Question

I have an Android application I’m working on, I’ve got the code working I’m just trying to clean it up a bit by moving certain functions into separate files. Whenever i try to call one of the functions from a separate file, however, it crashes saying FATAL EXCEPTION: AsyncTask #5. I have made a constructor in the separate file and I thought I was doing it correctly but I guess not. Any help is appreciated.

Here is my code:

DatabaseManager database;

public class loginTask extends AsyncTask<String, String, String> { 

    //check if server is online
    protected String doInBackground(String... params) {
        Log.d("test", "1");
        String username = params[0];
        String password = params[1];
        URI absolute = null;
        Log.d("test", "2");
        try {
            Log.d("test", "3");
            absolute = new URI("http://link.com/webservice/");
        } catch (URISyntaxException e) {
            Log.d("test", "4");
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Log.d("test", "5");
        database.test();//crashes at this line
        return postHttpResponse(absolute,username,password);
     }

     //set status bar to offline if flag is false
     protected void onPostExecute(String jsonstring) {
        try {
            //get values from jsonobject
            JSONObject jsonobj=new JSONObject(jsonstring);
            checkResponse(jsonobj);
            //errorMessage.setText(checkResponse(jsonobj));
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

     }
}

DatabaseManager.java

private final String LOGIN_TAG = "Login";
public DatabaseManager(){

}

public void test(){
Log.d(LOGIN_TAG, "this is a test");
}

Answer 1

You never instantiate DatabaseManager – so it stays null the entire time. Class scoped references stay null until they are given something to reference (either by pointing the new reference to an existing one or by making a new Object)

Consider doing

database = new DatabaseManager();
Log.d("test", "5");
database.test();//shouldn't crash at this line now