject facebookResults = convertToJSON(response);
        final Context thisContext = (Context) getBaseContext();
        String id = "", name = "", gender = "", homeTown = "";
        Drawable profilePicture = null;

        if (step == 1) {
            if (facebookResults.isNull("message")) {
                try {
                    id = facebookResults.getString("id");
                    name = facebookResults.getString("name");
                    gender = facebookResults.getString("gender");
                    JSONObject homeTownObject = (JSONObject) facebookResults.get("hometown");
                    homeTown = homeTownObject.getString("name");
                    profilePicture = getProfilePicture(id);

                } catch (JSONException e) { 
                    alert("Facebook", e.toString(), "Ok", thisContext);
                }
                facebookCurrentUser = new FacebookCurrentUser(id, name, gender);
                facebookCurrentUser.setHomeTown(homeTown);
                facebookCurrentUser.setProfilePicture(profilePicture);
                app.setFacebookCurrentUser(facebookCurrentUser);
                facebookConnection = new FacebookConnection(this, 2);   
                this.runOnUiThread(new Runnable() {
                public void run() {
                        loaderStatus.setText("Getting friends details");
                    }
                });
            }
            else {
                this.runOnUiThread(new Runnable() {
                    public void run() {
                        alert("Facebook", "Can't get user details! Please try again", "Ok", thisContext);
                    }
                }); 
            }           
        }

public void alert (String title, String message, String ok, Context listener)
{
    AlertDialog.Builder alert = new AlertDialog.Builder(listener);
    alert.setMessage(message);
    alert.setTitle(title);
    alert.setPositiveButton(ok, new OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            finish();   
        }
    });
    alert.show();
}

this is FacebookConnection class:

public class FacebookConnection implements RequestListener {
    private FacebookConnectionListener listener;
    private int step;

    public FacebookConnection (FacebookConnectionListener listener, int step) {
        this.listener = listener;
        this.step = step;
    }

    public void updateFacebookListener(String response) {
        listener.onFacebookResponse(response, step);
    }

    @Override
    public void onComplete(String response, Object state) {
        updateFacebookListener(response);           
    }

    @Override
    public void onIOException(IOException e, Object state) { }

    @Override
    public void onFileNotFoundException(FileNotFoundException e, Object state) { }

    @Override
    public void onMalformedURLException(MalformedURLException e, Object state) { }

    @Override
    public void onFacebookError(FacebookError e, Object state) { }
 }

the FacebookConnectionListener interface:

public interface FacebookConnectionListener {
    public void onFacebookResponse(String response, int step);
}

my alerts keep giving me the :

java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()

and i can’t understand why.. help ?

Answer 1

Well, try this:

public void alert (String title, String message, String ok) {
    this.runOnUiThread(new Runnable() {
        public void run() {
            AlertDialog alert = new AlertDialog.Builder(Loader.this).create();
            alert.setMessage(message);
            alert.setTitle(title);
            alert.setPositiveButton(ok, new OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    finish();
                }
            });
            alert.show();
        }
    });
}

Instead of what you have now, and when you call it, just call it like any other method:

this.alert("Facebook", "Can't get user details! Please try again", "Ok")

I’m not exactly sure where it goes wrong, it even might have to do with you forgetting the create() part when constructing the dialog.

Hope this will sort things for you.